CASAC Panel Members Fault EPA Plan For NOx-SOx-PM Risk Assessment

摘要

Members of EPA's Clean Air Scientific Advisory Committee (CASAC) are faulting the agency's plan for assessing the environmental harms from emissions of nitrogen oxides (NOx), sulfur oxides (SOx) and particulate matter (PM), warning it uses a confusing and narrow approach that echoes problems from a prior NOx-SOx combined review. "This approach doesn't seem cogent, 1 can't grasp it. It just doesn't seem convincing," said CASAC panelist and environmental consultant Praveen Amar. He was discussing the agency's proposed quantitative risk and exposure assessment (REA) to support its review of the "secondary" national ambient air quality standards (N AAQS) for the three criteria pollutants. Secondary standards are designed to protect the environment, unlike "primary" health-based NAAQS. Amar was one of several members of a CASAC panel at a Sept. 5-6 meeting in Durham, NC, to address the REA plan. Panelists offered broad support for EPA's goal to evaluate risks of the three air pollutants using a metric based on deposition of air pollution in waterbodies - but raised doubts about the viability of the agency's chosen approach.