Petition for Writ of Certiorari — American Iron & Steel Institute v. United States Environmental Protection Agency

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IN THE

Supreme Court of the United States

OCTOBER TERM, 1990

AMERICAN IRON AND STEEL INSTITUTE,

Petitioner,

Vv.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY,

Respondent.

PETITION FOR A WRIT OF CERTIORARI TO THE

UNITED STATES COURT OF APPEALS

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Of Counsel: ROBERT A. EMMETT

BARTON C. GREEN (Attorney of Record)

AMERICAN IRON AND REED SMITH SHAW & McCLAY

STEEL INSTITUTE 1200 18th Street, N.W.

Washington, D.C. 20036

(202) 457-6144

Attorney for Petitioner

American Iron and

October 1, 1990 Steel Institute

WIL9ON - Eps PrinTING Co., INc. - 789-0096 - WASHINGTON, D.C. 20001

QUESTION PRESENTED

1. Whether the Environmental Protection Agency, in re-

vising the national ambient air quality standard for

particulate matter, violated Section 109(b) (i) of the

Clean Air Act when it failed to determine the par-

ticulate matter level that it deems to be safe to “pro-

tect the public health” and separately to determine

the additional protection necessary to provide an

“adequate margin of safety,” in each case articulat-

ing the scientific basis for its determination.

(i)

LIST OF PARTIES TO THE PROCEEDING BELOW

The case below was raised in six petitions for review

of federal agency action filed in and consolidated by the

United States Court of Appeals for the District of Co-

lumbia Circuit and docketed at Nos. 87-1438, 87-1441,

87-1442, 87-1448, 88-1913, and 89-1013. This Petition

for a Writ of Certiorari is based on claims presented in

petitions Nos. 87-1442, 87-1443, and 88-1913.

In Nos. 87-1442 and 87-1448, the American Iron and

Steel Institute (“AISI”)' was the petitioner, Alabama

Power Company, et al.,?> and the American Mining Con-

1 AISI is a trade association. AISI is not a corporation and does

not have a parent or subsidiary company to be listed pursuant to

Rule 29.1 of the Rules of the Supreme Court. Upon request, counsel

can compile and supply to the Court a list of AISI’s member

companies.

2“Alabama Power Company, et al.,” refers to Alabama Power

Company, Appalachian Power Company, Baltimore Gas and Electric

Company, Boston Edison Company, Carolina Power & Light Com-

pany, Centerior Energy Corporation, Cleveland Electric Illuminating

Company, Toledo Edison Company, Central and South West Serv-

ices, Inc., Central Power and Light Company, Public Service Com-

pany of Oklahoma, Southwestern Electric Power Company, West

Texas Utilities Company, Central Hudson Gas & Electric Corpora-

tion, Central Illinois Light Company, Central Illinois Public Service

Company, The Cincinnati Gas & Electric Company, Columbus South-

ern Power Company, Commonwealth Edison Company, Consolidated

Edison Company of New York, Inc., Consumers Power Company,

The Dayton Power and Light Company, Delmarva Power & Light

Company, The Detroit Edison Company, Duke Power Company,

Florida Power Corporation, Florida Power & Light Company,

Georgia Power Company, Gulf Power Company, Houston Lighting

& Power Company, Illinois Power Company, Indiana Michigan

Power Company, Indianapolis Power & Light Company, Iowa-

Illinois Gas and Electric Company, Iowa Public Service Company,

Kansas City Power & Light Company, Kentucky Power Company,

Kentucky Utilities Company, Madison Gas and Electric Company,

Mississippi Power Company, Monongahela Power Company, Montaup

Electric Company, New England Power Company, New York State

Electric & Electric Gas Corporation, Northern Indiana Public Serv-

lll

gress (“AMC”) were intervenor-petitioners, the United

States Environmental Protection Agency (“EPA”) and

the Administrator of the United States Environmental

Protection Agency (“Administrator”) were respondents,

and the Natural Resources Defense Council, Ince.

(“NRDC”) was intervenor-respondent.

In No. 88-1913, AISI was petitioner, Alabama Power

Company, et al., were intervenor-petitioners, EPA was

respondent, and NRDC was intervenor-respondent.

In No. 87-1438, NRDC, the State of Connecticut, the

Commonwealth of Massachusetts, the State of New Jer-

sey, the State of New York, and the State of Vermont

were petitioners, the Administrator and EPA were re-

spondents, and Alabama Power Company, et al., AISI,

AMC, and the National Coal Association (“NCA”) were

intervenor-respondents.

In No. 87-1441, AMC was petitioner, Alabama Power

Company, et al., and AISI were intervenor-petitioners,

the Administrator and EPA were respondents, and

NRDC was intervenor-respondent.

In No. 89-1013, AMC was petitioner, Alabama Power

Company, et al., and NCA were intervenor-petitioners,

EPA was respondent, and NRDC was _intervenor-

respondent.

ice Company, Ohio Edison Company, Pennsylvania Power Company,

Ohio Power Company, Ohio Valley Electric Corporation, Oklahoma

Gas and Electric Company, Pacific Gas and Electric Company,

Pennsylvania Electric Company, Pennsylvania Power & Light Com-

pany, The Potomac Edison Company, Potomac Electric Power Com-

pany, Public Service Company of Indiana, Inc., Public Service Elec-

tric and Gas Company, Salt River Project, Southern California

Edison Company, Tampa Electric Company, Tucson Electric Power

Company, Union Electric Company, Virginia Power Company, West

Penn Power Company, Wisconsin Electric Power Company, Wis-

consin Power and Light Company, Wisconsin Public Service Cor-

poration, the Edison Electric Institute, the National Rural Electric

Cooperative Association, and the American Public Power Association.

te id a Ty : y dt tae at ee.

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—

TABLE OF CONTENTS

QUESTION PRIEGIENTED quan .seneeseeceenesesenee

LIST OF PARTIES TO THE PROCEEDING BE-

LOW ...... ‘ .

ey Be i yi fy |

8, SC ee ae

JURISDICTION .................

STATUTE AND REGULATIONS INVOLVED ...........

STATEMENT OF THE CASE ooo... .eeeeeeeceneeeenneeeee

A. EPA’s National Ambient Air Quality Standards

for Particulate Matter ..........................................

B. The Proceedings Below ...................---0.cc-.ccccceeeeeeeeee

REASONS FOR GRANTING THE WRIT .....................

I. EPA MUST IDENTIFY A SAFE EXPOSURE

LEVEL FOR THE POLLUTANTS IT REGU-

LATES UNDER SECTION 109 .............

II. BY FAILING TO DEFINE SAFE EXPOSURE

LEVELS FOR ITS SECTION 109 STAND-

ARDS EPA HAS EXCEEDED ITS STATU-

TORY AUTHORITY AND PREVENTED

MEANINGFUL JUDICIAL REVIEYW ...............

CORY cents cnteiissnttuiinsinineabiainaiaiieitcheaiciniiansiiiciladhintaeen

APPENDIX

A. FINAL RULE OF THE UNITED STATES

ENVIRONMENTAL PROTECTION AGENCY:

Revisions to the National Ambient Air Quality

Standards for Particulate Matter, 52 Fed. Reg.

24634 (July 1, 1987) (excerpts) —......00000..0..

B. STATUTORY PROVISIONS .....02 eee

(v)

mn wp wo em GC.

TABLE OF AUTHORITIES

CASES: Page

A.L.A. Schechter Poultry Corp. v. United States,

BOE UB. GBE (IBGE) q.........-...n0nseecees--cccccerenccssereseee 16

American Petroleum Institute v. Costle, 665 F.2d

1176 (D.C. Cir. 1981), cert. denied, 455 US.

1084 (1982) (Ozone) .................-...........sceeseeeseee 11, 18, 15

Burlington Truck Lines v. United States, 371 U. S.

| 7) | 16

Industrial Union Dep’t., AFL-CIO v. American

Petroleum Inst., 448 U.S. 607 (1980) ................... 16

Lead Industries Association v. EPA, 647 F.2d

1180 (D.C. Cir.), cert. denied, 449 U.S. 1042

(RBBB) CLC) 2a -aaenceaccecesceccssecccemnsecesessessnssesnsnence 11, 18, 15

Natural Resources Defense Council, Inc. v. Admin-

istrator, U.S. Environmental Protection Agency,

824 F.2d at 1146 (D.C. Cir. 1987) (en banc)

(Vinyl Chloride) ..................-.----s-eeee- 8, 9, 11, 12, 18, 14

Natural Resources Defense Council, Inc., et al. v.

Administrator, U.S. Environmental Protection

Agency, et al., 902 F.2d 962 (D.C. Cir. 1990)... 1,9,

18, 15

Panama Refining Co. v. Ryan, 293 U.S. 388

CII aencenenceceresenerssnssarsnersnenerecesasssennnneneetsenscnmnnenen 16

STATUTES:

28 U.S.C. § 1254 (1) (1988) ............--.-..----eeceeceeeeeeees 2

28 U.S.C. § 2101 (c) (1988) ...........--.-------c-eceeeeeeeeeeeees 2

Clean Air Act, 42 U.S.C. § 7401, et seq. (1982) :

Section 108, 42 U.S.C. § 7408 (1982) ................. 2,10

Section 108(a) (1), 42 U.S.C. § 7408(a) (1)

CRED anenenecseveessernescsennseeesesensaneessnnscensnenesetenetans 4

Section 109, 42 U.S.C. § 7409 (1982) ................. passim

Section 109 (a), 42 U.S.C. § 7409(a) (1982)... 4

Section 109(b) (1), 42 U.S.C. § 7409(b) (1)

CRIED nan cacenencennnnneneeetenscnncemnsewnnqeencennnnnneenennonse 4,10

Section 110(a) (2) (I), 42 U.S.C. § 7410(a)

CB) CH) CRG) naan nana nnnnsncenn-arecenvsccnceresenesseseseee 3

Section 112, 42 U.S.C. § 7412 (1982) ......... 2, 8, 9, 11,

12, 18, 14

Section 113(a), 42 U.S.C. § 7415 (a) (1982).. 3

vii

TABLE OF AUTHORITIES—Continued

LEGISLATIVE MATERIALS:

2 Sen. Comm. on Public Works, 98d Cong., 2d

Sess., Air Quality and Automobile Emission

Control 401 (Comm. print ES

FEDERAL REGISTER:

MISCELLANEOUS:

Jorling, The Federal Law of Air Pollution Control,

FEDERAL ENVIRONMENTAL Law, 1066 (1974)...

National Air Quality Criteria Advisory Commit-

tee, Science Advisory Board, Report on Air

Quality Criteria for Particulate Matter (1976) ..

Regulatory Impact Analysis of the National Am-

bient Air Quality Standards for Particulate

Matter, Second Addendum (Dec. 1986) ..............

IN THE

Supreme Court of the United States

OCTOBER TERM, 1990

No.

AMERICAN IRON AND STEEL INSTITUTE,

7 Petitioner,

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY,

Respondent.

PETITION FOR A WRIT OF CERTIORARI TO THE

UNITED STATES COURT OF APPEALS

FOR THE DISTRICT OF COLUMBIA CIRCUIT

The American Iron and Steel Institute (“AISI”) re-

spectfully petitions for a writ of certiorari to review the

judgment of the United States Court of Appeals for the

District of Columbia Circuit entered or April 27, 1990,

in the case of Natural Resources Defense Council, Inc.,

et al. v. Administrator, U.S. Environmental Protection

Agency, et al., No. 87-1438 and consolidated cases.

OPINION BELOW

The April 27, 1990 opinion of the United States Court

of Appeals for the District of Columbia Circuit in Nat-

ural Resources Defense Council, Inc., et al. v. Adminis-

trator, U.S. Environmental Protection Agency, et al., No.

87-1438 and consolidated cases, is reported at 902 F.2d

962 and is reprinted in the Appendix to the Petition for

a Writ of Certiorari (No. 90-257) filed by the National

Coal Association (“NCA App.”) at la.’

1 The Petition in No. 90-257, National Coal Association v. Natural

Resources Defense Council, Inc., et al., is from the same judgment

The opinion below addresses final rulemaking pub-

lished by the United States Environmental Protection

Agency (“EPA”) entitled Revisions to the National

Ambient Air Quality Standards for Particulate Matter,

published at 52 Fed. Reg. 24634 (July 1, 1987), perti-

nent portions of which are reprinted in the Appendix

(“App.”) to this Petition at la-53a.

JURISDICTION

The judgment of the United States Court of Appeals

for the District of Columbia Circuit was entered on

April 27, 1990. See NCA App. at la. A timely filed pe-

tition for rehearing was denied by that court on July 3,

1990. NCA App. at 93a. This Petition is filed within 90

days of the July 3, 1990 denial of the petition for re-

hearing in accordance with 28 U.S.C. 2101(¢c) (1988)

and Rules 13.1 and 13.4 of the Rules of this Court. This

Court’s jurisdiction is invoked pursuant to 28 U.S.C.

§ 1254(1) (1988).

STATUTE AND REGULATIONS INVOLVED

This case involves Section 109 of the Clean Air Act,

as amended, 42 U.S.C. § 7409 (1982). The pertinent

provisions of Section 109 and related Sections 108 and

112, 42 U.S.C. §§ 7408 and 7412 (1982), together with

the regulations at issue herein are set forth in Appendix

A and B hereto, respectively, at 54a and la.

STATEMENT OF THE CASE

This case addresses the manner in which EPA prop-

erly can exercise its far-reaching authority to set na-

tional ambient air quality standards under Section 109

of the court below which is the subject of this Petition. This Peti-

tion presents different questions from those raised in No. 90-257.

We believe the Court should grant review in No. 90-257 but do not

plan to file a pleading in response to the National Coal Association

Petition.

of the Clean Air Act.? Once EPA establishes a Section

109 standard, that standard, within statutorily-prescribed

time periods, must be met in every corner of the country.

Cities and industrial areas that fail to meet Section 109

standards are subject to severe regulatory and economic

sanctions.* Individual piants and sources deemed to be

contributing to air pollutant levels that exceed a Section

109 standard must install emission controls which re-

quire major expenditures for nonproduction-related

equipment. Sources that violate their control require-

ments are subject to enforcement proceedings and civil

penalties or criminal fines of $25,000 per day.*

As one commenter noted in 1974:

The Clean Air Act, coupled with the new 1972 Water

Pollution Control Act Amendments, grants regula-

tory power to the administrator of EPA far beyond

that possessed by other traditional federal regulatory

commissions. These two environmental acts regulate

not just one or another industry type or practice, but

rather regulate nearly all industry, and, more im-

portantly, the behavior of all citizens, through trans-

portation and other controls.

Jorling, The Federal Law of Air Pollution Control, FEp-

ERAL ENVIRONMENTAL LAw, 1066 (1974). An unneces-

sarily stringent Section 109 standard can waste resources

242 U.S.C. § 7409 (1982). Hereinafter, citations to the Clean

Air Act are to sections of the Act. The Table of Authorities pro-

vides parallel citations to the United States Code.

3% See, generally, Part D of Title I of the Clean Air Act and, in

particular, Sections 172 (requiring the states to adopt stringent new

planning and regulatory mechanisms for areas not meeting an

NAAQS) and 176 (cutting off certain federal grants for areas not

meeting an NAAQS and failing to take remdial measures required

by Part D). See also, Section 110(a) (2) (1) (banning the construc-

tion or modification of major emission sources in areas not meeting

an NAAQS and lacking an approved Part D plan).

4 See Section 113(b), (c).

and impair American industry and its ability to compete

internationally.

Section 109 requires EPA to establish national am-

bient air quality standards to “protect the public health”

and further to specify an ‘adequate margin of safety.”

