States are working on State Implementation Plans (SIPs) to meet air quality standards set by the Environmental Protection Agency (EPA) under the Clean Air Act. Two criteria pollutants – ozone, a precursor of smog, and fine particulate matter (PM 2.5) – are of particular importance to state policymakers because of the cost of compliance and upcoming deadlines.
Issues of particular concern are EPA regulations that may be unintentionally causing more ozone rather than less, and a proposal by EPA staff to lower allowable PM levels even before compliance has started with the current standard.
This Research and Commentary collection offers: