Implications of the new ozone National Ambient Air Quality Standards for compliance in rural areas

The U.S. Environmental Protection Agency (EPA) has recently promulgated new National Ambient Air Quality Standards (NAAQS) for ozone (O3). The new standard is based on an 8‐hour average O3 concentration instead of a 1‐hour average, as was the previous standard. Analysis of O3 concentrations measured at rural sites in the eastern United States in the Aerometric Information Retrieval System (AIRS) network, the Southern Oxidant Study's Spatial Ozone Network (SON), and EPA's Clean Air Status and Trends Network (CASTNet) during 1993–1995 indicates that 30–50% of these sites would have been noncompliant under the new standard, as compared with only 2–12% under the old standard. These results suggest that the new standard will thus require a major shift in emphasis in the nation's pollution control strategy from an urban‐centered focus to a more regional emphasis. This in turn will require the development of a more comprehensive, truly rural air quality monitoring network in coming years.