Summary of EPA Proposal to Revise the PM NAAQS and Draft WRAP Technical Comments

PM2.5 Annual primary standard currently 15 ug/m3 No change in the proposal Taking comment on 13 or 14 ug/m3 24-hr primary standard currently 65 ug/m3 Proposal would reduce to 35 ug/m3 Taking comment on 30-35 ug/m3 Secondary standards would be equivalent Taking comment on urban visibility standard of 20-30 ug/m3 averaged over 4-8 daylight hours

PM2.5 Draft WRAP technical comments support secondary standard for urban visibility Would have direct benefits to Class I areas impacted by urban areas

PM10 Proposal would revoke annual standard in all areas Proposal would revoke 24-hr standard in all areas except in urbanized areas where: Population is at least 100,000, and At least one monitor is violating the standard 24-hr standard would remain in areas above until PM10-2.5 designations occur

Locations where EPA proposes to retain the 24-hr PM10 standard.

Current PM10 nonattainment areas where EPA proposed to revoke the 24-hr standard.

69 PM10 nonattainment and maintenance areas in the WRAP region.

PM10 EPA taking comment on retaining 24-hr standard in areas with population less than 100,000 Draft WRAP technical comments support elimination of 100,000 population distinction

PM10-2.5 PM10-2.5 defined as: Any ambient mix of PM10-2.5 that is dominated by resuspended dust from high-density traffic on paved roads and PM generated by industrial sources and construction sources. This definition excludes any ambient mix of PM10-2.5 that is dominated by rural windblown dust and soils and PM generated by agricultural and mining sources. Agricultural sources, mining sources, and other similar sources of crustal material shall not be subject to control in meeting this standard.

PM10-2.5 The indicator is not defined or limited to any specific geographic area, but includes a mix of PM10-2.5 in any location that is dominated by these sources. 24-hr primary standard set at 70 ug/m3 3-year average of 98th percentile No annual primary standard Secondary standards equivalent to primary Does this protect visibility?

PM10-2.5 EPA taking comment on: Alternative approaches for selecting level of PM10-2.5 standard Selecting an unqualified PM10-2.5 indicator Alternative approaches to retaining the 24-hr PM10 standard

Draft WRAP Technical Comments on PM10-2.5 Standard Eliminate distinction of urban PM10-2.5 Eliminate exemption for ag, mining, and rural windblown dust Without eliminating these two provisions, the ability to make reasonable visibility progress in Class I areas will be jeopardized EPA should adopt a 24-hr PM10-2.5 standard in the range of 50-135 ug/m3

Percentage of IMPROVE sample days between 1997 and 2002 when haze from dust (coarse mass plus fine soil) is the largest component.

Annual PM10-2.5 concentration from the IMPROVE network for 2004.

Modeled windblown dust emissions for 2002.

Average 2002-04 98th percentile PM10-2.5 concentration values for the IMPROVE Network sites.

PM10-2.5 98th percentile concentrations for sites with three year mean values above 30 μg/m3.

Chiricahua NM Typical Visibility Day

Chiricahua NM Worst Visibility Day

Chiricahua NM Typical Visibility Day + 135 ug/m3 of PMcoarse

Chiricahua NM Typical Visibility Day + 100 ug/m3 of PMcoarse

Chiricahua NM Typical Visibility Day + 70 ug/m3 of PMcoarse

Chiricahua NM Typical Visibility Day + 50 ug/m3 of PMcoarse

PM10-2.5 Monitoring Only required in MSAs > 100,000 people 0-5 sites per MSA 225-250 sites across 150 MSAs Emphasis on continuous mass conc. monitors Additionally … Non-required PM10-2.5 concentration sites to assess urban/rural differences 50-100 speciation monitors at urban/rural sites

PM10-2.5 Monitoring Draft WRAP technical comments Too little emphasis on non-urban areas Too little emphasis on speciation EPA should endorse use of IMPROVE PM10-2.5 monitoring and support speciation of IMPROVE PM10-2.5 samples