CASAC Recommends Much Stricter Ozone Air Quality Standard, August 25, 2006
The Clean Air Scientific Advisory Committee (CASAC) has agreed that the the current air quality standard for ozone cannot be considered protective of public health and that EPA must lower the standard considerably to reflect studies show effects at and below the level of the current standard.
The Committee, meeting in Research Triangle Park, NC on August 24-25, 2006 made its comments on the review of the second draft EPA Staff Paper on the review of the ozone air quality standards.
It is highly unusual for a CASAC panel to reach a uanimous consensus on the level and form of the air quality standards.
The draft Staff Paper suggested that EPA could either retain the current 8-hour average ozone standard of 0.08 ppm, effectively 0.085 ppm due to rounding; or, adopt a standard of 0.07 ppm (effectively 0.075 ppm, due to rounding).
The CASAC members were unanimous that:
1. the current standard is not protective of public health and that the scientific evidence does not justify retention of the current standard as a policy option in the final Staff Paper. That is, the evidence from chamber studies and summer camp studies shows adverse respiratory effects in sensitive groups such as children with asthma at concentrations of 0.080 ppm and below, and epidemiological studies show effects at lower concentrations for endpoints like emergency department visits and mortality.
2. An additional significant digit should be added to the form of the standard to eliminate the rounding up of monitored concentrations. Monitoring instruments are sufficiently accurate to allow this.
3. The upper end of the range for consideration by the Administrator should be 0.070 ppm for an 8-hour average standard.
4. The lower end of the range should be 0.055 to 0.060 ppm, 8-hour average.
5. The risk assessment should not incorporate the concept of policy relevant background concentrations. EPA should calculate the risks of exposure to all ozone, whether manmade or natural. EPA should then compare the risks associated with exposure to various ozone concentrations.
The CASAC will be drafting a formal letter submitting their consensus comments to EPA. EPA is planning to issue a final Staff Paper by the end of October. The Committee has reserved the right to schedule a followup teleconference in mid-November to provide comments on the final staff paper if necessary.
The draft Staff Paper is available online at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_sp.html
A copy of the American Lung Association testimony at the CASAC meeting is attached.
Statement of Deborah Shprentz at August 24, 2006 CASAC Meeting