The D.C. Circuit ruled in the case below and on two

other occasions that EPA may set Section 109 standards

without identifying either the level at which a particular

pollutant is safe for the public health or the magnitude

of the safety margin it applied to its safe exposure de-

termination. The D.C. Circuit further stated in the de-

cision below that “uncertainty” in the data relied upon

by EPA made unnecessary any such “further articula-

tion” of EPA’s basis for its Section 109 standards.

A. EPA’s National Ambient Air Quality Standards for Par-

ticulate Matter

The Clean Air Act, as enacted in 1970, established,

among other things, a framework for the regulation of

common, ubiquitous air pollutants. EPA first was re-

quired to identify air pollutants emitted from “numerous

or diverse mobile or stationary sources” which in the

ambient air ‘‘may reasonably be anticipated to endanger

public health or welfare.” Section 108(a) (1). For each

pollutant so identified, EPA must issue national ambient

air quality standards (“standards” or “NAAQS’). Sec-

tion 109(a). So-called “primary” or health-related

NAAQS must be set at levels which “allowing an ade-

quate margin of safety, are requisite to protect the pub-

lic health.” Section 109(b) (1).

“Particulate matter” is a generic term for airborne

particles (liquid droplets or solids) of chemically and

physically diverse substances. Such particles originate

from many natural and man-made sources, both mobile

and stationary, ranging from dust storms, sea spray, and

voleanic activity to dirt roads and various industrial and

agricultural activities.

The first particulate matter NAAQS were adopted by

EPA in 1971 and were expressed in terms of Total Sus-

pended Particulate (“TSP”). TSP is a measure of par-

ticulate matter captured by an air sampling device known

as a high volume sampler, which collects particles up to

sizes of 25 to 45 micrometers.

In setting a 24-hour TSP primary standard in 1971,

EPA relied on effects levels reported by British scientists

in studies carried out in Greater London over two decades

starting in the 1950s. EPA erred, however, by treating

the British Smoke measurement units reported in the

British studies as equivalent to the more particle-inclusive

TSP measure used for the U.S. standards. This error,

although never publicly acknowledged by EPA, was noted

by the National Academy of Sciences in 1974° and by

EPA’s own appointed science advisors.*° By treating the

TSP measure as equivalent to the British Smoke measure,

EPA incorrectly ascribed adverse health effects to TSP

levels half as high as the levels reported in the British

studies upon which EPA relied.’ Because of this and other

errors, EPA’s science advisors concluded in 1976 that re-

vision of the scientific documents upon which the original

particulate matter standards were based was “not only

desirable, but necessary.” *

Eight — later, in 1984, EPA proposed revisions to

the particulate matter standards.® In the preamble

5 See 2 Sen. Comm. on Public Works, 93d Cong., 2d Sess., Air

Quality and Automobile Emission Control 401 (Comm. Print 1974).

6 See National Air Quality Criteria Advisory Committee, Science

Advisory Board, Report on Air Quality Criteria for Particulate

Matter (1976).

7 Id. at 27.

8 Jd. at 1.

® See Proposed Revisions to the National Ambient Air Quality

Standards for Particulate Matter, 49 Fed. Reg. 10408 (Mar. 20,

1984).

thereto, then EPA Administrator Ruckelshaus stated that

“the selection of a single air quality standard . . . pre-

sents an extraordinarily difficult regulatory problem, one

for which the existing legislative decision criteria may

well be inadequate.” 49 Fed. Reg. at 10409. He further

noted that the scientific data base for applying an ade-

quate margin of safety was “even more sparse and un-

certain,’ and that “[n]o ‘scientific’ approach for select-

ing any single recommended standard seems possible

against this background.” /d.

The Administrator noted that the courts “appear” to

have ruled out consideration of economic and technological

factors in setting ambient standards, leaving “some doubt

whether the Administrator may even consider the prac-

tical problems of implementation to guide his choice.” Jd.

EPA’s public health review as of that date “revealed no

scientific method of assessing exactly what level of stand-

ards public health requires. The scientific review indi-

cates substantial uncertainties concerning the health risks

associated with lower levels of particulate matter.” Jd.

Because of this “substantial degree of uncertainty,”

EPA proffered “ranges of interest’? from which the final

standards likely would be chosen. Jd. at 10415. EPA

proposed to select (1) a 24-hour primary standard from

a range of 150 to 250 micrograms per cubic meter (yg/

m*), and (2) an annual primary standard from a range

of 50 to 65 micrograms per cubic meter (ng/m*). Id. at

10408. EPA also proposed to replace TSP as the indi-

eator for particulate matter with a new, size-specific in-

dicator designed to measure only particles with an aero-

dynamic diameter equal to or smaller than 10 microm-

eters. Jd. EPA had determined that TSP particles larger

than 10 micrometers had no significant impact on health

and, therefore, should not be regulated. Jd. at 10412.

EPA referred to the new indicator as PM,,. Jd.

In its June 3, 1985 comments '® on the proposed PM,,

standards, AISI objected to EPA’s attempt to inject scien-

tific uncertainty as justification for maintaining the er-

roneously stringent TSP standards as a basis for the new

PM,, standards. By 1984, the scientific community, if not

EPA, generally had acknowledged that the present stand-

ards were scientifically invalid because of the faulty ap-

plication of British Smoke measurements.'! AISI also

quoted from remarks presented by Dr. A. Fraas of the

Office of Management and Budget noting that since EPA

was “unable to identify any clear evidence of adverse

health effects at or near current ambient levels, it has

made the uncertainty in the available evidence into a vir-

tue by arguing that the current statute requires a con-

servative approach to protecting public health.” !”

AISI further stated in its comments that EPA cannot

use the lack of scientific evidence absolutely ruling out

adverse health effects at low levels of PM,, exposure to

set the primary NAAQS essentially at any level it pleases.

Such use by EPA of Section 109, if permitted, would in-

dicate an excessive delegation to EPA of legislative power

which would raise Constitutional questions."

EPA promulgated the final standards on July 1, 1987."

EPA retained the PM,, indicator but selected the final

standards from the bottom of its proposed ranges. The

final 24-hour standard was set at 150 micrograms per

cubic meter (»g/m*), and the annual standard was set

at 50 micrograms per cubic meter (»g/m*). EPA’s reg-

ulatory impact analysis predicted that attaining the new

10 AISI’s June 3, 1985 comments (“AISI Comments’) were dock-

eted in the PM,, rulemaking proceeding at No. A-82-37, IV-D-254.

11 See p. 5 supra.

12 AISI Comments at 88.

13 AISI Comments at 98-101.

14 See Revisions to the National Ambient Air Quality Standards

for Particulate Matter, 52 Fed. Reg. 24634 (July 1, 1987), App. la.

standards at these levels would cost nearly $2 billion (dis-

counted present value in 1983),’° one tenth of which, or

approximately $200 million, will be borne by the steel

industry."®

On October 28, 1987, AISI submitted a Petition to EPA

for Reconsideration of the final standards on the basis of

(a) new health effects data which AISI submitted with

its Petition, and (b) the D.C. Circuit’s decision in Nat-

ural Resources Defense Council, Inc. v. Administrator,

U.S. Environmental Protection Agency, 824 F.2d 1146

(D.C. Cir. 1987) (en banc) (Vinyl Chloride) (holding

that EPA, in establishing emission standards for hazard-

ous air pollutants under Section 112 of the Act, must

separately determine a “safe” level of exposure prior to

applying an ample margin of safety). More than a year

later, EPA denied AISI’s Petition for Reconsideration."

B. The Proceedings Below

Pursuant to and under the authority of Section 307 (b)

(1) of the Act, AISI appealed EPA’s final standards and

EPA’s denial of AISI’s Petition for Reconsideration in

petitions for review filed in the D.C. Circuit and consoli-

dated with others in the case below. AISI challenged the

final standards on a number of scientific and legal grounds

as arbitrary and capricious and contrary to law. AISI

also pointed out that EPA failed to identify a safe level

for PM,, contrary to the requirements of Section 109 of

the Clean Air Act and contrary to the D.C. Circuit’s

Vinyl Chloride decision. :

The panel below excused EPA’s failure to denote a

“safe” level of exposure for PM,, by reasoning that the

15 Regulatory Impact Analysis of the National Ambient Air Qual-

ity Standards for Particulate Matter, Second Addendum (Dec. 1986)

at II-20.

16 Jd, at II-25.

17 See 53 Fed. Reg. 52698 (Dec. 29, 1988).

Vinyl Chloride decision construing Section 112 of the

Clean Air Act did not apply to determinations under Sec-

tion 109.** The court below found that the uncertainty of

the data upon which the Administrator based the final

standards made it unnecessary for EPA to articulate the

“risk it considered tolerable in meeting the requirements

of providing a reasoned explanation for an administra-

tive decision.”

Alabama Power Company, et al.,* intervenors in the

D.C. Circuit proceedings below, filed a timely petition for

rehearing and suggestion for rehearing en banc on an

unrelated issue involving acid deposition. The court below

denied the petition and suggestion on July 3, 1990.

REASONS FOR GRANTING THE WRIT

This Court has decided twelve cases arising under the

Clean Air Act since that act was first enacted twenty

years ago in 1970. To date, however, this Court has not

heard a case involving Section 109, the most pervasive

and far-reaching provision in the statute. Section 109

gives the Administrator the power to dictate the contents

of the air we breathe and in so doing can redirect mas-

sive capital investment from growth and increased pro-

duction to air emission control systems. To the extent

Section 109 standards are unnecessarily stringent, plants

may be shut down and jobs lost, with concomitant social

and economic dislocation and a variety of adverse direct

and indirect effects, including deterrence of new invest-

ment and impaired international competitiveness.

Although the impact of the PM,, standards is nation-

wide, only one court, the U.S. Court of Appeals for the

District of Columbia Circuit, may review their propriety.

18 Natural Resources Defense Council, Inc. v. Administrator, U.S.

Environmental Protection Agency, 902 F.2d 962, at 973-74, NCA

App. at 22a-23a.

19 Jd. at 974, NCA App. at 23a.

20 See p. ii n.2, supra, for a list of these companies.

See Section 307(b) (1). Any challenge to the PM,, stand-

ards must be brought within 60 days of promulgation.

Id. Thereafter, the PM,, standards are not subject to

challenge, not even as a defense in civil or criminal en-

forcement proceedings. Section 307(b)(2). The Clean

Air Act’s judicial review preclusion provisions thus elimi-

nate any possibility of a conflict among the circuits or

any further challenges to the PM,, standards. Unique

issues raised by the PM,, standards will not develop,

ripen, or otherwise become more focused in other forums

over time. Now that the D.C. Circuit has acted, only the

Supreme Court may address the issues raised by the

PM,, standard and only on this singular occasion.

I. EPA MUST IDENTIFY A SAFE EXPOSURE

LEVEL FOR THE POLLUTANTS IT REGULATES

UNDER SECTION 109

Congress did not and cannot make in Section 109 an

unfettered delegation to EPA of authority to set stand-

ards of critical and national importance. Section 109

(b) (1) requires that NAAQS

shall be ambient air quality standards the attainment

and maintenance of which in the judgment of the

Administrator, based on such criteria and allowing

an adequate margin of safety, are requisite to pro-

tect the public health.

On its face, Section 109(b) (1) thus imposes three, sepa-

rate limits upon EPA’s standard setting discretion.

First, Section 109(b) (1), requires that primary NAAQS

“shall be based on . . . criteria” identified pursuant to

Section 108. Second, primary NAAQS must be “requisite

to protect the public health.” Third, primary NAAQS

must allow an “adequate margin of safety.”

With regard to the first limit or requirement, that

NAAQS be based upon criteria identified by EPA pur-

suant to Section 108, AISI raised numerous objections

below to EPA’s mischaracterization and misuse of the

available scientific data in the particulate matter criteria

MMi

document and in setting the final primary PM,, stand-

ards. For example, as already noted,?* EPA misapplied

the British data upon which it relied in setting its origi-

nal 1971 TSP standards, making the TSP standards at

least twice if not three times too stringent, and never

acknowledged or corrected that error but rather per-

petuated it when EPA set the new PM,, standards.

For purposes of this Petition, however, AISI focuses

on the second and third requirements of Section 109.

EPA has failed to identify either the level of PM,, “req-

uisite te protect the public health” or the magnitude of

the “adequate margin of safety” which it applied to that

level. EPA declined to make similar determinations when

it established an NAAQS for lead in 1978. The D.C. Cir-

cuit upheld this omission in Lead Industries Association

v. EPA, 647 F.2d 1130 (D.C. Cir.), cert. denied, 449

U.S. 1042 (1980) (Lead). EPA again failed to make

these determinations in establishing a revised NAAQS

for ozone in 1979. The D.C. Circuit excused this omis-

sion in American Petroleum Institute v. Costle, 665 F.2d

1176 (D.C. Cir. 1981), cert. denied, 455 U.S. 1034 (1982)

(Ozone).

In 1976 and 1985, in separate proceedings respectively

establishing and retaining with minor revisions an emis-

sion standard for the hazardous air pollutant vinyl

chloride under Section 112 of the Clean Air Act, EPA

again did not identify a health effects threshold for vinyl

chloride, a strong carcinogen. Section 112 requires EPA

to establish standards governing emissions of hazardous

air pollutants at levels that “protect the public health”

with an “ample margin of safety.” Section 109 has simi-

lar requirements but requires a lesser, “adequate” mar-

gin of safety.

In the Vinyl Chloride case, supra, which reviewed

EPA’s withdrawal of proposed amendments to the Section

112 vinyl chloride standard, Petitioner Natural Resources

21 See p. 5 supra.

Defense Council, Inc. argued that the mandate to protect

the public health with an “ample” margin of safety re-

quired that all emissions of vinyl chloride be banned. See

824 F.2d at 1152. This contention was unanimously re-

jected by the D.C. Circuit sitting en banc. Id. at 1154.

Instead, the D.C. Circuit reversed and remanded the

vinyl chloride standard because EPA had failed to make

basic determinations required by the Act. The D.C. Cir-

cuit stated that, in setting national emission standards

for hazardous air pollutants under Section 112, “the con-

gressional mandate to provide ‘an ample margin of

safety’ ‘to protect the public health’ requires EPA to

make an initial determination of what is ‘safe’.” Jd. at

1164. EPA may not consider cost or technical feasibility

in determining what is “safe”; such a determination

must be “based solely upon the risk to health.” Jd. at

1166. Noting that “safe” does not mean “risk-free,” the

D.C. Circuit ruled that EPA “must” decide “what risks

are acceptable in the world in which we live.” Jd. at

1165. Once EPA has determined a “safe” level of ex-

posure, the D.C. Circuit found that EPA could weigh

considerations in addition to health such as cost or feasi-

bility in applying the “ample margin of safety’’ required

by Section 112. 7d.

The Vinyl Chloride decision was handed down shortly

after EPA issued the final PM,, standards. AISI sub-

mitted a Petition to EPA for Reconsideration of the final

PM,, standards, in part to give EPA an opportunity to

apply the Vinyl Chioride analysis and to evaluate the

degree of “safety” that would be provided by the various

levels within the ranges proposed for the primary PM,,

standards. Both EPA, in denying AISI’s Petition for

Reconsideration, and the court below refused to apply the

Vinyl Chloride rationale to EPA’s standard setting under

Section 109.

The court below found that “the two-step methodologi-

cal requirement endorsed by Vinyl Chloride was neces-

sary because of the need under § 112 to sever determina-

tions that must be based solely on health considerations

from those that may include economic and technological

considerations.” 902 F.2d at 973, NCA App. at 22a.

