EPA staff is recommending that the national air quality standard for fine particle matter be made tougher. A fact sheet on the “staff paper” is attached. A relevant excerpt is below. (Note the current annual standard is 15; the current 24-hour standard is 65, so EPA staff is recommending a range that includes a very significant tightening of the current standard.)
We will be urging the agency to set a standard at the low end of the suggested range because that would protect more people’s lives. This presents the Bush Administration with an historic opportunity to advance the cause of clean air.
…Consideration should be given to revising the current PM2.5 primary standards to
provide increased public health protection from the effects of both long- and shortterm
exposures to fine particles in the ambient air. Staff provides two alternative
approaches to establishing more protective suites of daily and annual PM2.5 standards.
- Retain annual standard at 15 mg/m3, together with a revised 24-hour PM2.5 standard
in the range of 35 to 25 mg/m3 (based a 98th percentile form for a standard set at the
middle to lower end of this range, or a 99th percentile form for a standard set at the
middle to upper end of this range)
- Revise annual PM2.5 standard, within the range of 14 to 12 mg/m3, together with a
revised 24-hour PM2.5 standard in the range of 30 to 40 mg/m3, with either the annual
or the 24-hour standard, or both, at the middle to lower end of these ranges
The full staff paper should be posted at this EPA web site later today: http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_cr_sp.html