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The U.S. Environmental Protection Agency (EPA) initiated the national PM2.5Chemical Speciation Monitoring Network (CSN) in 2000 to support evaluation of long-term trends and to better quantify the impact of sources on particulate matter (PM) concentrations in the size range below 2.5 μm aerodynamic diameter (PM2.5; fine particles). The network peaked at more than 260 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. Both networks measure the major chemical components of PM2.5using 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, and quality control practices. These could potentially affect merging the two data sets when used to understand better the impact of sources on PM concentrations and the regional nature and long-range transport of PM2.5. This paper describes, for the first time in the peer-reviewed literature, these networks as they have existed since 2000, outlines differences in field and laboratory approaches, provides a summary of the analytical parameters that address data uncertainty, and summarizes major network changes since the inception of CSN.ImplicationsTwo long-term chemical speciation particle monitoring networks have operated simultaneously in the United States since 2001, when the EPA began regular operations of its PM2.5 Chemical Speciation Monitoring Network (IMPROVE began in 1988). These networks use similar field sampling and analytical methods, but there are numerous, often subtle differences in equipment and methodologies that can affect the results. This paper describes these networks since 2000 (inception of CSN) and their differences, and summarizes the analytical parameters that address data uncertainty, providing researchers and policymakers with background information they may need (e.g., for 2018 PM2.5 designation and State Implementation Plan process; McCarthy, 2013) to assess results from each network and decide how these data sets can be mutually employed for enhanced analyses. Changes in CSN and IMPROVE that have occurred over the years also are described. [ABSTRACT FROM AUTHOR]

The article considers the Particulate Matter Supersites Program air quality monitoring program of the U.S. Environmental Protection Agency (EPA). Results obtained from the Supersites Program and their application to air quality policy development by the EPA, state and local government agencies and private business enterprises are discussed.

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. [ABSTRACT FROM AUTHOR]

The article introduces the January 2, 2004 issue of the journal Aerosol Science and Technology. In July 1997, the U.S. Environmental Protection Agency (EPA) issued new National Ambient Air Quality Standards for fine particulate matter (PM). EPA recognized that an improved understanding of the key sources, development of the most cost effective control strategies, and health risks associated with PM would depend on the availability of high quality measurements of PM composition, and concentration over a variety of spatial and temporal scales. This special issue of reports on results from various air quality measurement projects and spans the full range of objectives for these projects.

An introduction is presented in which the editor discusses various reports within the issue on topics featured during the 2010 American Association for Aerosol Research (AAAR) Air Pollution and Health Conference including importance of multipollutant approach, air pollution components, and population characteristics review related to susceptibility.

The article explores organic carbon artifacts correction methods for quartz-fiber filters in large routine sampling network. When using the regression method (RM), it was found that a linear relationship was seen between organic carbon (OC) and particulate matter (PM) but according to the authors, this is not always the case. The authors recommend that backup filter sampling on at least 10% of sampling days is the most relatively accurate and cost-effective method in OC estimation.