Noting its previous Lead and Ozone decisions (id., NCA

App. at 2la), the court below stated that EPA may not

consider cost or technoicgical feasibility at any stage of

standard setting under Section 109. Jd., NCA App. at

22a. Because of this, the court below found that the

rationale for separate identification of a safe level and

the margin of safety applied thereto was “inapposite” to

actions under Section 109. Jd. This “foreclosure from

consideration of cost and technological feasibility” per-

suaded the court below that Section 109 “itself does not

mandate the methodological requirement we found neces-

sary under § 112.” Id., NCA App. at 23a.

The concern of the court below over economic and

technological feasibility is misplaced. The mandate in

Sections 109 and 112 “to protect the public health” neces-

sitates a “safe” exposure level determination whether or

not EPA considers such other factors as economic or tech-

nological feasibility. See, Vinyl Chloride, 824 F.2d at

1164-65 & n.11.

The distinction between Section 112 for vinyl chloride

and Section 109 for PM,. proffered by the court below

makes no rational sense. Vinyl chloride is a “strong

carcinogen” with a long and uncertain latency period.”

The evidence in that case suggested that there was no

apparent safe exposure level for vinyl chloride.” Despite

the extreme dangers and substantial uncertainties posed

by the chemical in question, the D.C. Circuit in Vinyl

Chloride found that EPA’s standard setting responsibili-

ties included the identification and determination of cer-

tain parameters such as a safe exposure level and the

22 Vinyl Chloride, 824 F.2d at 1148.

23 Id.

magnitude of the margin of safety applied to that level.

With respect to PM,., however, a relatively benign pol-

lutant at lower concentration levels with only minimal

transitory effects on even the most sensitive populations,

the court below declined te impose the minimal procedural

requirements the Vinyl Chloride decision found inherent

in Section 112.

When dealing with more dangerous, life-threatening

Section 112 hazardous chemicals or carcinogens for which

an “ample” margin of safety is to be applied, EPA is

required to determine the safe exposure level and not just

a final standard with an unquantified, purportedly “am-

ple’ margin of safety. EPA should not be given more

discretion and held to a lower standard of care and ar-

ticulation when it addresses commonplace pollutants ad-

dressed by Section 109, to which a less than ample, “ade-

quate” safey margin is to be applied.* The Clean Air

Act requires EPA to make certain fundamental determi-

nations in setting standards for dangerous pollutants.

Certainly such procedures should be applied to the estab-

lishment of nationally applicable standards for the

ubiquitous but considerably less dangerous pollutants

regulated under Section 109, particularly since overly

stringent standards can result in plant shutdowns, wide-

spread unemployment and adverse health impacts found

to result from unemployment.

24 Section 109 pollutants are widespread and commonly encoun-

tered (resulting from “numerous or diverse mobile or stationary

sources”) and “may reasonably be anticipated to endanger public

health or welfare.” Section 112 hazardous air pollutants, however,

are less common but when encountered “may reasonably be antici-

pated to result an increase in mortality or an increase in serious

irreversible, or incapacitating reversible, illness.”

Il. BY FAILING TO DEFINE SAFE EXPOSURE LEV-

ELS FOR ITS SECTION 109 STANDARDS EPA HAS

EXCEEDED ITS STATUTORY AUTHORITY AND

PREVENTED MEANINGFUL JUDICIAL REVIEW

If, as concluded by the D.C. Circuit on three separate

occasions in the Lead and Ozone decisions and the pres-

ent PM,, decision, EPA has discretion to establish an

ambient standard without ever having to determine what

air quality level is “safe,” or what is an adequate margin

of safety, EPA can, as it proved with the PM,, stand-

ards, choose virtually any level, and its selection is es-

sentially unreviewable. EPA need only state for the

record that it reviewed the available scientific evidence,

state that its review disclosed no obvious answers, and

then select a number, any number for the final standard.

The court below gives EPA this latitude because it won’t

require EPA to identify the “safe” exposure level as a

benchmark against which to compare the standard.

Instead, the decision below announces the proposition

that the greater the scientific uncertainty, the greater

the latitude to be accorded the agency and the less artic-

ulation is required. 902 F.2d at 974, NCA App. at 28a.

In other words, the less support EPA can adduce for a

Section 109 standard, the greater the deference EPA is

to be accorded. Such deference seriously reduces, if not

eliminates, any meaningful role for the reviewing court.

Absent any indication in the record of what risks EPA

deems to be acceptable, the reviewing court has no basis

against which to evaluate EPA’s judgment.

The decision below actually excuses, and conceivably

encourages, scientific imprecision and lack of data for

governmental standard setting. If scientific uncertainty

increases agency discretion, and, in turn, judicial defer-

ence, agencies have no impetus to generate or commission

the scientific data necessary for setting standards.

Under a proper reading of Section 109, not only is

EPA required to identify both the health protective limit

and the margin of safety applied thereto, EPA also is

required to articulate clearly and separately the appro-

priate factors relevant to each such determination. Such

a delineation is necessary to assure that each determina-

tion is made in a rational manner with due consideration

of the different factors applicable to each and to assure

that the courts are able to discharge their review func-

tion properly. As this Court aptly pointed out:

Expert discretion is the lifeblood of the administra-

tive process, but “unless we make the requirements

for administrative action strict and demanding, ex-

pertise, the strength of modern government, can be-

come a monster which rules with no practical limits

on its discretion” (citation omitted).

Burlington Truck Lines v. United States, 371 U.S. 156,

167 (1962).

To permit EPA to speculate as to theoretical health

risks, without regard to the certain harm to the public

welfare that flows from unduly stringent standards and

without guidance as to where on the continuum of rela-

tive safety the Administrator should draw his line, as the

decision of the court below permits, would be a “sweep-

ing delegation of legislative power” that raises serious

Constitutional questions. See, A.L.A. Schechter Poultry

Corp. v. United States, 295 U.S. 495, 5389 (1935);

Panama Refining Co. v. Ryan, 293 U.S. 388 (1935).

See also Industrial Union Dep’t. AFL-CIO v. American

Petroleum Inst., 448 U.S. 607 (1980) (Plurality Opin-

ion), 671 (Rehnquist, J., concurring in the judgment).

The Court need not address this issue here, however, be-

cause the court below erred in its construction of the

basic requirements of Section 109.

This Court should clarify the requirements of Section

109 by granting this Petition and by concluding that, in

setting standards under Section 109, EPA must separ-

ately determine the safety level for the pollutant in ques-

eee DO ee Bihne eine ee

tion and the margin of safety it applied to that level and

for each determination articulate its rationale.

CONCLUSION

For the forgoing reasons, this Petition for a Writ of

Certiorari should be granted.

Respectfully submitted,

Of Counsel: ROBERT A. EMMETT

BARTON C, GREEN (Attorney of Record)

AMERICAN IRON AND REED SMITH SHAW & MCCLAY

STEEL INSTITUTE 1200 18th Street, N.W.

Washington, D.C. 20036

(202) 457-6144

Attorney for Petitioner

American Iron and

October 1, 1990 Steel Institute

APPENDICES

APPENDIX A

FINAL RULE OF THE UNITED STATES

ENVIRONMENTAL PROTECTION AGENCY

(Excerpts)

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 50

[AD-FRL 3141-9 (a) ]

Revisions to the National Ambient Air Quality

Standards for Particulate Matter

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

SUMMARY: In 1971, EPA promulgated primary and

secondary national ambient air quality standards for

particulate matter, measured as “total suspended partic-

ulate matter” or “TSP.” The primary standards were

set at 260 »g/m*, 24-hour average not to be exceeded

more than once per year, and 75 »g/m*, annual geometric

mean. The secondary standard, also measured as TSP,

was set at 150 ug/m*, 24-hour average not to be exceeded

more than once per year. In accordance with sections

108 and 109 of the Clean Air Act, EPA has reviewed and

revised the health and welfare criteria upon which these

primary and secondary particulate matter standards

were based.

On March 20, 1984 (49 FR 10408), EPA proposed

changes in the standards based on its review and revision

of the criteria. Today’s notice announces EPA’s final

decisions regarding these changes. The final decisions in-

clude: (1) replacing TSP as the indicator for particu-

late matter for the ambient standards with a new indi-

cator that includes only those particles with an aerody-

namic diameter less than or equal to a nominal 10 micro-

meters (PM,,), (2) replacing the 24-hour primary TSP

standard with a 24-hour PM,, standard of 150 ,»g/m*

with no more than one expected expected exceedance per

year; (3) replacing the annual primary TSP standard

with a PM,, standard of 50 y»g/m*, expected annual

arithmetic mean; and (4) replacing the secondary TSP

standard with 24-hour and annual PM,, standards that

are identical in all respects to the primary standards.

* * * *

Table of Contents

I. Background

A. Legislative Requirements Affecting This Rule

1. The Standards

2. Related Control Requirements

Particulate Matter and Original Standards for TSP

C. Development of Revised Air Quality Criteria for

Particulate Matter

D. Review of the Standards: Development of Staff

Paper

E. Proposed Revisions to the Standards

F. Supplemental Criteria Revisions and Standards Re-

view Following Proposal

II. Summary of Public Comments

A. Comments on 1984 Proposal

B. Comments on Subsequent Notice

III. Rationale for the Primary Standards

A. Pollutant Indicator

B. Averaging Time and Form of the Standards

1, 24-hour Standard

2. Annual Standard

VI.

VIL.

VIII.

C. Level of the Standards

1. 24-hour standard

2. Annual Standard

Rationale for the Secondary Standards

A. Soiling and Nuisance

B. Other Welfare Effects

Federal Reference Method

A. Specific Changes to Appendix J

B. Designation of Reference Methods for PM,,

C. Technical Change to Appendix G

Summary of Salient Public Comments and Agency

Responses

A. Health Effects Criteria and Selection of the Pri-

mary Standards

1. Indicater for the Primary Standards

2. Interpretation of Community Epidemiological

Studies

3. Margin of Safety

B. Secondary Standards

1. Soiling and Nuisance

2. Visibility

C. Averaging Time and Form of the Standards

1. Expected Exceedances for the 24-hour Standard

2. Expected Arithmetic Mean for the Annual

Standard

Regulatory and Environmental Impacts

A. Regulatory Impact Analysis

B. Impact on Small Entities

Other Reviews

References

Addendum I—CASAC Review and Closure of the 1982 Cri-

teria Document for Particulate Matter/Sulfur Oxides and

the 1986 Second Addendum to the Criteria Document

Addendum II—CASAC Review and Closure of the 1982

OAQPS Staff Paper for Particulate Matter and the 1986

Addendum to the Staff Paper

Addendum III—Executive Summary of the 1986 Addendum

to the Staff Paper

Part 50—National Primary and Secondary Ambient Air

Quality Standards

Appendix J—Reference Method for the Determination of

Particulate Matter as PM,, in the Atmosphere

Appendix K—Interpretation of the National Ambient Air

Quality Standards for Particulate Matter

I. Background

A. Legislative Requirements Affecting This Rule

1. The Standards

Two sections of the Clean Air Act govern the establish-

ment and revision of national ambient air quality stand-

ards (NAAQS). Section 108 (42 U.S.C. 7408) directs

the Administrator to identify pollutants which may rea-

sonably be anticipated to endanger public health or wel-

fare and to issue air quality criteria for them. These air

quality criteria are to reflect the latest scientific infor-

mation useful in indicating the kind and extent of all

identifiable effects on public health or welfare that may

be expected from the presence of a pollutant in the am-

bient air.

Section 109 (42 U.S.C. 7409) directs the Administra-

tor to propose and promulgate “primary” and “sec-

ondary” NAAQS for pollutants identified under section

108. Section 109(b)(1) defines a primary standard as

one the attainment and maintenance of which, in the

judgment of the Administrator, based on the criteria and

allowing for an adequate margin of safety, is requisite

to protect the public health. A secondary standard, as

defined in section 109(b) (2), must specify a level of air

quality the attainment and maintenance of which, in the

judgment of the Administrator, based on the criteria,

is requisite to protect the public welfare from any known

or anticipated adverse effects associated with the presence

of the pollutant in the ambient air. Welfare effects

are defined in section 302(h) (42 U.S.C. 7602(h)) to

include effects on soils, water, crops, vegetation, man-

made materials, animals, wildlife, weather, visibility,

climate, damage to and deterioration of property, hazards

to transportation, and effects on economic values and on

personal comfort and well-being.

The U.S. Court of Appeals for the D.C. Circuit has

held that the requirement for an adequate margin of

safety for primary standards was intended to address

uncertainties associated with inconclusive scientific and

technical information available at the time of standard

setting. It was also intended to provide a reasenable

degree of protection against hazards that research has

not yet identified. Lead Industries Association v. EPA,

647 F.2d 1130, 1154 (D.C. Cir. 1980), cert. denied, 101

S. Ct. 621 (1980); American Petroleum Institute v.

Costle, 665 F.2d 1176, 1177 (D.C. Cir. 1981), cert.

denied, 102 S. Ct. 1737 (1982). Both kinds of uncertain-

ties are components of the risk associated with pollution

at levels below those at which human health effects can

be said to occur with reasonable scientific certainty.

Thus, by selecting primary standards that provide an

adequate margin of safety, the Administrator is seeking

not only to prevent pollution levels that have been demon-

strated to be harmful, but also to prevent lower pollutant

levels that he finds pose an unacceptable risk of harm,

even if that risk is not precisely identified as to nature

or degree.

In selecting a margin of safety, EPA has considered

such factors as the nature and severity of the health

effects involved, the size of the sensitive population(s) at

risk, and the kind and degree of the uncertainties that

must be addressed. Given that the “margin of safety”

requirement by definition only comes into play where no

conclusive showing of harm exists, such factors, which

involve unknown or only partially quantitified risks, have

their inherent limits as guides to action. The selection

of any particular approach to providing an adequate mar-

gin of safety is a policy choice left specifically to the

Administrator’s judgment. Lead Industries Association

v. EPA, supra, 647 F.2d at 1161-62.

Section 109(d) of the Act (42 U.S.C. 7409(d)) re-

quires periodic review and, if appropriate, revision of

existing criteria and standards. The process by which

EPA has reviewed the original criteria and standards

for particulate matter under section 109(d) is described

in Sections I.C. and I.D. of this notice.

2. Related Control Requirements

States are primarily responsible for ensuring attain-

ment and maintenance of ambient air quality standards

once EPA has established them. Under section 110 of the

Act (42 U.S.C. 7410), States are to submit, for EPA

approval, State implementation plans (SIPs) that pro-

vide for the attainment and maintenance of such stand-

ards through control programs directed to sources of the

pollutants involved. Other Federal programs provide for

nationwide reductions in emissions of these and other air

pollutants through the Federal Motor Vehicle Control

Program under Title II of the Act (42 U.S.C. 7501 to

7534), which involves controls for automobile, truck, bus,

motorcycle, and aircraft emissions, and through the devel-

opment of New Source Performance Standards under sec-

tion 111 (42 U.S.C. 7411) and National Emission Stand-

ards for Hazardous Air Pollutants under section 112

(42 U.S.C. 7412).

B. Particulate Matter and Original Standards for TSP

“Particulate matter” is the generic term for a broad

class of chemically and physically diverse substances that

exist as discrete particles (liquid droplets or solids) over

a wide range of sizes. Particles originate from a variety

of stationary and mobile sources. They may be emitted

directly or formed in the atmosphere by transformations

of gaseous emissions such as sulfur oxides, nitrogen

oxides, and volatile organic substances. The chemical and

physical properties of particulate matter vary greatly

with time, region, meteorology and source category, thus

complicating the assessment of health and welfare ef-

fects. The characteristics, origins, concentrations, and

potential effects of particulate matter are discussed in

more detail in the staff paper (SP) (EPA, 1982a), in

the revised criteria document (CD) (EPA, 1982b), in

the criteria document addendum (CDA) (EPA, 1986a)

and in the staff paper addendum (SPA) (EPA, 1986b).

