Peer Review of CASTNet

ENVIRONMENTAL PROTECTION AGENCY

[FRL-5695-3]

Peer Review of CASTNet

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of meeting.

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SUMMARY: The United States Environmental Protection Agency announces

the meeting of a peer review panel which is constituted to review and

analyze the EPA draft report, Examination of CASTNet: Data, Results,

Costs, and Implications and the accompanying Recommendations on Changes

to Operational Monitoring in CASTNet and Directions for Future

Atmospheric Deposition Monitoring Research. The meeting will be held on

Wednesday, March 26, 1997, at the Holiday Inn Arlington at Ballston,

4610 N. Fairfax Drive, Arlington, VA 22203. The meeting will begin at 9

a.m. and adjourn by 5 p.m. The meeting is open to the public. Any

member of the public who would like to comment on the draft report

should contact Dr. Robert E. Menzer, Office of Research and Development

(8701), USEPA, 401 M Street, SW, Washington, DC 20460, telephone 202-

260-5779, Email: [email protected], for a copy of the

report. Written comments should be submitted to Dr. Menzer. Members of

the public who choose to make brief comments on the report at the

meeting should also contact Dr. Menzer.

SUPPLEMENTARY INFORMATION: In 1986, EPA's Office of Research and

Development began to operate the National Dry Deposition Network,

consisting of 39 monitoring sites designed to assess the status and

trends in dry deposition of sulfur and nitrogen species, primarily in

the high-deposition regions in the eastern U.S. Following passage of

the Clean Air Act Amendments (CAAA) of 1990, the NDDN was expanded and

renamed the Clean Air Status and Trends Network (CASTNet). As of 1996,

there are 51 operational sites in the network. Each site collects

weekly filter pack samples which are analyzed for SOX, NOX,

and sulfate, nitrate, and ammonium ions, as well as micrometeorological

and other data.

The first systematic analyses of the resulting monitoring data were

conducted beginning in the fall of 1996 by scientists at ORD's National

Exposure Research Laboratory. This timing allowed the first access to

quality-assured data from 1995, during which SOX emissions

decreased by 13% in response to Phase I reductions in sulfur emissions

called for in the CAAA. The purpose of the analyses was to examine the

performance of the monitors and to seek opportunities to increase the

cost-effectiveness of the network. The analyses included reviews of the

quality of the database and the costs of the individual data collection

components; comparisons between deposition velocities derived from the

multi-layer model using meteorological data collected on site with

deposition velocities measured using an eddy correlation technique;

evaluation of alternative methods of calculating deposition velocities

that do not require on-site data collection; analysis of factors

affecting variability in deposition velocity at two different spatial

scales; exploration of the effect of reducing the number of sites on

apparent regional patterns of ambient sulfur dioxide concentrations;

evaluation of the ability to detect trends in ambient concentrations

and deposition velocities at individual sites and groups of

geographically contiguous sites; and comparisons of dry deposition

estimates with wet deposition estimates from nearby wet deposition

sites. The results of the analyses are presented in a draft report,

Examination of CASTNet: Data, Results, Costs, and Implications. The

purpose of this review is to examine the soundness of the underlying

science and the appropriateness of the analytical approaches described

in this document.

Beginning in FY 1998, EPA is proposing to transfer operation of

CASTNet from the Office of Research and Development (ORD) to the Office

of Air and Radiation (OAR). The transition from a research-oriented

effort to an operational monitoring program presents an opportunity to

make changes in current network operations and to assess alternative

directions for future acid deposition research. The Recommendations on

Changes to Operational Monitoring in CASTNet and Directions for Future

Atmospheric Deposition Monitoring Research makes such recommendations

to OAR and ORD, based on policy questions provided by OAR and informed

by the analyses in the accompanying draft report. The other purpose of

the peer review is to solicit the reviewers'' advice on the

reasonableness of the various proposed modifications to the CASTNet and

future research directions, given the current state of data analysis

and interpretation.

Dated: February 19, 1997.

Joseph K. Alexander,

Acting Assistant Administrator for Research and Development.

[FR Doc. 97-4967 Filed 2-27-97; 8:45 am]

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