PM 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

PM Methods Update Multi-city field study of commercially available PM 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 PM Federal Reference Method (FRM) –Consultations on the evaluation of PM field studies, optimization of the PM 2.5 FRM, equivalency criteria for PM 2.5 and PM , and data quality objectives for PM –Materials available at:

PM Methods Update Take Home Messages: Filter-based difference method (separate low-volume FRMs for PM 10 and PM 2.5 ) 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 PM 10 filter and subtraction of Speciation Trends Network PM 2.5 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 PM standard

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 (UPM ) proposed to characterize risk from urban sources such as re- suspended road dust typical of high traffic-density areas and emissions from industrial sources PM Network Design

Proposed design similar in concept to PM 2.5 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 UPM concentrations Draft changes to 40 CFR 58, Appendix D and E must be signed for NPRM by December 20, 2005 PM Network Design