The executive summary of the staff paper addendum is

reprinted in Addendum III to this notice.

On April 30, 1971 (36 FR 8186), EPA promulgated

the original primary and secondary NAAQS for particu-

late matter under section 109 of the Clean Air Act. The

reference method for measuring attainment of these

standards is the “high-volume” sampler (40 CFR Part

50, Appendix B), which collects particulate matter up to

a nominal size of 25 to 45 micrometers (nm) (so-called

“total suspended particulate,” or “TSP”). Thus, TSP is

the current indicator for the particulate matter stand-

ards. The existing primary standards for particulate

matter (measured as TSP) are 260 y»g/m*, 24-hour

average not to be exceeded more than once per year, and

75 »g/m*, annual geometric mean. The secondary stand-

ard (measured as TSP) is 150 »g/m', 24-hour average

not to be exceeded more than once per year. The scien-

tific and technical bases for these standards are con-

tained in the original criteria document, Air Quality Cri-

teria for Particulate Matter (DHEW, 1969).

C. Development of Revised Air Quality Criteria for

Particulate Matter

In 1976, as a result of internal Agency review and the

recommendations of a committee of EPA’s Science Ad-

visory Board, EPA decided to revise the existing criteria

document for particulate matter. Because of competing

priorities regarding revision of other criteria documents,

and because of the need to complete additional research

on particulate matter, the process was scheduled to com-

mence in 1979. With the endorsement of the Clean Air

Scientific Advisory Committee (CASAC) of EPA’s Sci-

ence Advisory Board, EPA decided to review and revise

the criteria document for particulate matter concurrently

with that for sulfur oxides and to produce a combined

particulate matter/sulfur oxides (PM/SO.) criteria doc-

ument. On October 2, 1979 (44 FR 56731), EPA an-

nounced that it was in the process of revising the criteria

document and reviewing the existing air quality stand-

ards for possible revisions.

In developing the revised criteria document, EPA has

provided a number of opportunities for review and com-

ment by organizations and individuals outside the

Agency. Three drafts of the revised particulate matter/

sulfur oxide criteria document, prepared by EPA’s En-

vironmental Criteria and Assessment Office (ECAO},

were made available for external review on April 11,

1980 (45 FR 24913), January 29, 1981 (46 FR 9746),

and October 28, 1981 (46 FR 53210). EPA received and

considered numerous and often extensive comments on

each of these drafts. CASAC held three public meetings

to review successive drafts of the document on August

20-22, 1980 (45 FR 5164, August 4, 1980), July 7-9,

1981 (46 FA 31746, June 17, 1981), and November

16-18, 1981 (46 FR 53210, October 28, 1981). These meet-

ings were open to the public and were attended by many

individuals and representatives of organizations who pro-

vided critical reviews and new information for considera-

tion. In accordance with CASAC recommendations made

after the first review meeting, five additional public

meetings were held at which EPA, its consulting authors

and reviewers, and other scientifically and technically

qualified experts selected by EPA discussed the various

chapters of the draft document and suggested ways of

resolving outstanding issues (45 FR 74047, November 7,

1980; 45 FR 78224, November 25, 1980; 45 FR 76790,

November 20, 1980; 45 FR 80350, December 4, 1980;

46 FR 1775, January 7, 1981).

The comments received on the successive drafts of the

revised criteria document were considered in the final

document, issued simultaneously with the proposal of

revisions to the standards. A summary of EPA’s re-

sponses to the comments on the three external review

drafts of the documents is in the public docket (Docket

No. A-82-37). Transcripts of the three CASAC meetings

are also in the docket. In accordance with its established

procedures, CASAC prepared a “closure” memorandum

to the Administrator indicating its satisfaction with the

final draft (December, 1981) of the criteria document

and outlining key issues and recommendations. The

closure memorandum, dated January 29, 1982, stated

that the EPA office that prepared this document was

“responsive to Committee advice as well as to comments

provided by the general public . . .” The closure memo-

randum further stated that the criteria document “ful-

fills the requirements set forth in section 108 of the Clean

Air Act, which requires that the criteria document ‘shall

accurately reflect the latest scientific knowledge useful

in indicating the kind and extent of all identifiable effects

on public health or welfare’ from sulfur oxides and par-

ticulates in the ambient air.” The CASAC closure memo-

randum on the criteria document is reprinted in its en-

tirety in Addendum I to this notice. Following closure,

minor technical and editorial refinements were made to

the criteria document for printing (EPA, 1982b).

10a

A number of scientific and technical issues were raised

during the public review process. With respect to the

particulate matter portions of the criteria document, the

major issues included the relationship among various

measures of particulate matter air quality, the implica-

tions of particle deposition and other studies for selecting

a particulate matter indicator, and the development and

application of criteria for deciding which epidemiological

studies are most appropriate for use in revising air qual-

ity standards. A summary of these and other major scien-

tifie issues, as well as CASAC’s conclusions, is included

in the closure memorandum on the criteria document

(Addendum I).

D. Review of the Standards: Development of Staff Paper

In the evolving process of revising the national am-

bient air quality standards, EPA has found it useful to

prepare a document that helps bridge the gap between

the scientific review of health and welfare effects con-

tained in the criteria document and the judgments re-

quired of the Administrator in setting ambient standards.

This document, known as the staff paper, has become an

important element in the standards review process, pro-

viding an opportunity for public comment on proposed

staff recommendations before they are presented to the

Administrator.

In the spring of 1981, EPA’s Office of Air Quality

Planning and Standards (OAQPS) prepared the first

draft of the staff paper, Review of the National Am-

bient Air Quality Standards for Particulate Matter: As-

sessment of Scientific and Technical Information. This

draft staff paper, based on the then existent draft of tne

revised criteria document, evaluated and interpreted the

available scientific and technical infprmation most rele-

vant to the review of the air quality standards for par-

ticulate matter and presented staff recommendations on

alternative approaches to revising the standards. This

lla

and a second draft of the paper were reviewed at two

CASAC meetings on July 7-9, 1981 (46 FR 31746, June

17, 1981), and November 16-18, 1981 (46 FR 538210,

October 28, 1981). Numerous written and oral comments

were received on the drafts from CASAC, representatives

of organizations, individual scientists, and other inter-

ested members of the public. A summary of major re-

visions made in response to comments on the first draft

is contained in an October 31, 1981 letter to CASAC

(Padgett, 1981). Following the second CASAC meeting,

the staff made further revisions in response to comments

and prepared an executive summary that was received by

CASAC members before preparation of the closure memo-

randum on the staff paper. In January, 1982, EPA re-

leased the final OAQPS staff paper (EPA, 1982a), which

reflects the various suggestions made by CASAC and

members of the public. The January 29, 1982, CASAC

closure memorandum states that the staff paper “has

been modified in accordance with recommendations made

by CASAC,” is consistent with the criteria document, and

provides the Administrator “with the kind and amount of

technical guidance that will be needed to make appropri-

ate revisions to the standard.” This closure memoran-

dum is reprinted in Addendum II to this notice.

A number of major issues were raised during the pub-

lic review process. The more important issues are out-

lined below.

1. Substantial discussion concerned the maximum size

of particles (or particle size fraction) to be used in

measuring particulate matter for regulatory purposes.

Some groups favored retaining TSP as an indicator;

others called for alternative size-specific standards with

nominal “size cuts” (“D,,.”; see discussion in Section

III.A.) of 15 pm, 10 G6mm, 5-7 G6mm, and 2.5 G6mm.

After CASAC closure on the staff paper and criteria doc-

ument, comments were received from one group favoring

a so-called “D,” of 10um (approximately equivalent to a

nominal size cut [D,.] of 6 um).

12a

2. Much attention was focused on selecting the level

of the primary standards and on the question of which

health effects studies were most appropriate for this pur-

pose. Significant criticisms were received on the major

epidemiological studies of particulate matter exposures,

highlighting their limitations for use in standard setting.

In a number of comments, specific suggestions for stand-

ards were made.

3. With respect to secondary standards, most attention

focused on the possible need for a fine [=2.5 G6m) par-

ticle standard designed to protect visibility.

These and other major issues are discussed more fully

in the executive summary of the staff paper and in later

sections of this notice. CASAC’s discussion of these is-

sues and its recommendations are contained in the closure

memorandum on the staff paper (Addendum II).

E. Proposed Revisions to the Standards

On March 20, 1984 (49 FR 10408) EPA proposed a

number of revisions to the primary and secondary par-

ticulate matter standards. The proposed revisions, based

on the revised criteria, included:

(1) Replacing TSP as the indicator for particulate

matter for the primary standards with a new indicator

that includes only those particles with an aerodynamic

diameter less than or equal to a nominal 10 micrometers

(PM,,);

(2) Changing the level of the 24-hour primary stand-

ard to a value to be selected from a range of 150 to 250

pg/m*® and replacing the deterministic form of the stand-

ard, which permitted not more than one observed ex-

ceedance of the standard per year, with a statistical form

that would permit one expected exceedance per year;

(8) Changing the level of the annual primary stand-

ard to a value to be selected from a range of 50 to 65

ypg/m*, and changing the form from an annual geometric

mean to an expected annual arithmetic mean; and

13a

(4) Replacing the current 24-hour secondary TSP

standard by an annual TSP standard selected from a

range of 70 to 90 yug/m*, expected annual arithmetic

mean.

The Administrator expressed an inclination to select

the primary standards from the lower portions of the

above ranges. With respect to the secondary standards,

the Administrator was inclined to select the final stand-

ard from the upper portion of the range, but also called

for comment on the alternative of using PM,, as the

particulate matter indicator for the secondary standards

and making the secondary standards identical in all re-

spects to the primary standards. The proposal notice sets

forth the rationale for these and other proposed revisions

of the particulate matter NAAQS and background infor-

mation related to the proposal.

F. Supplemental Criteria Revisions and Standards Re-

view Following Proposal

Following publication of the proposal, EPA held a pub-

lice meeting in Washington, D.C. on April 30, 1984 to

receive comments on the proposed standards revisions.

A transcript of the meeting has been placed in the public

docket (Docket No. A-82-37). After the close of the orig-

inal public comment period (June 5, 1985), the CASAC

met on December 16-17, 1985 to review the proposal and

to discuss the relevance of certain new scientific studies

on the health effects of particulate matter that had

emerged since the Committee completed its review of the

criteria document and staff paper in January, 1982. A

transcript of this meeting is also available in the Docket.

Based on its preliminary review of these new studies, the

Committee recommended that the Agency prepare sepa-

rate addenda to the criteria document and staff paper for

the purpose of evaluating the relevant new studies and

discussing their potential implications for standard-

setting. The Agency announced its acceptance of these

14a

recommendations on April 1, 1986 (51 FR 11058). On

July 3, 1986, EPA announced (51 FR 24392) the avail-

ability of the external review draft document entitled:

Second Addendum to Air Quality Criteria for Particulate

Matter and Sulfur Oxides (1982): Assessment of Newly

Available Health Effects Information. At the same time,

the Agency announced a supplementary comment period

on the March 20, 1984 proposal to provide the public an

opportunity to comment on the implications of the new

studies and addenda for the final standards. On Septem-

ber 16, 1986, EPA announced (51 FR 32878) the avail-

ability of the draft staff paper addendum entitled Review

of the National Ambient Air Quality Standards for Par-

ticulate Matter: Updated Assessment of Scientific and

Technical Information. CASAC held a public meeting on

October 15-16, 1986 to review both the criteria document

addendum and the staff paper addendum. At this meet-

ing, CASAC members as well as representatives of sev-

eral organizations, provided critical review of both EPA

documents. A transcript of the CASAC meeting has been

placed in the public docket (A-82-37).

The CASAC sent a closure letter on the criteria docu-

ment addendum to the Administrator dated December 15,

1986, which concludes “that this 1986 Addendum along

with the 1982 Criteria Document, previously reviewed by

CASAC, represent a scientifically balanced and defensible

summary of the extensive scientific literature on these

pollutants” (Lippman, 1986b). The closure letter on the

criteria document addendum is reprinted in Addendum I

of this notice. The Committee sent their closure letter

on the staff paper addendum to the Administrator dated

December 16, 1986, stating “The Committee believes that

this document provides you with the kind and amount

of technical guidance that will be needed to make appro-

priate revisions to the standards” (Lippman, 1986c).

The closure letter on the staff paper addendum, which

also discusses major issues addressed by the CASAC and

the Committee’s recommendations concerning these issues,

15a

is reprinted in Addendum II to this notice. The final

addenda to the criteria document (EPA, 1986a) and the

staff paper (EPA, 1986b), which include revisions to

reflect comments from CASAC and the public, are avail-

able from the address listed above. Where there are dif-

ferences between the 1982 Criteria Document and staff

paper and the more recent addenda, the addenda super-

sede the earlier document. The executive summary of the

staff paper addendum is reprinted in Addendum III of

this notice.

II. Summary of Public Comments

The following discussion summarizes in general terms

the comments received from the public and from govern-

mental agencies regarding the proposed revisions to the

indicator, form, averaging times, and levels of the pri-

mary and secondary standards. Many of these comments

had been made previously by the public during public

deliberations on drafts of the criteria document and staff

paper and were reviewed and addressed by EPA in re

visions to those documents. Salient comments on all as-

pects of the proposal and Agency responses to those

comments are summarized by category in Section VI of

this notice. A more detailed description of individual

comments and Agency responses has been entered in the

public docket (No. A-82-37).

A. Comments on 1984 Proposal

Extensive written comments were received during the

original comment period on the proposal, which closed

June 5, 1985. Of some 312 written submissions, 153 were

provided by individual industrial concerns or industry

groups, 93 by State, local, and Federal government agen-

cies and organizations, 32 by environmental and public

interest groups, and 34 by individual private citizens.'

1This numerical distribution of comments in each category

should be compared with caution. For example, the American Iron

l6a

The comments on the key elements of the proposed stand-

ards are summarized below:

(1) Indicator for the Primary Standard: The over-

whelming majority of the comments received on this issue

favcred a size-selective indicator for the PM standard.

Of the 147 written comments received on this issue, 108

supported the PM,, indicator proposed by the Agency.

Most of the remaining comments were in support of al-

ternative smaller particle size indicators including PM,

(28 comments) and PM,., (8 comments). The principal

support for PM, came from mining and related indus-

tries.

(2) Levels of the Primary Standards: Comments on

the proposed levels for the two primary standards were

more polarized than those on the indicator. Most indus-

try comments favored selecting the level of the standards

at the upper end of the proposed ranges or above, while

most of the remaining commenters favored standard

levels at the lower bound of the ranges, and in some cases

lower. Additional comments from individual citizens, en-

vironmental groups, and government agencies urged that

the level of protection afforded by the current particulate

matter standards be maintained or strengthened.

* & * *

B. Comments on Subsequent Notice

As discussed earlier in this notice, EPA announced an

additional public comment period on July 3, 1986 to ad-

dress the implications of new scientific studies on the

health effects of particulate matter [51 FR 24392]. Ap-

proximately 20 additional written submissions were re-

ceived by the close of this comment period on November

and Steel Institute and the American Petroleum Institute submitted

comments on behalf of 63 and 230 individual companies respectively,

in lieu of having each of their member companies send separate

comments. Similarly, comments from interest groups such as

NRDC represent the views of a number of individuals.

