EPA finalizes science assessment for ‘secondary’ NOx, SOx standards

October 16, 2020
EPA staff has released its final integrated science assessment (ISA) of the ecological effects of nitrogen oxides (NOx) and sulfur oxides (SOx), and some particulate matter (PM) ecosystem effects, advancing overdue reviews of the “secondary” national ambient air quality standards (NAAQS) for the pollutants. The final ISA , announced in a Federal Register notice scheduled for publication Oct. 19, appears little changed from an earlier draft already approved by EPA’s Clean Air Scientific Advisory Committee. But issuance of the...


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