On November 25, 2014, the U.S. Environmental Protection Agency (EPA) proposed a new, more stringent national ambient air quality standard (NAAQS) for ground-level ozone, the main component of smog. National Ambient Air Quality Standards for Ozone, _____ Fed. Reg. ____ (proposed Nov. 25, 2014). Ozone is not emitted directly into the air but results when emissions of precursors, such as nitrogen oxides, volatile organic compounds, carbon monoxide and methane, “cook” in the sun. Typical sources of these emissions include electric utilities and motor vehicle exhaust. Ozone causes or aggravates a variety of respiratory conditions, such as asthma, emphysema and bronchitis. The federal Clean Air Act requires EPA to adopt primary and secondary NAAQS for six “criteria” pollutants, including ozone, and revise the standards every…