Cae eae Aon A edt

ithe inden Pe ol ea

~ Nts

= aca Ab NR ANA em CA eS me IA OY ay n

17a

17, 1986, 17 of which were provided on behalf of indus-

try groups or companies, 2 from environmental groups,

and 1 from a state agency. Much of the material related

to evaluations of specific studies and their treatment in

the staff paper addendum. The industry comments, which

included submissions from consulting scientists and ana-

lysts, generally found that the new studies suffered from

deficiencies that preclude placing much weight on them

in standard setting. These commenters concluded that

their original recommendations (summarized above)

with respect to the standards remained valid. The two

environmental groups felt that the findings in these new

studies necessitated standards below the lower bounds of

the proposed ranges.

III. Rationale for the Primary Standards

In selecting primary standards for particulate matter,

the Administrator must specify: (1) the particle size

fraction that is to be used as an indicator of particulate

pollution; (2) the appropriate averaging times and

form(s) of the standards; and (3) the numerical levels

of the standards. These specifications must be considered

collectively in evaluating the margin of safety afforded by

particulate matter standards. Based on the assessments

of relevant scientific and technical information in the

criteria document and addendum, the staff paper and

staff paper addendum (hereinafter “SP” and “SPA,”

respectively) outline a number of key factors to be con-

sidered in making decisions in each of these areas (SP,

Section VI; SPA, Section IV). Both the staff and

CASAC made recommendations to focus consideration on

a discrete range of options. In most respects, the Ad-

ministrator has adopted the recommendations and sup-

porting reasons contained in the staff paper and adden-

dum and the CASAC closure statements (Friedlander,

1982; Lippman, 1986c). Rather than reiterating those

discussions at length, the following discussion of the

standards revisions focuses primarily on those considera-

18a

tions that were most influential in the Administrator’s

selection of particular options, or that differ in some re-

spect from considerations that influenced the staff and/or

CASAC recommendations.

A. Pollutant Indicator

Based on the staff assessment of the available scien-

tific information, EPA concludes that (1) a separate

particulate matter standard (as opposed to a combination

standard for particulate matter and SO.) remains a

reasonable public health policy choice, and (2) given cur-

rent scientific knowledge and uncertainties, a size-specific

(rather than chemical-specific) indicator should be used.

In assessing the information in the criteria document, the

staff reached several conclusions summarized here (see

SP, pp. 71-75) :

(1) Health risks posed by inhaled particles are influ-

enced both by the penetration and deposition of particles

in the various regions of the respiratory tract, and by

the biological responses to these deposited materials.

Smaller particles penetrate furthest in the respiratory

tract. The largest particles are deposited in the extra-

thoracic (head) region with somewhat smaller particles

depositing in the tracheobronchial region. Still smaller

particles can reach the deepest portion of the lung, the

alveolar region.

(2) The risks of adverse health effects associated with

deposition of typical ambient fine and coarse particles?

in the thorax (tracheobronchial and alveolar regions of

the respiratory tract) are markedly greater than those

associated with deposition in the extrathoracic (head)

region. Maximum particle penetration to the thoracic re-

gion occurs during oronasal or mouth breathing. .

(3) The size-specific indicator for primary standards

should represent those particles small enough to penetrate

2 Particles in ambient air usually occur in two somewhat over-

lapping size distributions, fine (diameter less than 2.5u.m) and

coarse (diameter larger than 2.5 pm). The two size fractions tend

to have different origins and composition (SP, Appendix D).

ON ON. wr coe tiene a! tell

ee Senne ks ee at © eee

19a

to the thoracic region (both the tracheobronchial and

alveolar regions). The risks of adverse health effects

from extrathoracic deposition of typical ambient par-

ticulate matter are sufficiently low that particles deposit-

ing only in that region can safely be excluded from the

indicator.

Considering these conclusions together with other infor-

mation on air quality composition, respiratory tract depo-

sition and health effects, the need to provide protection

for sensitive individuals who may breathe by mouth and/

or oronasally, and the similar convention on particles

penetrating the thoracic region recently adopted by the

International Standards Organization (ISO, 1981), the

staff recommended that the size-specific indicator include

particles of diameters less than or equal to a nominal 10

um “cut point.’”’* The factors considered in the original

staff recommendations for a 10 um cut point are outlined

in the staff paper (SP, pp. 75-79). This indicator is re-

ferred to as “thoracic particles” (TP) in the 1982 staff

paper, is now generally referred to as “PM,,.” Such an

indicator is conservative with respect to health protection

in that it includes all of the particles small enough to

penetrate to the sensitive alveolar region, and includes

approximately the same proportion of larger particles as

would be expected to reach the tracheobronchial region.

It places substantially greater emphasis on controlling

smaller particles than does a TSP indicator, but does not

completely exclude larger particles from all control.

The assessment of more recent information on respira-

tory tract deposition in the criteria document and staff

3The more precise term is 50% cut point or 50% diameter

(D,,). This is the aerodynamic particle diameter for which the

efficiency of particle collection is 50%. Larger particles are not

excluded altogether, but are collected with substantially decreasing

efficiency and smaller particles are collected with increasing (up to

100%) efficiency. Ambient samples with this cut point provide a

reliable estimate of the total mass of suspended particulate matter

of aerodynamic size less than or equal to 10ym. See additional dis-

cussion regarding the Federal Reference Method in section V below

and in the accompanying notice revising 40 CFR Part 53.

20a

paper addenda reinforces the conclusions reached in the

original staff asesssment. In particular, the staff paper

addendum found that: (1) the recent data do not pro-

vide support for an indicator that excludes all particles

larger than 10 »m in diameter;* (2) the analysis used

to support an alternative indicator with a nominal size

cut of 6 G6mm (Swift and Proctor, 1982) significantly

underestimated thoracic deposition of particles larger

than 6 »m in diameter under natural breathing condi-

tions; (3) the PM,, indicator generally includes a simi-

lar or larger fraction of the range of particles that can

deposit in the tracheobronchial region, although it ap-

pears to be somewhat less conservative in this regard

than previously thought with respect to large (G6=10

um) particle deposition under conditions of natural

mouthbreathing; and (4) the studies of tracheobronchial

deposition generally involved adult subjects; recent in-

formation indicating even greater tracheobronchial depo-

sition of particles in children than in adults provides an

additional reason for an indicator that includes particles

capable of penetration of the tracheobronchial region

(SPA, p. 36). Consideration of these and the earlier con-

clusions led the staff to reaffirm its recommendation for

a PM,, indicator (SPA, pp. 36-37). The CASAC also

restated its recommendation for PM,, in its review of the

proposal and the closure letter to the Administrator

(Lippmann, 1986 a, ¢c).

The Administrator accepts the recommendations of the

staff and CASAC and their underlying rationale and has

decided to replace TSP as the particle indicator for the

primary standards with a new indicator that includes

only those particules less than a nominal 10 »m in di-

ameter, as specified in the Federal Reference Method

(Appendix J to 40 CFR Part 50) being promulgated to-

{

4 The American Mining Congress (AMC, 1982) had recommended

such an indicator, with a “D,” of 10,m. EPA estimated that the

“D,,.” of this indicator would be 6 ym.

21a

day. In defining the standards for particulate matter,

this new indicator is termed PM...

* * * o

C. Level of the Standards

The original staff paper and CASAC recommendations

set forth a framework for determining the levels for the

proposed particulate matter standards that would pro-

tect public health with an adequate margin of safety.

The discussion that follows relies heavily on that frame-

work and on the supporting material in the staff paper

and its addendum as well as the CASAC closure letters.

The essential steps in this framework are summarized

here.

1. Assessment of the quantitative epidemiological

studies.

The criteria document and its addendum identify a

small number of community epidemiological studies that

are useful in determining concentrations at which par-

ticulate matter is likely to affect public health. The staff

used these quantitative studies to examine concentration-

response relationships and to develop numerical “ranges

of interest” for possible PM,,, standards.

A number of uncertainties associated with use of these

studies must be considered in selecting an appropriate

margin of safety. As discussed in the staff paper and

the criteria document, and the addenda to those docu-

ments, epidemiological studies are generally limited in

sensitivity and subject to inherent difficulties involving

confounding variables. Moreover, many of the quantita-

tive studies were conducted in times and places where

pollutant composition may have varied considerably from

current U.S. atmospheres. Most also have used British

Smoke * or TSP as particle indicators. None of the pub-

5 British Sméke (BS) is a pseudo-mass indicator related to small

particle (aerodynamic diameter less than a nominal 4.5 ,m) dark-

ness. This particulate matter indictaor was widely used in British

and other European studies. See the criteria document for a more

detailed treatment of BS (CD, pp. 1-88 to 1-90 and 14-8 to 14-11).

22a

lished studies used the proposed PM,, indicator. Thus,

assumptions must be used to convert the various results

to common (PM,,) units (SP, pp. 96-100; SPA pp. 9-11).

2. Identification of additional margin of safety con-

siderations.

The criteria document identifies an additional substan-

tial body of scientific literature that, while not providing

reliable concentration-response relationships for ambient

exposures, does provide important qualitative insights

into the health risks associated with human exposure to

particles. This literature includes both quantitative and

qualitative epidemiological studies, controlled human ex-

posure experiments, and animal toxicological studies.

The staff assessed this literature to identify additional

factors and uncertainties that should be considered in

selecting the most appropriate margin of safety (SP, pp.

100-101; 107-111, SPA pp. 52-53; 59).

3. Selection of the levels that might be considered to

provide an adequate margin of safety.

The intent of the margin of safety requirement was to

direct the Administrator to set air quality standards at

pollution levels below those at which adverse health ef-

fects have been found or might be expected to occur in

sensitive groups. Experience with the requirement has

shown that the scientific data are often so inconclusive

that is is difficult to identify with confidence the lowest

pollution level at which an adverse effect will occur.

Moreover, in cases such as the present one, the evidence

suggests that there is a continuum of effects, with the

risk, incidence, or severity of harm decreasing, but not

necessarily vanishing, as the level of pollution is de-

creased.

In the absence of clearly identified thresholds for health

effects, the selection of a standard that provides an ade-

quate margin of safety requires an exercise of informed

judgment by the Administrator. The level selected will

depend on the expected incidence and severity of the po-

tential effects and on the size of the population at risk,

23a

as well as on the degree of scientific certainty that the

effects will in fact occur at any given level of pollution.

For example, if a suspected but uncertain health effect is

severe and the size of the population at risk is large, a

more cautious approach will be appropriate than would

be if the effect were less troubling or the exposed popula-

tion smaller.

EPA staff originally recommended a range of potential

standards for the Administrator’s consideration (SP, pp.

111-114). The recommended range was below the levels

at which the staff, with the concurrence of CASAC, had

concluded from the available data that adverse health

effects were “likely,” but in the domain where the data

suggested that such effects were “possible.” The Admin-

istrator proposed refined ranges of standard levels that

were based on the original staff and CASAC recommen-

dations. After consideration of the new scientific evi-

dence contained in the criteria document addendum, the

staff revised its recommendations for ranges of stand-

ards (SPA, pp. 60-62). The Administrator has consid-

ered the revised assessments and the recommendations

of CASAC (Lippmann, 1986b) in making his final de-

cision on the standard levels. The rationales for the

levels of the 24-hour and annual standards are presented

below.

1. 24-Hour Standard

The revised staff assessment of the short-term epidemi-

ological data is summarized in Table 1; particulate mat-

ter levels are expressed in both the original (British

Smoke [“BS”] or TSP) and PM,, units. The “effects

likely” row in Table 1 denotes concentration ranges de-

rived from the criteria document and its addendum at or

above which a consensus judgment suggests greatest cer-

tainty that the effects studied would occur, at least under

the conditions that occurred in the original studies. In

the “effects possible” range, the staff found credible scien-

tific evidence suggesting the existence of adverse health

effects in sensitive populations, but substantial uncer-

tainty exists regarding the conclusions to be drawn from

such evidence.

24a

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26a

The data do not provide evidence of clear thresholds in

exposed populations. Instead, they suggest a continuum

of response for a given number of exposed individuals

with both the likelihood (risk) of any effects occurring

and the extent (incidence and severity) of any potential

effect decreasing with concentration. This is particularly

true for the statistical analyses of daily mortality in

London. Substantial agreement exists that wintertime

pollution episodes produced premature mortality in elderly

and ill populations, but the range and nature of associa-

tion provide no clear basis for distinguishing any par-

ticular lowest “effects likely” levels or for defining a con-

centration below which no association remains. The re-

cent lung function studies in children also provide

evidence of effects at concentrations in the range listed in

Table 1, but the relationships are not certain enough to

derive “effects likely” levels for PM,,. The lung function

studies do, however, suggest levels below which detectable

functional changes are unlikely to occur in exposed popu-

lations. Following CASAC recommendations, the staff

used the combined range listed in the “effects possible”

row as a starting point for developing alternative stand-

ards.

The original range proposed by the Administrator,

drawn from the 1982 staff analysis, was 150 to 250 yug/

m’ PM,,, 24-hour average with no more than one expected

exceedance per year. The lower bound of this range was

derived from the original assessment of the London mor-

tality studies. As a result of its updated assessment of

reanalyses of the London mortality and more recent U.S.

morbidity studies, the staff reduced the level of the lower

bound of the range of interest to 140 »g/m* (SPA, 51),

while noting that the difference between it and original

lower bound (150 yg/m*) is within the range of un-

certainty associated with converting the morbidity study

results from TSP to PM,.,. -

As indicated in Table 1, the study of Lawther et al.

(1970) judged to provide evidence that health effects are

27a

likely at particulate matter concentrations above 250 pg/

m* (as BS). The effects observed in this study (related

to aggravation of bronchitis) are of concern both because

of their immediate impact and because of the potential

for inducing longer-term deterioration of health status in

a significant sensitive group. There were approximately

G.5 million bronchitics in the U.S. in 1970 (DHEW,

1973). Based on the uncertain conversion between smoke

and PM,, outlined in Table 1, the lowest “effects likely”

level derived from the Lawther study (259 »pg/m* as BS)

should be in the range of 250 to 350 pg/m’*, in PM,, units.

The assessment of this study formed the basis for the

upper bound of the range of PM,, standards proposed by

the Administrator in 1984. Considering this study alone,

a PM,, standard of 250 »g/m* might appear to contain

some margin of safety, even for the sensitive bronchitics

studied, because it incorporates a conservative British

Smoke/PM,, conversion factor and because of differences

between exposure conditions in the British study and cur-

rent U.S. air quality (SP, pp. 100-101). Because bron-

chitics are identified as a group particularly sensitive to

particulate pollution, a standard of 250 »pg/m* (as PM,,)

also might provide some margin of safety for other, less

sensitive, groups. Nevertheless, this study of bronchitics

in London has inherent limitations in sensitivity that pre-

clude derivation of unequivocal “effects of thresholds” at

250 »g/m* as BS, and by extension PM,,. The criteria

document notes that associations between pollution and

health status persisted at lower BS concentrations in

selected, more sensitive individuals. Although the lead

author of the study object’ to attaching any importance

to these latter findings (Lawther, 1986), EPA, with

CASAC concurrence, finds no basis for asserting that this

study demonstrates a population threshold at 250 p»pg/m’*.

In evaluating the margin of safety for a 24-hour stand-

ard, it is also important to consider the London mortality

studies. A standard at the upper portion of the proposed

28a

range (250 ug/m*) would be well below the levels (500

to 1000 »g/m* as BS) of the historical London episodes

in which the scientific consensus indicates that pollution

was responsible for excess mortality (CD, Table 14-7).

