Colleen McKaughan, EPA Region 9 December 14, 2005 Update on Upcoming Proposed Revisions to the PM2.5 and PM10-2.5 Standards Colleen McKaughan, EPA Region 9 December 14, 2005

Overview History and schedule for PM standards PM2.5 -- current std. and EPA recommendations PM10 -- current std. and EPA recommendations for a new PM coarse std. Stakeholder comments Status of Region 9 areas under the PM10 standards Next Steps

History The Clean Air Act requires periodic reviews and updates of air quality standards A 1997 Court decision found PM10 to be a poorly matched indicator for PM10-2.5 particles because it includes PM2.5 OAQPS has prepared a Staff Paper with recommendations for new PM fine and PM coarse standards to EPA’s Administrator

Schedule for the new standards July 2005 - EPA’s Staff Paper was finalized Sept 15, 2005 - Clean Air Scientific Advisory Committee (CASAC) provided a final letter to EPA with recommendations The above two documents are available at www.epa.gov/ttn/naaqs/standards/pm/s_pm_ index.html Dec. 20, 2005 - consent decree deadline for proposed rule Sept. 27, 2006 - consent decree deadline for final rule

Current PM2.5 Standards 24-hour standard of 65 ug/m3 Annual standard of 15 ug/m3

EPA Staff Paper Recommendations for PM2.5 Standard New scientific evidence warrants a more protective standard Strengthen the 24-hour std. to 25 - 30 ug/m3 and retain the annual std. OR 30 - 40 ug/m3 and strengthen annual std. to 12 - 14 ug/m3

Current PM10 Standard In the West, PM10 emissions are dominated by PM10-2.5 particles 24-hour standard of 150 ug/m3 Annual standard of 50 ug/m3 Applies universally to all PM-10 and smaller-size particles All monitored exceedences factor into the standard except those flagged and concurred as natural or exceptional events under EPA’s Natural Events Policy

Summary of EPA Staff Paper Recommendations for PM10-2.5 Scientific evidence less certain than for PM2.5 An urban (UPM10-2.5) 24-hour standard No annual standard UPM10-2.5 monitors to be located in areas with populations of 100,000 or more Densely populated communities w/ 500 people/sq. mile are preferred for UPM10-2.5 monitoring locations

Summary of Staff Paper Recommendations for PM10-2.5 98th percentile standard ranging from 50-70 ug/m3 OR 99th percentile standard ranging from 60-85 ug/m3

Summary of Staff Paper Recommendations for PM10-2.5 Urban emphasis based on the following: Toxicity is responsible for adverse health effects from coarse particles rather than size alone PM coarse particles associated with heavily trafficked paved roads and industrial point sources are enriched by toxic contaminants Higher exposures to coarse particles enriched by toxic contaminants generally occur in urban areas

Stakeholder Input EPA held a public teleconference call with CASAC on August 11, 2005 Several Region 9 States & Districts have provided adverse comments to EPA regarding exclusion of rural areas CARB, ADEQ, NDEP Great Basin APCD, Clark County DAQEM, Pinal County AQCD, Washoe County AQMD

Areas in CA, NV, and AZ Violating the PM10 Standards (based on ’02-’04 data) 19 areas violating, excluding areas with exceedences likely caused by natural or exceptional events With respect to the recommended UPM10-2.5 standard: 6 areas have population < 100,000 Another 5 areas have exceedences that would not be captured under a 98th percentile form of the PM coarse standard Some of the remaining areas have one or more rural-setting monitors violating the standard

Next Steps EPA’s proposed rule is due December 20 www.epa.gov/ttn/naaqs/standards/pm/s_pm_ index.html WRAP agencies will have an opportunity to provide written comments during the public comment period We encourage collection of speciation data at both urban and rural PM monitors and research on rural dust toxicity