AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
United States National PM2.5 Chemical Speciation Monitoring Networks – CSN and IMPROVE: Description of Networks
PAUL A. SOLOMON, Jeff J. Lantz, Dennis Crumpler, James B. Flanagan, R.K.M. Jayanty, Edward E. Rickman, Charles McDade, Lowell Ashbaugh, U.S. EPA, Office of Reserach and Development, Las Vegas, NV
Abstract Number: 23 Working Group: Urban Aerosols
Abstract EPA initiated the national PM2.5 Chemical Speciation Monitoring Network (CSN) in 2000 to support evaluation of long-term trends and to better quantify source impacts of particulate matter (PM) in the size range below 2.5 micro-meter aerodynamic diameter (PM2.5). The network peaked at about 200 sites in 2005. In response to the 1999 Regional Haze Rule and the need to better understand the regional transport of PM, EPA also augmented the long existing Interagency Monitoring of Protected Visual Environments (IMPROVE) visibility monitoring network in 2000, adding nearly 100 additional IMPROVE sites in rural Class 1 Areas across the country. The IMPROVE network peaked to about 170 sites in 2004. Both networks measure the major chemical components of PM2.5 using historically accepted filter-based methods. Components measured by both networks include major anions, carbonaceous material, and a series of trace elements. CSN also measures ammonium and other cations directly whereas IMPROVE estimates ammonium assuming complete neutralization of the measured sulfate and nitrate. IMPROVE also measures chloride and nitrite. In general, the field and laboratory approaches used in the two networks are similar; however, there are numerous, often subtle differences in sampling and chemical analysis methods, shipping, field quality control practices, and data handling and flagging. These could potentially impact merging the two datasets when used to better understand source impacts and the regional nature and long-range transport of PM2.5. This presentation describes these networks as they existed in 2001 to 2006, outlines differences in field and laboratory approaches, provides a summary of the analytical parameters that address data uncertainty, and summarizes major network changes since 2006.