The portions of the population at greatest risk of pre-

mature mortality associated with particulate matter ex-

posures in such episodes include the elderly and persons

with pre-existing respiratory or cardiac disease. Although

the extent of life shortening (days, weeks, or years) can-

not be specified, the seriousness of this effect strongly

justifies a margin of safety for it (below the consensus

effects levels) that is larger than that warranted for the

effects on bronchitics.

The staff assessment of the several reanalyses of Lon-

don mortality suggests, however, that the risk of pre-

mature mortality to sensitive individuals extends to

concentrations substantially lower than those which oc-

curred in the “episodes.” The more recent analyses

(Mazumdar et al., 1982; Ostro, 1984; Shumway et al.,

1983) provide no objective support for a population

threshold below which such a risk no longer exists. Al-

though the risk to individuals may be small at concentra-

tions of 250 »g/m* and below, the number of people ex-

posed to lower concentrations given current U.S. levels is

substantially larger than the number exposed to higher

levels (SPA, Table 2-1). The increased number of indi-

viduals exposed increases the risk that effects will occur

in the total population exposed.

Differences in the composition of particles and gases

among U.S. cities and between current conditions in the

U.S. and those in London at the time the mortality and

morbidity data were gathered add to the complexity of

assessing the risk associated with particulate matter in

the U.S. In the case of the mortality studies, however,

the staff found that at least one of the more recent studies

(Ozkaynak and Spengler, 1985) provides qualitative sup-

port for an association between daily mortality and par-

VO Th nd Myre aide ence erwes Cte ahs

;

29a

ticle concentrations in nearly contemporary U.S. atmos-

pheres (SPA, pp. 48-44).

The 1982 assessment of the mortality studies and re-

lated factors prompted the Administrator to consider

standard levels that extended from 250 »g/m* down to

the lower bound of the original staff range of interest

(150 »g/m*) and even lower. The more recent analyses

of the London mortality data provide additional evidence

that serious adverse health effects may occur at particu-

late concentrations below 250 »g/m*. These analyses have

addressed a number of the uncertainties associated with

the earlier studies, and have reinforced the Adminis-

trator’s concern that a 24-hour standard at the upper end

of the proposed range may not provide an adequate mar-

gin of safety. However, given the uncertainties in con-

verting from BS to PM,, measurements, particularly at

lower concentrations, and the possible differences in par-

ticulate composition between London at the time the data

were gathered and the contemporary U.S., it is difficult

to use these studies to set a precise level for a PM,,

standard (SPA, pp. 49-51).

Given these difficulties, it is important to examine con-

temporary studies that utilize gravimetric measurements

of particulate concentrations. The staff found the studies

of Dockery et al. (1982) and Dassen et al. (1986) to be

particularly useful. The Dockery study observed physio-

logically small but statistically significant decreases in

lung function in a group of children exposed to peak

PM,, levels of 140-250 »g/m*. The decrements persisted

for 2-3 weeks following the exposures. The study also

suggested the possibilty of larger responses in a subset

of the children, including those with existing respiratory

symptoms. The Dassen study recorded similar decrements

in children in the Netherlands following exposure to PM,,

levels estimated at 200 to 250 ug/m*, but no observable

effects two days after exposure to PM,, levels estimated

at 125 »g/m*. The particle composition, at least in the

30a

Dockery study, is more representative of contemporary

U.S. cities and the associated aerometry provides a more

reliable estimate of PM,, levels than do the measurements

used in the London studies. It is reasonable to expect

that the effects observed (small reversible reductions in

lung function in children) are, in most cases, more sen-

sitive to air pollution than those observed in the London

studies. These effects are, of themselves, of uncertain

significance to health, but might be associated with ag-

gravation of respiratory symptoms in children with pre-

existing illness (SPA, p. 47). Long-term examination of

respiratory health in the same community studied by

Dockery et al. (1982) suggests that the children in that

community have a higher incidence of respiratory illness

and symptoms than children in communities with lower

particle levels, but the data show no evidence for any

persistent reduction in lung function (Ware et al., 1986).

Uncertainties with respect to the effects of other pollut-

tants (e.g., SO.), the consistency of the changes, and ex-

posures preclude specifying unequivocal “effects likely”

levels based on this study. The staff assessment therefore

suggests that short-term lung function effects in children

are possible across a range of 140-250 »g/m* or more as

PM,, (SPA, p. 50).

In making a decision on a final standard level, the

Administrator also considered information from the more

qualitative studies of PM assessed by the staff (SP, pp.

101-103; SPA, pp. 52-53). These suggest increased risks

for sensitive groups (asthmatics) and risks of potential

effects (morbidity in adults) not demonstrated in the

more qualitative epidemiological literature. The quali-

tative studies do not provide clear information on effects

levels, but do justify consideration of effects of particu-

late matter that have not been sufficiently investigated.

Based on the scientific assessment at the time, the Ad-

ministrator in 1984 expressed an inclination to select a

24-hour level from the lower portion of the proposed

3la

range of 150-250 »g/m*. The present Administrator finds

that the updated scientific assessment supports the origi-

nal inclination and, if anything, suggests an even wider

margin of safety is warranted. The recent analyses of

daily mortality are of particular concern in this regard.

The Administrator has, therefore, decided to set the final

standard at the extreme lower bound of the range origi-

nally proposed; that is, at 150 »g/m*. This standard pro-

vides a substantial margin of safety below the levels at

which there is a scientific consensus that particulate mat-

ter causes premature mortality and aggravation of bron-

chitis. Such a margin is necessary because of the serious-

ness of these effects and because of the recent analyses of

daily mortality that suggest adverse effects may occur

at particulate matter levels well below the consensus

levels. The standard is in the lower portion of the range

where sensitive, reversible physiological responses of un-

certain health significance are possibly, but not definitely,

observed in children. Using a conservative assessment of

lung function/particle relationship from Dockery et al.,

a change in concentration from background levels (~20

pg/m*) to 150 »zg/m* would produce lung function

changes of at most 10 to 15% in less than 5% of ex-

posed children (SPA, p. 48). Based on the results of

Dassen et al. (1986), it appears unlikely that any func-

tional changes would be detected one or two days follow-

ing such exposures (SPA, p. 50). Thus, the maximum

likely changes in lung function appear to present little

risk of significant adverse responses. Standards set at a

somewhat higher level would, however, present an un-

acceptable risk of premature mortality and allow the pos-

sibility of more significant functional changes. Further-

more, a standard level of 150 »g/m* is fully consistent

with the recommendations of CASAC on the 24-hour

standard (Lippman, 1986c).

2. Annual Standard

The updated staff assessment of important long-term

epidemiological data is summarized in Table 2. Long-

32a

term epidemiological studies are subject to additional con-

founding variables that reduce their sensitivity and make

their interpretation more difficult than that of short-term

studies. The “effects likely” levels are derived from the

criteria document, but again, no clear thresholds can be

identified for all effects categories. Evidence exists of

effects at lower levels—the “effects possible levels”—but

the evidence is inconclusive and effects are difficult to

detect in the available epidemiological studies.

33a

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34a

Based on a recent assessment of PM,,/TSP ratios in

areas with elevated TSP levels, the updated staff assess-

ment revised the “effects likely” levels from the Ferris

et al. (1973) study to 80 to 90 »g/m* as PM,, (SPA, p.

58). Because of limitations in sampling duration as well

as the conversion to PM,,, this estimate is particularly

uncertain. As indicated in the table, effects are possible

at lower concentrations. Of greatest concern is the pos-

sibility of long-term deterioration of the respiratory sys-

tem in exposed populations, the potential for which is in-

dicated by lung function (mechanical pulmonary) changes

and increased incidence of respiratory disease. One set

of studies (Ferris et al., 1973, 1976) provides some evi-

dence for a “no observed effects” level for these effects

at or below 60 to 65 »g/m* (130 »pg/m* as TSP) while

another study (Bouhuys et al., 1978), suggests some pos-

sibility of symptomatic responses in adults at long-term

median levels at or below about 50 to 55 »g/m* as PM...

The importance of these symptomatic responses, which

were unaccompanied by lung function changes, to long-

term respiratory health is unclear.

The most important recent study of long-term effects is

an ongoing examination of six U.S. cities (Ware et al.,

1986). The study indicates the possibility of increased

respiratory symptoms and illnesses in children at multi-

year levels across a range of 40 to over 58 »g/m* as PM.,,,

but found no evidence of reduced lung function at such

concentrations. This study did not find similar gradients

in symptoms and illness within some of the cities, which

had somewhat smaller localized pollution gradients. The

results of a separate series of studies of long and in-

termediate term (2 to 6 weeks) exposures in a number of

U.S. metropolitan areas (Ostro, 1987 ; Hausman et al.,

1984) are more supportive of the possibility of effects

within cities (respiratory related activity restrictions in

adults) at comparable U.S. exposure levels. The results

of these more recent studies are generally consistent with

the earlier U.S. studies listed in Table 2 (SPA, 57). In

en dt ee eet

lee na ‘etauaintndls

35a

particular, the finding of symptomatic responses in chil-

dren with no change in lung function (Ware et al., 1986)

is consistent with similar findings in adults (Bouhuys et

al., 1973) at estimated long-term PM,, levels down to 50

»g/m*. However, the information available to support

the existence of significant adverse effects at annual

PM,, levels below 50 »g/m*—especially when 24-hour

levels are maintained below 150 »g/m*—is quite limited

and uncertain.

Because of the uncertainties in (SP, pp. 104-110; SPA,

54-59), as well as the limited scope and number of, these

long-term quantitative studies, it is particularly impor-

tant to examine the results of qualitative data from a

number of epidemiological, animal, and ambient particle

composition studies when evaluating what constitutes an

adequate margin of safety for an annual standard. These

studies justify concern for serious effects not directly

evaluated in the studies listed in Table 2. Such effects

include damage to lung tissues contributing to chronic

respiratory disease, cancer, and premature mortality

(SP, pp. 109-111). Substantial segments of the popula-

tion may be susceptible to one or more of these effects

(SP, p. 46). Although the qualitative data do not pro-

vide evidence for major risks of these effects at current

annual particulate matter levels in most U.S. cities, the

Administrator believes that the seriousness of the poten-

tial effects and the large population at risk warrant cau-

tion in setting the standard.

Based on the then current scientific assessment, the

Administrator proposed in 1984 to select the annual

standard level from a range of 50 to 65 »g/m*. In the

proposal, the Administrator favored a standard in the

lower portion of the range. The more recent evidence,

although subject to substantial uncertainty, serves to re-

inforce this inclination. In light of the updated assess-

ment and in accordance with the recommendation of

CASAC, the Administrator has decided to set the level

of the annual standard at the lower bound of the original

pe 36a

range, 50 »g/m*, expected annual arithmetic mean. This

standard provides a reasonable margin of safety against

the serious effect of long-term degradation in lung func-

tion, which has been judged likely at estimated PM,,

levels above 80-90 »g/m° and for which there is some

evidence at PM,, levels above §0 to 65 »g/m*. Such a

standard also provides reasonabie pretection against the

less serious symptomatic effects for which some studies

provide evidence at PM,, levels down to 50 xg/m*. Al-

though some small risk of increased respiratory symptoms

may exist at this concentration, the available data are

currently inconclusive on this point. Moreover, the staff

and CASAC have recommended that the combined pro-

tection afforded by both 24-hour and annual standards

be considered in selecting the final standard level. In this

regard, analyses of air quality data show that imple-

mentation of the 24-hour standard will substantially re-

duce annual levels in a number of areas to below 50

ug/m*, adding to the protection afforded by the annual

standard in areas with higher 24-hour peak to mean

ratios (SPA, p. 61; Freas, 1986). Based on the present

evidence with respect te risks associated with annual ex-

posures, the Administrator finds that the annual and 24-

hour standards announced today provide an adequate

margin of safety.

= * * *

VI. Summary of Salient Public Comments and

Agency Responses

An overview of public comments on the major aspects

of the March 20, 1984 proposal are presented in Section

II. The most important comments on specific issues are

categorized and summarized below together with Agency

responses. A more comprehensive compilation of com-

ments and Agency responses is contained in a separate

Response to Comments Document that has been placed in

the Docket (No. A-82-37).

“4. Raedins

37a

A. Health Effects Criteria and Selection of the Primary

Standards

1. Indicator for the Primary Standards

Comments: PM, rather than PM,, should be used as

the indicator for the primary standards because PM,

more accurately reflects particle deposition in the thoracic

regions, provides an ample margin of safety in protecting

health, and puts less emphasis on coarse particles that are

relatively inert than does PM...

Agency Response: EPA considered the major analysis

(Swift and Proctor, 1982) and preliminary arguments

(AMC, 1982) in support of a PM, indicator in develop-

ing the 1984 proposal. Although EPA deferred judgment

pending additional analysis and review, the decision to

propose PM,, and not PM, was based, in part, on reserva-

tions concerning the PM, indicator. The likelihood that

the available data from mouthpiece studies overstated

thoracic deposition during “natural” breathing was rec-

ognized in a qualitative sense by CASAC icf. July 1981

transcript, p. 581; Docket No. A-82-37) and presented as

one reason for recommending PM,, rather than PM,, or

TSP as an indicator. The 1982 staff paper re-

flected this argument in recommending 10 »m rather

than 15um as the cutpoint for the indicator (SP, pp.

76-77). The criteria document addendum points out that

assumptions used in the quantitative analyses used to

support PM, (Swift and Proctor, 1982) appear to under-

estimate thoracic particle deposition; this underestima-

tion would reduce any margin of safety associated with

an indicator derived from these data. Extension of the

Swift and Proctor analysis itself suggests that apprexi-

mately 10 to 20% of 10 »m partcles could penetrate to

the thoracic region, rather than the 0% penetration im-

plied by some commenters who argued for a “D,” at 10

um.

The Swift and Proctor analysis as well as several more

recent analyses and experimental studies of particle depo-

38a

sition are reviewed in the criteria document and staff

paper addendum. The more recent assessments tend to

support the original proposal of PM,,. The criteria docu-

ment addendum compares the work of Miller et al.

(1986), using the more recent deposition data, with the

Swift and Proctor analysis and confirms that the latter

understates deposition of particles larger than 6 um in

individuals who habitually breathe through the mouth.

The more recent data also show some fraction of par-

ticles of 10 »m and larger can penetrate as far as the

alveolar region (CDA, Figure 2-1). The risk associated

with deposition of insoluble coarse particles in this region

is of particular concern because of slow clearance time

(CPA, p. 2-6). Although removal in the tracheobronchial

region is more rapid, deposition of coarse particles in the

tracheobronchial region may be associated with broncho-

constriction and alteration of clearance mechanisms (SP,

Table 5-2). The 1982 staff paper took these factors into

account in the original recommendation for a 10 »m in-

dicator that included all of the fine and a portion of the

coarse fraction.

After considering these updated assessments, the EPA

staff reaffirmed its original recommendation of PM,, as

an indicator for the standards (SP, p. 32). In reviews of

the March 20, 1984 proposal and of the criteria document

and staff paper addenda, the CASAC also reaffirmed its

recommendation for PM,, as an indicator (Lippman 1986

a,c). The majority of public comments on this issue also

favored PM...

In summary, EPA finds that the presently available

record clearly favors the PM,, indicator over the alterna-

tive PM, indicator.

Comments: Some commenters suggested that while

PM,, represents an improvement over TSP, the fine frac-

tion (<2.5 um) is of relatively greater concern to health

than the coarse fraction (2.5 to 10 um). Such comment-

a Oe A Gre te PA

39a

ers suggest that a PM.., standard is needed—in addition

to or, in some comments, instead of a PM,, standard.

