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

2. Overview History and schedule for PM standards
PM 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

3. 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 PM 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

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

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

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

7. Current PM10 Standard
In the West, PM10 emissions are dominated by PM 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

8. 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
UPM monitors to be located in areas with populations of 100,000 or more
Densely populated communities w/ 500 people/sq. mile are preferred for UPM monitoring locations

9. Summary of Staff Paper Recommendations for PM10-2.5
98th percentile standard ranging from ug/m3 OR
99th percentile standard ranging from ug/m3

10. 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

11. 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

12. 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 UPM 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

13. Next Steps EPA’s proposed rule is due December 20
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