"An EPA advisory panel has delivered its final word in a pivotal review of national soot standards, with most members standing by a set of preliminary recommendations to strengthen both the annual and daily exposure limits.
“The results support the conclusion that the current primary annual PM2.5 standard does not adequately protect public health,” the Clean Air Scientific Advisory Committee (CASAC) wrote in a newly released letter to agency chief Michael Regan that uses a technical term for soot. All seven members agreed with the conclusions of EPA career staff that the evidence warrants some tightening of the current threshold, albeit with some disagreement on how far to go, according to the letter and accompanying report.
The panel also makes other suggestions for changes to the agency’s regulatory treatment of soot, including that EPA “consider the implications” of its traditional designation of wildfires as “exceptional events” outside of regulators’ direct control. Under that framework, states can effectively get waivers for wildfire-related soot emissions that could otherwise pose compliance problems."
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