(121a) Searching for Answers

The Southeastern Aerosol Research and Characterization Study (SEARCH) was implemented in 1998-1999 in an effort to provide extensive long-term data on the sources and chemical characteristics of atmospheric particulate matter (PM), particularly for the southeastern U. S. with its distinctive meteorological and demographical characteristics. The SEARCH study's objectives include: (i) development of a long-term chemical climatology of PM; (ii) advancement of the understanding of PM composition, variability and sources; (iii) establishment of a platform for the development and testing of new measurement methods related to PM; and, (iv) collaboration with states, federal agencies and others in carrying out special studies at selected network sites. SEARCH is unique in the breadth, high time resolution and longevity of trace atmospheric measurements that have been made at eight sites across the southeastern U. S. At four pairs of urban/rural or urban/suburban monitoring sites located in Atlanta, GA, Birmingham, AL, Gulfport, MS, and Pensacola, FL, meteorological (temperature, pressure, wind speed and direction, humidity, solar insolation) , trace gas (O₃, SO₂, CO, NO, NO₂, NO_y, HNO₃, NH₃), fine PM (PM_2.5 mass and composition), and coarse PM data (PM_10-2.5 mass and composition) have been routinely collected since the network's inception. The SEARCH dataset provides a rich repository for the investigation of many scientific questions concerning the sources, formation and behavior of atmospheric PM. This paper will present an overview of selected results from investigations that have been undertaken to date with SEARCH data.