Comment submitted by Kenneth Cohen, Missouri Coalition for the Environment

I am a resident of the state of Missouri. The Clean Air Act requires the EPA to set National Ambient Air Quality Standards (NAAQS) at levels that protect public health with an adequate margin of safety (CAA § 109(b)(1)). Sufficient monitoring for compliance with the NAAQS is essential to achieve the goal of protecting sensitive subpopulations, like children and pregnant women, with an adequate margin of safety. I support EPA's proposed 0.5 tons per year threshold for monitoring.