ABSTRACT
"Nonattainment" has a very precise meaning as defined in the Clean Air Act. Chicago, Atlanta, Portsmouth, and most other nonattainment areas each exceeded the standard an average of less than one percent of the total monitored hours. Of course, "all monitor hours" include nighttime hours and winter months, which typically do not present an ozone problem. Epidemiological research on pollutants usually examines hospital and doctor records to determine if there is a relationship between a given health effect and some environmental factor such as elevated ozone levels. Some factors contributing to elevated ozone levels are beyond human control. Because ozone moves with air masses, ozone levels can be higher in suburban or rural areas than in urban areas. Moreover, elevated levels of ozone can persist longer in outlying areas because of the absence of nitrogen oxide for chemical "scavenging," breaking down the ozone molecule into harmless oxygen.
