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COMPARISON OF DATA FROM THE STN AND IMPROVE NETWORKS
Citation:
MCDADE, C. E., W. H. WHITE, N. P. HYSLOP, P. A. SOLOMON, T. KLAMSER-WILLIAMS, D. CRUMPLER, AND P. P. EGEGHY. COMPARISON OF DATA FROM THE STN AND IMPROVE NETWORKS. Presented at American Association of Aerosol Research 2005, Atlanta, GA, February 07 - 11, 2005.
Impact/Purpose:
Develop and evaluate methods for the sampling and analysis of PM in ambient air, with emphasis on FRM/FEM for PMc, measurement of carbonaceous aerosols, measurement of biogenic aerosols, comparisons measurements from the STN and IMPROVE monitoring networks, and continuous methods for PM mass and its chemical components.
Description:
Two national chemical speciation-monitoring networks operate currently within the United States. The Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network operates primarily in rural areas collecting aerosol and optical data to better understand the causes of regional haze in Class I areas. IMPROVE began operation in 1988. The Speciation Trends Network (STN) operates in urban locations collecting aerosol data to better understand the causes of PM2.5 levels that exceed the National Ambient Air Quality Standards for Particulate Matter (PM) established in 1997. STN began operation in late 2000.
EPA desires to integrate data from both networks to allow for a regional approach to reducing PM in urban areas since concentrations of PM in urban areas are strongly influenced by regional levels. While both networks are based on 24-hour filter sampling, there are differences in the sampling and chemical analysis methods employed. These differences range from the inlet of the samplers to how data are processed before final concentrations are reported.
EPA, in conjunction with UC Davis and others, has conducted collocated sampling since October 2001 at three sets of paired urban-rural sites (Washington, DC; Phoenix, AZ; and Seattle, WA). Collocated STN and IMPROVE samplers were operated at all sites and analyzed for major components (sulfate, nitrate, organic carbon, and elemental carbon) and trace elements (e.g., Fe, Ca, Si). Each network followed its own specific protocols.
Comparison results from the first year of sampling (October 2001-September 2002) have been reported previously. This paper expands those analyses by incorporating the second year (October 2002-September 2003). Furthermore, IMPROVE initiated its own in-network collocated sampling program during 2003 to assess the precision of IMPROVE data. Those precision data are utilized to provide a baseline for comparing aerosol data from the two different networks. The approach for doing so is described in a companion paper at this conference (White, et al., 2005).
Reference: Warren H. White, Nicole P. Hyslop, and Charles E. McDade, "Using In-Network Precision Data as a Basis for Cross-Network Comparisons" (2005).
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.