Key Scientific Findings and Policy- and Health-Relevant Insights from the U.S. Environmental Protection Agency’s Particulate Matter Supersites Program and Related Studies: An Integration and Synthesis of Results

Abstract

In 1998, the U.S. Environmental Protection Agency (EPA) initiated a major air quality program known as the Particulate Matter (PM) Supersites Program. The Supersites Program was a multiyear, $27 million air quality monitoring program consisting of eight regional air quality projects located throughout the United States, each with differing atmospheric pollution conditions resulting from variations in source emissions and meteorology. The overall goal of the program was to elucidate source-receptor relationships and atmospheric processes leading to PM accumulation on urban and regional scales; thus providing the scientific underpinning for modeling and data analysis efforts to support State Implementation Plans and more effective risk management approaches for PM. The program had three main objectives: (1) conduct methods development and evaluation, (2) characterize ambient PM, and (3) support health effects and exposure research. This paper provides a synthesis of key scientific findings from the Supersites Program and related studies. EPA developed 16 science/policy-relevant questions in conjunction with state and other federal agencies, Regional Planning Organizations, and the private sector. These questions were addressed to the extent possible, even given the vast amount of new information available from the Supersites Program, in a series of papers published as a special issue of the Journal of Air & Waste Management Association (February 2008).This synthesis also includes discussions of: (1) initial Supersites Program support for air quality management efforts in specific locations throughout the United States;(2) selected policy-relevant insights, based on atmospheric sciences findings, useful to air quality managers and decision makers planning emissions management strategies to address current and future PM National Ambient Air Quality Standards (NAAQS) and network planning and implementation; (3) selected health-relevant insights interpreted from atmospheric sciences findings in light of future directions for health and exposure scientists planning studies of the effects of PM on human health; and (4) selected knowledge gaps to guide future research. Finally, given the scope and depth of research and findings from the Supersites Program, this paper provides a reference source so readers can glean a general understanding of the overall research conducted and its policy-relevant insights. Supporting details for the results presented are available through the cited references. An annotated table of contents allows readers to easily find specific subject matter within the text. IMPLICATIONSOver 400 peer-reviewed journal articles and likely more than 1000 presentations resulted from the research conducted through EPA's PM Supersites Program. From the start, the program was developed with a policy focusproviding new information on the accumulation and sources of PM in air on urban and regional scales that might allow for the development of more effective approaches to reducing ambient concentrations of PM to...

Personal exposure to ultrafine particles

“…Outdoor UFP concentrations were measured for 1-2 years in several US cities (U.S. EPA Supersites program; Solomon et al, 2008), and near roadways in California (Zhu et al, 2002) and also in Erfurt and Augsberg, Germany (Wichmann et al, 2000). Residential indoor concentrations have also been reported (Abt et al, 2000;Dennekamp et al, 2001;Long et al, 2001;Wallace and Howard-Reed, 2002;Klepeis et al, 2003;He et al, 2004;Wallace, 2000Wallace, , 2005Wallace, , 2006Wallace et al, 2004Wallace et al, , 2008Hoek et al, 2008).…”

The National Ambient Air Monitoring Strategy: Rethinking the Role of National Networks

“…Continuous data add insight to health assessments, addressing subdaily averaging times, source apportionment studies relating impacts to direct emission sources, atmospheric processing and transformation, and air quality models predicated on capturing diurnal air quality patterns of pollutant behavior. 14,16,18,19 Diversity of "Representative" Locations. A variety of sites representing urban (large and medium size cities) and rural (characterizing background and transport corridors) areas support multiple objectives.…”

“…Continued efforts are needed for development of similar methods in the ultrafine and PM 10 -2.5 size ranges because recent studies are also finding adverse health effects associated with particles in these size ranges. 19 Use of modeling results to add spatial and temporal richness in sparsely monitored areas requires continued development and evaluation to better understand the value and caveats of these approaches for application to human and environmental welfare risk assessments and delineation of nonattainment areas. These recommendations reflect a community wide consensus formed around 2003, yet remain consistent with recommendations generated by the 2004 NAS report, "Air Quality Management in the United States."…”

“…16,17 Just as emission sources are characterized by a multiplicity of pollutant releases, related source apportionment models yield more conclusive results from use of multiple measurements. 18,19 Multiple measurements streamline monitoring operations and offer increased diagnostic capabilities to improve instrument performance. 14,20 -22 In addition, as we move aggressively to integrate continuous PM (e.g., both mass and speciation) monitors into the network, it is important to retain several collocated integrated filter-based and continuous instruments because the relationships between these methods are not fully understood 20 and now also are subject to future changes brought on by modifications of aerosol composition and improvement in methods.…”

PM2.5 Emissions from Aluminum Smelters: Coefficients and Environmental Impact

“…First, Gaussian distribution and variance homogeneity were confirmed by graphical examination of the residuals. 24 The systematic and random errors (bias and precision) of the two methods were considered as the same constant because every weighing was conducted on the same kind of analytical balance. This error constant does not then impact further comparisons of the two methods.…”