Monday, October 17, 2011

EPA flies white flag again -- this time over big-particle pollution...

....cleverly packaged by opponents as benign-sounding “farm dust.”

EPA noted in letter to Congress that it plans to propose no change in the existing standards for big-particle pollution, or “PM 10”

Compare to what EPA’s science advisers had said, in arguing that existing standards are too weak. EPA summarized the scientists’ advice in a recent policy assessment document:

p 3-23
3.2.2 CASAC Conclusions and Recommendations
Following their review of the first and second draft PAs, CASAC provided advice and recommendations regarding the current and potential alternative standards for thoracic coarse particles (Samet, 2010c; Samet, 2010d). With regard to the current PM10 standard, CASAC concluded that “the current data, while limited, is sufficient to call into question the level of
protection afforded the American people by the current standard” (Samet, 2010d, p. 7). In drawing this conclusion, CASAC noted the positive associations in multi-city and single-city studies, including in locations with PM10 concentrations below those allowed by the current
standard. In addition, CASAC gave “significant weight to studies that have generally reported that PM10-2.5 effect estimates remain positive when evaluated in co-pollutant models” and concluded that “controlled human exposure PM10-2.5 studies showing decreases in heart rate
variability and increases in markers of pulmonary inflammation are deemed adequate to support the plausibility of the associations reported in epidemiologic studies” (Samet, 2010d, p. 7). Given all of the above conclusions CASAC recommended that “the primary standard for PM10
should be revised” in order to increase public health protection
(Samet, 2010d, p. ii and p. 7).
The full letter by the scientists is at$File/EPA-CASAC-10-015-unsigned.pdf

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