Measurement of PM(2.5), including semi-volatile components, in the EPA EMPACT and STAR programs: Results from the Salt Lake City, Bountiful and Lindon, Utah studies and implications for public awareness, health effects, and control strategies

The Salt Lake City EPA Environmental Monitoring for Public Access and Community Tracking (EMPACT) project, initiated in October 1999, and the BYU-EPA Science to Achieve Results (STAR) project, initiated in November 2000 were designed to evaluate the usefulness of a newly developed real-time continuous monitor (RAMS) for total (non-volatile plus semi-volatile) PM_2.5 mass and the health relevance of PM_2.5 measured by this method as compared to other measurements of PM_2.5 parameters. Ammonium nitrate and semi-volatile organic material (SVOM) are significant components of fine particles in many urban atmospheres. These components however, are not properly measured by current EPA accepted methods, such as the PM _2.5 FRM and R&P TEOM monitor, due to loss of semi-volatile material (SVM) from particles during sampling. The accurate determination of semi-volatile material is critical due to the possible effects of these species on human health, visibility and global climate change.; The concentration and composition of fine particulate material has been measured using a combination of continuous and integrated samplers at the Brigham Young University-EPA Environmental Monitoring for Public Access and Community Tracking (BYU-EPA EMPACT) monitoring site in Salt Lake City, Utah and the EPA Science To Achieve Results (STAR) monitoring sites in Bountiful and Lindon, Utah, over a two-year period (November 1999–February 2002). Results obtained for the continuous determination of total PM_2.5 mass with the RAMS have been validated by comparison with results obtained from collocated PC-BOSS diffusion denuder integrated samples. These results indicate that the RAMS can be used to accurately and continuously measure PM_2.5 mass, including semi-volatile material.; The accurate determination of PM_2.5 mass, including semi-volatile material, on a continuous basis using the RAMS as well as short- and long-term integrated determination of PM_2.5 mass and chemical composition with the PC-BOSS, when combined with other monitoring methods used in the Salt Lake City EPA EMPACT and the EPA STAR projects, provided previously unavailable information on the composition, concentration, sources and light scattering of fine particulate matter suspended in the atmosphere. This information, by providing a more complete description of the exposure component for health studies, should provide a better understanding of health relevant parameters associated with exposure to fine particles.