EPA details questions for primary NOx NAAQS review

EPA is outlining questions it wants answered in its forthcoming review of “primary” health-based national ambient air quality standards (NAAQS) for nitrogen oxides (NOx), as the agency updates its scientific assessment and policy recommendations for curbing the pollutant. In its Integrated Review Plan (IRP) “volume 2” document released March 18, EPA poses a series of questions that it will seek to answer in its forthcoming integrated science assessment (ISA) for NOx, which will then inform a policy assessment (PA) document...