PM 10-2.5 Methods Update and Network Design

1. PM10-2.5 Methods Update and Network Design Presentation for WESTAR San Diego, CA September 2005 Peter Tsirigotis Director Emissions, Monitoring, and Analysis Division; U.S. EPA Office of Air Quality, Planning and Standards

2. PM10-2.5 Methods Update • Multi-city field study of commercially available PM10-2.5 technologies completed and reviewed by CASAC Technical Subcommittee in 2004 • Included continuous methods for hourly data and filter-based methods to obtain integrated daily samples • Additional field study in Phoenix completed spring 2005 • Several technologies modified to improve performance prior to this study • New field study being deployed in Birmingham, AL • Upcoming meeting of the CASAC scheduled for September 21-22, 2005 to provide: • Peer review on a PM10-2.5 Federal Reference Method (FRM) • Consultations on the evaluation of PM10-2.5 field studies, optimization of the PM2.5 FRM, equivalency criteria for PM2.5 and PM10-2.5, and data quality objectives for PM10-2.5. • Materials available at: http://www.epa.gov/ttn/amtic/files/ambient/pm25/casac/casacmemo.pdf

3. PM10-2.5 Methods Update Take Home Messages: • Filter-based difference method (separate low-volume FRMs for PM10 and PM2.5) has better data quality compared to other commercially available methods • Not expected to be widely deployed, but will serve as basis of comparison for approving continuous methods • Continuous method evaluations have demonstrated high sample completeness, and good precision and correlation between methods • Biases do exist between methods; however, new studies may address this • Samplers potentially usable for speciation • Coarse channel of filter-based dichotomous sampler • Analysis of PM10 filter and subtraction of Speciation Trends Network PM2.5 data • Customized samplers specially designed for this purpose • Data Quality Objectives demonstrate the value of continuous methods to reduce uncertainty in support of a potential daily PM10-2.5 standard

4. PM10-2.5 Network Design • Available epidemiological evidence is being considered in designing the coarse particle monitoring network. • Greatest health concern in urban areas where particles become enriched with contaminants from road dust and industrial sources • Less concern for exposure to natural materials of geologic origin • Lack of evidence limits conclusions on toxicity of agricultural and mining sources • CASAC concluded that available evidence from health studies suggests focus on urban, not rural coarse particles. • More narrowly defined indicator (UPM10-2.5) proposed to characterize risk from urban sources such as re-suspended road dust typical of high traffic-density areas and emissions from industrial sources

5. PM10-2.5 Network Design • Proposed design similar in concept to PM2.5 monitoring for the daily standard • Focus on areas of high population density and proximity to primary industrial sources of urban particles • Rural monitoring as part of NCore Level 2 multi-pollutant sites • Speciation requirements under consideration • Minimum EPA monitoring requirements based on criteria including population size and estimated UPM10-2.5 concentrations • Draft changes to 40 CFR 58, Appendix D and E must be signed for NPRM by December 20, 2005