Agency response: The possibility of a fine particle in-

dicator for the primary standard was examined in the

staff paper (pp. 68-70). This suggestion is based in part

on the recognition that ambient particle mass and volume

are distributed such that a rough division “minimum”

at about 1 to 3 »m separates the “fine” (smaller) and

“coarse” fractions. Each fraction has somewhat distinct

chemical and physical properties and sources. The staff,

however, noted a number of difficulties in using fine par-

ticles (less than a nominal 2.5 um) alone instead of PM,,

as the indicator for the primary standards. These in-

clude:

(1) Substantial overlap can occur between the two

modes and in some cases the division minimum can dis-

appear. Moreover, despite the differing origins and

chemistries of the modes, each is chemically heteroge-

neous. The respiratory tract, in effect, alters the ambient

distribution, with a mixture of fine and coarse modes

being deposited in both the tracheobronchial and alveolar

regions. Indeed, the 2.5 um “cut” is within the size range

of maximum efficiency for alveolar deposition (2 to 4

um). The mixing of these size fractions in the respira-

tory tract and the heterogeneity within each fraction

therefore blurs the distinction between the fractions in

terms of health effects.

(2) Coarse dusts have been associated with responses

such as bronchoconstri¢tion, altered clearance and alveo-

lar tissue damage (SP, Table 5-2). Given current infor-

mation, it would be premature to ascribe all of the effects

in the British, U.S., and other epidemiological studies to

the fine fraction, or to any single chemical entity within

that fraction.

EPA believes that a separate fine particle standard in

addition to the PM,, standard is not warranted for the

following reasons:

40a

(1) Fine mass typically comprises on the order of 40

to 70% of PM,,. Therefore, the PM,, standards provide

substantial limits on fine mass, and

(2) The limited epidemiological data presently avail-

able must provide the principal basis for any particulate

matter standard. Because these data do not separate the

effects of fine and coarse fractions, it is most reasonable

to use these data to support a single set of standards.

(3) To the extent that emerging information suggests

additional protection may be necessary, it may be more

appropriate to consider the addition of chemical-specific

(e.g., acid aerosols) standards rather than a fine particle

standard in future primary standard revisions.

2. Interpretation of Community Epidemiological

Studies

Comments: A number of commenters took issue with

EPA’s interpretation of the various analyses of London

mortality data. These commenters suggest that (a) the

London data can be used to show only an association of

excess mortality with high concentrations of pollution dur-

ing unique episodes in which BS and SO, levels exceeded

500 to 1000 »g/m*, (b) a number of the analyses suffer

from methodological flaws precluding valid conclusions,

pollution levels (e.g., <250 ug/m*) or that there is a

continuum of association with no identifiable threshold is

not supportable, (d) the results of Mazumdar et al.

(1982) and Ostro (1984) are more consistent with the

hypothesis that particulate matter is acting as a surro-

gate for some other causal agent rather than as a causal

agent itself, and (e) it is biologically implausible that

mortality could be affected by particulate matter at levels

below those shown by Lawther et al. (1970) to produce

morbid effects in sensitive populations.

Agency Response: EPA’s assessment of the various

London mortality analysis is discussed at length in the

eee hee

Nee De eee ee ee ee

OLR OMA Blt Laon?

4la

criteria document, the staff paper, and the addenda to

these documents. The 1982 criteria document found that

in the context of historical London exposures, these data

indicate clear increases in daily mortality occurred with

BS and SO, concentrations in excess of 1000 »g/m* with

some indications of likely increases in daily mortality at

levels of both pollutants in the range of 500 »g/m* or

more (CD, Table 14-7). These original conclusions on

likely effects levels, based largely on the Martin and Brad-

ley (1960) and Ware et al. (1981) analyses, appear rea-

sonably consistent with the original assessment of these

data by the original British investigators and the 1969

criteria document. From the re-examination of these data

by Ware et al. (1981) and the analysis of subsequent

London winters by Mazumdar et al. (1981), the criteria

document also concluded small increases in daily mortality

might occur at leveis below 500 »g/m*. The more recent

analyses of these data by Mazumdar et al. (1982), Ostro

(1984), and Shumway et al. (1983) all serve to rein-

force the possibility that effects were associated with par-

ticulate matter at concentrations below 500 p»g/m*. A

number of commenters, however, including some of the

original British investigators (Holland et al., 1985), ob-

ject to this latter suggestion.

EPA has carefully examined these studies and the var-

ious criticisms of them submitted as comments on the

proposal. In order to respond fully to these criticisms,

EPA conducted more sophisticated reanalyses of the

original London data to further determine the degree of

reliance that can be placed on the published results

(Schwartz and Marcus, 1986, CDA, Appendix A). Each

of these studies does suffer from limitations and uncer-

tainties delineated in EPA’s updated asesssment (SPA

pp. 17-23; 34-44); these limitations preclude definitive

conclusions with respect to causality as well as identifica-

tion of clear “no observed effects’ levels. Nevertheless,

EPA maintains its original interpretation, supported by

its external science advisors, that these data at least sug-

424

gest the possibility of effects of particulate matter at BS

levels as low as 150 »g/m* and possibly even lower. None

of the difficulties in statistical methodology or alternative

mechanisms cited by commenters provide an adequate ex-

planation for the consistent finding of association be-

tween particulate pollution and mortality at levels be-

low 500 »g/m* (as BS). The association was found for

the majority of 14 winters (analyzed individually) span-

ning a period when pollution in London and indoor heat-

ing practices showed marked changes, and including win-

ters in which BS levels did not exceed 250 pg/m*. The

relative consistency of the results from year-to-year de-

spite these changes suggests that the observed effect is

not explained by indoor air pollution or by long-term

demographic shifts in the population. The findings were

consistent among different investigators, and persisted

after taking SO., temperature, and other weather vari-

ables into account, and after correcting for autocorrela-

tion structure.

The principal arguments for the suggestion by some

(including Mazumdar et al., 1982) that smoke may be

acting as a surrogate for some more toxic pollutant or

related non-pollution variable are: (1) The coefficients

in the regression equations appear to increase with de-

creasing pollution across the 14 winters, (2) surrogate

behavior is commonly observed in statistical analyses,

(3) the work of Lawther suggests a threshold for mor-

bidity at around 250 »g/m* as BS; hence mortality would

not be expected at lower levels. While the possibility of

surrogate behavior remains, the above arguments do not

demonstrate that smoke acts as a surrogate for non-

pollution variables. The trend toward higher coefficients

with lower pollution is not clearly consistent in the

Mazumdar and Ostro regressions. The existence of

higher coefficients in later years, however, prompted these

authors to suggest some plausible alternative to non-

pollution surrogates, including: (a) The possibility that

the composition of pollution changed with time, with an

ee a ae C

Cle

43a

increase in more toxic components, and (b) because the

gravimetric mass of particles in the range under 10 »m

may not have declined as much as did the black carbon

content detected in the smoke measurement (Lodge, 1986),

coefficients related only to smoke might be expected to in-

crease. An additional possibility suggested by Schwartz

and Marcus is that the effect of higher pollution epi-

sodes in earlier winters was blunted by public awareness

(and hence reduced exposure) or by a tendency for the

most susceptible individuals to succumb on an early day

of a multi-day pollution episode.

The use of the Lawther morbidity data as a threshold

for mortality is questionable. The London mortality data

involve an unequivocal endpoint in a relatively large pop-

ulation (several hundred per day) over a 14 year period.

As pointed out by Roth et al. (1986), although the bron-

chitic population studied was clearly susceptible, the ef-

fects indicator used by Lawther was a relatively insen-

sitive one. Moreover, the threshold was determined not

by rigorous analysis, but by visual examination of strip

chart data. Although the principal author strongly ob-

jects (Lawther, 1982), the criteria document points out

that the data do not clearly indicate an effects threshold

at 250 »g/m*. Furthermore, the simple correlation re-

sults provided by Lawther et al. (1970) suggest the pos-

sibility that a more sophisticated analysis jointly incor-

porating pollution and weather factors might have found

increased morbidity occurring at lower levels. The recent

findings of small changes in pulmonary function at lower

particulate matter levels in the U.S. and the Netherlands

(See Table 1) support the notion that 250 »g/m®* (in this

case as PM,,) is not a reliable effects threshold.

Comments: The derivation of the proposed range of

levels for the annual primary standard is without scien-

tific basis. In particular, limitations in the two major

series of studies used preclude finding effects of particu-

late matter at the lower TSP levels shown. In addition,

44a

the conversion of the results of these studies to PM,,

uses an inappropriately low PM,,/TSP ratio.

Agency Response: EPA’s assessment of studies used to

derive the range of levels for the primary standard

(Ferris et al., 1973, 1976; and Bouhuys et al., 1978)

(CD, pp. 14-44 to 46 and SP, pages 61-62 and 104-107)

was reviewed by CASAC and found to be an appropriate

basis for developing revised standard levels (Friedlander,

1982). The assessment clearly points out the limitations

and strengths associated with the uses of these studies.

The Ferris et al. work (See Table 2 above) involved

a “longitudinal” tracking of lung function and respira-

tory illness in adults vs. pollution over a 12 year period

in Berlin, NH, a small town in which a pulp mill was a

major pollution source. As commenters note, the “effects

likely” level drawn from the first year of this study is

particularly uncertain, as it is based on very limited

aerometry. This level, however, was not important in

developing the range for the proposed standard. Because

of the seriousness of the effect (a prolonged decrement in

lung function), the by then decreased concentration ob-

served in the first followup study (130 »g/m* as TSP),

was used in developing the upper bound of the range of

proposed annual standards. This concentration was based

on a full year of monitoring. Based on the historical rec-

ord, there can be little doubt that pollution declined in

this community from 1961 to 1967, the year of the first

follow-up. The nature of the particular pollution source

(a pulp mill) in this study, together with a finding of

very low British smoke level, indicates that a variety of

particles, not just products of combustion, may be asso-

ciated with adverse effects. Although commenters have

suggested that other pulp mill emissions may have been

responsible for the effects, ambient levels of the gaseous

effluents from such sources (reduced sulfur compounds

and SO.) have not been shown to cause reduced lung

function.

45a

Estimating PM,, levels from this study by using typi-

cal national average PM,,/TSP ratios does not—as some

commenters argue—clearly understate PM,, levels. These

commenters argued that high PM,,/TSP ratios (e.g., 0.8)

should be used because sites in the eastern US. tend to

have higher ratios. The data on PM,./TSP ratios, how-

ever, also show a general tendency for lower ratios to oc-

cur in industrialized areas with high TSP concentrations

(Pollack, et al., 1985). Moreover, air quality measure-

ments taken in the 1960’s document the presence of sub-

stantial quantities of larger size particles, as evidenced

by high dust fall levels and low soiling indexes (Kenline,

1962). The latter author concludes that this would be

expected “if the majority of particles present had diam-

eters of 10 microns or greater... .” EPA therefore

believes that the use of ratios characteristic of industrial-

ized areas with high particle concentrations is justified

and does not contribute to any excess margin of safety

in the estimated effects levels.

The Bouhuys et al. (1978) study (see Table 2 above)

was used to set the lower bound for the proposed stand-

ard range, which is the level at which the final standard

is being promulgated. The study found a difference in

three of five respiratory symptoms but no differences in

lung functions between two Connecticut towns (Ansonia

and Lebanon) that had a historically large (but currently

small) difference in levels of particulate matter. Al-

though the authors believed that air pollution did not play

a role in the observed differences in symptoms, the data

presented do not demonstrate that the differences were

due solely to other factors associated with the conduct

of the study. Moreover, the finding of excess respiratory

symptoms unaccompanied by a persistent change in lung

function is not unique. Similar firdings were also ob-

tained in the Ferris (1973) follow up study and the

more recent six city study results (Ware et al., 1986).

Some commenters argued that the estimated TSP levels

derived for the Bouhuys study were too low. EPA dis-

46a

agrees. The staff took the median TSP values reported

by Bouhuys et al. over the previous several years as the

relevant exposure level for this study because (1) the

current gradient in pollution appeared to be too small to

result in such effects, and (2) it is unreasonable to at-

tribute all of the observed gradient in effects among ur-

ban and rural residents, as measured in 1973, to the

maximum historical concentrations reported 8 to 10 years

prior to that time. EPA’s position is supported by the

observations of Ferris et al. (1973, 1976), which show

an apparent meaureable reduction in symptoms and im-

proved lung function after only a five to six year de-

cline in pollution. This decline suggests that any gradient

in effects due to pollution eight to ten years ago would be

diminished relative to effects that may be associated with

the more recent past. The median value used by EPA

for the Bouhuys study is, in fact, also relatively close

to the weighted average of all TSP observations reported

for Ansonia for the seven years preceding the Bouhuys

et al., (1978) measurements, which were taken in 1973

(Lounsbury, 1986).

The approach used to convert the TSP measurements

in this study to PM,, equivalents was also questioned.

The staff rejected use of the limited (15 days) particle

size data for Ansonia as unrepresentative because of

questions concerning their quality and because they were

taken in 1973, after particulate matter concentrations

had been reduced to lower levels (SP, p. 62). Absent

reliable site-specific particie size data, the staff used the

median PM,,/TSP ratio seen at other sites in the eastern

U.S. with higher than average PM,, levels. Because the

long-term ratio can vary between 02 and 0.65 among

such sites, such estimates are admittedly uncertain. Nev-

ertheless, the staff examination of historical air quality

and source data associated with the Bouhuys et al. study

found no factors that would make the ratio unusually

high or low relative to other high concentration sites in

the eastern U.S. The analysis by Spengler et al. (1986)

47a

of trends in particle size ratios from the 1970’s to the

present in six eastern cities suggests that the ratio of

PM,, to TSP in early years with higher TSP levels tends

to be comparable to or somewhat lower than the current

ratios.

The basis for the final ambient standard is consider-

ably strengthened by the recent results from the six-

cities study (Ware et al., 1986). This work also sug-

gests an increased risk of respiratory illness and symp-

toms, but no differences in lung function, in children

across a gradient of pollution that extends to concentra-

tions below those observed in the previous studies. The

results are therefore qualitatively consistent with both

of the earlier studies. In addition, the associated aero-

metry permits substantially better estimates of historical

PM,, data. Taken together, these studies provide sub-

stantial support for an annual standard of 50 pg/m’*.

3. Margin of Safety

Comments: The Agency has incorporated an unrecog-

nized three-fold margin of safety in the 24-hour stand-

ards through the means used to convert British Smoke

measurements into PM...

Agency Response: British Smoke measurements col-

lect particles smaller than about 4.5 microns in diameter

(PM,.;) on a substrate and then measure their absorp-

tion of light. Because the measurement depends on light

absorption, it is sensitive only to the dark, “sooty” com-

ponent of the particulate matter. EPA has relied on

gravimetric calibrations, performed during the earlier

years of the mortality and morbidity studies, that re-

lated the British Smoke measurements to particulate mass

concentrations that included light-colored as well as dark

particles.

The commenters note that the dark, sooty component

of the particulate matter in London today constitutes

48a

only 40% as large a fraction of the total particulate mass

as it did during the period of the studies on which EPA

has relied. They argue that the use of those studies to

set standards for contemporary particulate pollution

therefore introduces an error of a factor of 2.5 (1/0.4).

Multiplying this by a typical ratio of PM,, to PM,.,; of

1.2 (Lodge, 1986), the commenters arrive at an alleged

error of a factor of three arising from the Agency’s use

of the British Smoke measurements.

The commenters rely on the unstated assumption that

it is only the dark fraction of particulate pollution that

affects human health, and that, since the dark fraction

has declined since the time of the studies, the particulate

matter in the atmosphere today is less dangerous than

that present at the time of the studies. EPA disagrees

with this assumption and believes that a more plausible

and prudent assumption is that effects on health depend

on the mass concentration of particles and not on their

color.

Although it is possible that dark, carbonaceous particles

were primarily responsible for the observed effects on

human health in the London studies, this has not been

documented, and there is no evidence to support the as-

sumption that light-colored particles have no significant

effect on human health. EPA staff has compared the com-

position of particulate matter in historical London and in

the current U.S. and has concluded that, given the variety

of particle types present in the U.S., there is no clear

basis for imputing higher acute toxicity to the historical

London particles (SP pp. 21-22, 100).

The commenters support their argument with the as-

sertions that the decrease in the dark, sooty fraction of

particulate matter in London has been accompanied by

the elimination of pollution-related health effects, and

that current excursions of fine particle mass in excess of

250 »g/m* have not been associated with health effects in

London or elsewhere. EPA finds these assertions to be

ee Te rn ee ee ee}

hal

49a

unsupported. The studies of mortality in London over a

14-year period of declining pollution from 1958 through

1971 found that the relationship between pollution and .

mortality persisted throughout the period and that, in

fact, the regression coefficients assigned to mortality ap-

peared to increase over the period. (Mazumdar et al.,

1982; Ostro, 1984). Moreover, continuing studies in the

contemporary U.S. and Europe have suggested health

effects at PM, levels below 250 »g/m* (Dockery et al.,

1982; Ozkaynak and Spengler, 1985; Dassen et al.,

1986).

For these reasons, EPA concludes that it is reasonable

and prudent to use the mass concentration estimates de-

rived from historical British Smoke measurements to set

ambient standards for current U.S. atmospheres under

the assumption that current U.S. particles are equal in

toxicity to those found in London at the time of those

measurements. Any margin of safety inherent in the

British Smoke/PM,, conversion for the earlier years when

gravimetric calibrations were available is more likely to

be on the order of a factor of 1.2 (the ratio of PM.,.,

to PM,, estimated by Lodge, 1986) rather than the factor

of three suggested by the cormmenters. For particulate

levels lower than those observed in the earlier years,

EPA has supplemented the London studies with the more

contemporary American and European studies using di-

rect gravimetric measurements.

Comments: Several commenters expressed concerns

that the margin of safety for the range of levels proposed

for the 24-hour standard is insufficient. Commenters

based these concerns on: (a) Calculations suggesting that

even the lower bound may be less stringent than the cur-

rent standards, (b) evidence from the more recent studies

of lung function decrements in children and the analyses

of London mortality data, and (c) various studies found

to be mainly of qualitative value. In general, such com-

menters felt that, in view of the available evidence, the

50a

standard should be set at levels at or below the lower

bound of the proposed ranges.

Agency Response: The overriding consideration in se-

lecting a standard is how well it protects public health,

not its relative stringency as compared to the previous

standard. EPA believes that standards chosen provide an

adequate margin of safety irrespective of the relationship

to the former TSP standards. Nevertheless, EPA has

compared the stringency of the revised standards with

that of the existing standards by estimating the number

of areas that would be expected not to attain each set of

standards. By this measure, the new PM,, standards are

equivalent to or somewhat more stringent than the TSP

standards (SP, Table 2-1). Commenters who calculated

or asserted otherwise often did not take all of the aspects

of the standards into account. The margin of safety is

a function not only of level, but also of the indicator and

form of the standards. The revised form, in particular,

makes direct comparison of the relative stringency of

proposed range with the current TSP standard inappro-

priate.

EPA agrees that the analyses of mortality in London

justify caution in selecting a 24-hour standard level, and

that the recent studies of lung function provide a useful

basis for selecting the level. EPA does not, however, be-

lieve that these studies compel a standard more stringent

than the one chosen. As discussed in Section III.C.1

above, uncertainties in estimating PM,, equivalents of

low British Smoke concentrations in the later years of

the London studies make it difficult to use the studies to

set a precise level for a PM,, standard. Therefore, it is

important to examine the more contemporary studies of

lung function that permit a more direct estimation of

PM.,,, effects levels. In considering these studies in con-

junction with the London mortality and other relevant

health studies, EPA finds that a 24-hour standard of 150

;g/m* provides an adequate margin of safety. EPA does

nlc Pi

ee ee ee Vor

5la

not agree with commenters suggestions that it is neces-

sary to prevent any detectable changes in lung function.

As discussed in Section III.C.1, a standard of 150 pg/

m* will clearly prevent lung function decrements that

might be considered to be indicative of adverse effects in

well over 95% of children expused; in fact the evidence

suggests that even reversible lung function changes

(FEV.,..;) in excess of 10% are unlikely at this level.

EPA therefore believes that the standard provides an

adequate margin of safety.

Some commenters favoring standards below the lower

bounds of the proposed ranges relied on studies or analy-

ses found by EPA and CASAC to be of little quantitative

value for establishing ranges of concern. EPA considered

a number of such studies in selecting a margin of safety

(e.g., SPA 52-53; SP 109-111), but in EPA’s judgment

they do not provide a sufficient basis for establishing

standards at levels below those derived from the more

quantitative studies summarized in Tables 1 and 2 above.

Comments: Some commenters argued that in selecting

annual standards much greater weight be given to the

results of Ware et al. (1986), which suggest a possible

gradient of effects at concentrations extending to the

lowest levels observed in the six cities studies (25 »g/m*).

Agency Response: EPA disagrees. EPA staff found

that the pollution and effects gradient in the three clean-

est cities to be too small to provide any strong suggestion

of effects at such levels. Moreover, the lack of consistency

for “within city” effects in this study argue against plac-

ing undue reliance on the suggestion of effects at levels

outside of the range suggested by the other long-term

studies of interest (Ferris et al., 1973, 1976, Bouhuys

et al., 1978). In addition, the 24-hour standard provides

an increased margin of safety against annual exposures

at levels below 50 »g’m*, in areas where long-term ex-

posures are dominated by repeated short-term peaks

(Freas, 1986).

52a

List of Subjects in 40 CFR Part 50

Air pollution control, Carbon monoxide, Ozone, Sulfur

oxides, Particulate matter, Nitrogen dioxide, Lead.

Dated: June 2, 1987.

Lee M. Thomas,

Administrator.

PART 50—NATIONAL PRIMARY AND SECONDARY

AMBIENT AIR QUALITY STANDARDS

For reasons set forth in the preamble, Part 50 of

Chapter 1 of Title 40 of the Code of Federal Regulations

is amended as follows:

1. The authority citation for Part 50 continues to

read as follows:

Authority: Secs. 109 and 301(a), Clean Air Act, as

amended (42 U.S.C. 7409, 7601 (a) ).

2. Section 50.6 is revised to read as follows:

§ 50.6 National primary and secondary ambient air

quality standards for particulate matter.

(a) The level of the national primary and secondary

24-hour ambient air quality standards for particulate

matter is 150 micrograms per cubic meter (yg/m*), 24-

hour average concentration. The standards are attained

when the expected number of days per calendar year

with a 24-hour average concentration above 150 p»g/m’,

as determined in accordance with Appendix K to this

part, is equal to or less than one.

(b) The level of the national primary and secondary

annual standards for particulate matter is 50 micrograms

per cubic meter (»g/m*), annual arithmetic mean. The

53a

standards are attained when the expected annual arith-

metic mean concentration, as determined in accordance

with Appendix K to this part, is less than or equal to 50

g/m’,

primary and secondary standards, particulate matter

shall be measured in the ambient air as PM,, (particles

with an aerodynamic diameter less than or equal to a

nominal 10 micrometers) by:

(1) A reference method based on Appendix J and des-

ignated in accordance with Part 53 of this chapter, or

(2) An equivalent method designated in accordance

with Part 53 of this chapter.

54a

APPENDIX B

STATUTORY PROVISIONS

CLEAN AIR ACT

42 U.S.C. §§ 7401, et seq. (1982)

(Excerpts)

1. Section 108, 42 U.S.C. § 7408 (1982)

§ 7408. Air quality criteria and control techniques

(a) Air pollutant list; publication and revision by Ad-

ministrator; issuance of air quality criteria for air pol-

lutants. (1) -For the purpose of establishing national

primary and secondary ambient air quality standards,

the Administrator shall within 30 days after the date of

enactment of the Clean Air Amendments of 1970 [en-

acted Dec. 31, 1970] publish, and shall from time to time

thereafter revise, a list which includes each air pollu-

tant—

(A) emissions of which, in his judgment, cause or

contribute to air pollution which may reasonably be

anticipated to endanger public health or welfare;

(B) the presence of which in the ambient air re-

sults from numerous or diverse mobile or stationary

sources; and

sued before the date of enactment of the Clean Air

Amendments of 1970 [enacted Dec. 31, 1970], but

for which he plans to issue air quality criteria under

this section.

(2) The Administrator shall issue air quality criteria for

an air pollutant within 12 months after he has included

such pollutant in a list under paragraph (1). Air quality

criteria for an air pollitant shall accurately reflect the

latest scientific knowledge useful in indicating the kind

and extent of all identifiable effects on public health or

55a

welfare which may be expected from the presence of such

pollutant in the ambient air, in varying quantities. The

criteria for an air pollutant, to the extent practicable,

shall include information on—

(A) those variable factors (including atmospheric

conditions) which of themselves or in combination

with ether factors may alter the effects on public

health or welfare of such air pollutant;

(B) the types of air pollutants which, when present

in the atmosphere, may interact with such pollutant

to produce an adverse effect on public health or wel-

fare; and

welfare.

2. Section 109, 42 U.S.C. § 7409 (1982)

§ 7409. National primary and secondary ambient air

quality standards

(a) Promulgation

(1) The Administrator—

(A) within 30 days after December 31, 1970,

shall publish proposed regulations prescribing a na-

tional primary ambient air quality standard and a

national secondary ambient air quality standard for

each air pollutant for which air quality criteria have

been issued prior to such date; and

(B) after a reasonable time for interested persons

to submit written comments thereon (but no later

than 90 days after the initial publication of such

proposed standards) shall by regulation promulgate

such proposed national primary and secondary am-

bient air quality standards with such modifications

as he deems appropriate.

56a

(2) With respect to any air pollutant for which air

quality criteria are issued after December 31, 1970, the

Administrator shall publish, simultaneously with the is-

suance of such criteria and information, proposed national

primary and secondary ambient air quality standards for

any such pollutant. The procedure provided for in para-

graph (1)(B) of this subsection shall apply to the prom-

ulgation of such standards.

(b) Protection of public health and welfare

(1) National primary ambient air quality standards,

prescribed under subsection (a) of this section shall be

ambient air quality standards the attainment and mainte-

nance of which in the judgment of the Administrator,

based on such criteria and allowing an adequate margin

of safety, are requisite to protect the public health. Such

primary standards may be revised in the same manner as

promulgated.

(2) Any national secondary ambient air quality stand-

ard prescribed under subsection (a) of this section shall

specify a level of air quality the attainment and mainte-

nance of which in the judgment of the Administrator,

based on such criteria, is requisite to protect the public

welfare from any known or anticipated adverse effects

associated with the presence of such air pollutant in the

ambient air. Such secondary standards may be revised

in the same manner as promulgated.

. * * *

(d) Review and revision of criteria and standards; in-

dependent scientific review committee; appointment;

advisory functions

(1) Not later than December 31, 1980, and at five-year

intervals thereafter, the Administrator shall complete a

thorough review of the criteria published under section

7408 of this title and the national ambient air quality

standards promulgated under this section and shall make

57a

such revisions in such criteria and standards and promul-

gate such new standards as may be appropriate in ac-

cordance with section 7408 of this title and subsection

(b) of this section. The Administrator may review and

revise criteria or promulgate new standards earlier or

more frequently than required under this paragraph.

(2)(A) The Administrator shall appoint an independ-

ent scientific review committee composed of seven mem-

bers including at least one member of the National Acad-

emy of Sciences, one physician, and one person represent-

ing State air pollution control agencies.

(B) Not later than January 1, 1980, and at five-year

intervals thereafter, the committee referred to in sub-

paragraph (A) shall complete a review of the criteria

published under section 7408-ef+his title and the national

primary and secondary ambient air quality standards

promulgated under this section and shall recommend to

the Administrator any new national ambient air quality

standards and revisions of existing criteria and standards

as may be appropriate under section 7408 of this title

and subsection (b) of this section.

ministrator of areas in which additional knowledge is

required to appraise the adequacy and basis of existing,

new, or revised national ambient air quality standards,

(ii) describe the research efforts necessary to provide the

required information, (iii) advise the Administrator on

the relative contribution to air pollution concentrations

of natural as well as anthropogenic activity, and (iv)

advise the Administrator of any adverse public health,

welfare, social, economic, or energy effects which may

result from various strategies for attainment and main-

tenance of such national ambient air quality standards.

* * . *

58a

3. Section 112, 42 U.S.C. § 7412 (1982).

§ 7412. National emission standards for hazardous air

pollutants

(a) Definitions. For purposes of this section—

(1) The term “hazardous air pollutant” means an

air pollutant to which no ambient air quality stand-

ard is applicable and which in the judgment of the

Administrator causes, or contributes to, air pollution

which may reasonably be anticipated to result in an

increase in mortality or an increase in serious ir-

reversible, or incapacitating reversible, illness.

(2) The term “new source” means a stationary

source the construction or modification of which is

commenced after the Administrator proposes regula-

tions under this section establishing an emission

standard which will be applicable to such source.

(3) The terms “stationary source’, “modification”,

“owner or operator” and “existing source” shall have

the same meaning as such terms have under section

111(a) [42 USCS § 7411(a)].

(b) List of hazardous air pollutants; emission standards;

pollution control techniques. (1)(A) The Administrator

shall, within 90 days after the date of enactment of the

Clean Air Amendments of 1970 [enacted Dec. 31, 1970],

publish (and shall from time to time thereafter revise)

a list which includes each hazardous air pollutant for

which he intends to establish an emission standard under

this section.

(B) Within 180 days after the inclusion of any air pol-

lutant in such list, the Administrator shall publish pro-

posed regulations establishing emission standards for

such pollutant together with a notice of a public hearing

within thirty days. Not later than 180 days after such

publication, the Administrator shall prescribe an emis-

sion standard for such pollutant, unless he finds, on the

basis of information presented at such hearings, that

59a

such pollutant clearly is not a hazardous air pollutant.

The Administrator shall establish any such standard at

the level which in his judgment provides an ample margin

of safety to protect the public health from such hazardous

air pollutant.

section shall become effective upon promulgation.

(2) The Administrator shall, from time to time, issue

information on pollution control techniques for air pol-

lutants subject to the provisions of this section.

date of any emission standard under this section—

(A) no person may construct any new source or

modify any existing source which, in the Administra-

tor’s judgment, will emit an air pollutant to which

such standard applies unless the Administrator finds

that such source if properly operated will not cause

emissions in violation of such standard, and

(B) no air pollutant to which such standard applies

may be emitted from any stationary source in viola-

tion of such standard, except that in the case of an

existing source—

(i) such standard shall not apply until 90 days

after its effective date, and

(ii) the Administrator may grant a waiver per-

mitting such source a period of up to two years

after the effective date of a standard to comply

with the standard, if he finds tliat such period

is necessary for the installation of controls and

that steps will be taken during the Period of the

waiver to assure that the health of persons will

be protected from imminent endangerment.

(2) The President may exempt any stationary source

from compliance with paragraph (1) for a period of not

60a

more than two years if he finds that the technology to

implement such standards is not available and the opera-

tion of such source is required for reasons of national

security. An exemption under this paragraph may be

extended for one or more additional periods, each period

not to exceed two years. The President shall make a re-

port to Congress with respect to each exemption (or

extension thereof) made under this paragraph.

* * * *

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.