A new Environmental Protection Agency report cited Southern California as one of the key problem areas for concentrations of ozone--a gas that is the principal component of smog--and said Los Angeles remains the only area of the country that still exceeds federal air quality standards for another major pollutant, nitrogen dioxide.
Although long-term progress has been made to improve the nation’s overall air quality, the report said, progress slowed from 1983 to 1984, in part because industrial growth resulted from expansion of the national economy.
According to the EPA, levels of sulfur dioxide, nitrogen dioxide, and dirt, dust and soot decreased by 2% nationwide between 1983 and 1984. At the same time, some improvements were registered for levels of lead, carbon monoxide and ozone.
“While considerable progress has been made controlling air pollution, it still remains a serious public health problem,” the report concluded.
J. Craig Potter, assistant EPA administrator for air and radiation, said that in addition to the economy’s expansion in 1984, the curbing of emission levels also shows that “we have achieved many of the major gains foreseen by the Clean Air Act.”
“We are now entering a new era where we must examine large numbers of smaller sources,” he told reporters.
Analyzed Six Pollutants
Potter said that an analysis of six major pollutants from 1975 to 1984 shows that the nation’s air quality has improved dramatically in the last 10 years.
“The flattening out of emissions and air quality numbers on a national average should not be interpreted to mean that our efforts are slowing down or that our programs are no longer working,” he said.
According to EPA, 79.2 million people live in counties where air quality levels violate federal ozone standards, compared to 61.3 million people for carbon monoxide, 32.6 million people for dust, dirt and soot, 7.5 million people for nitrogen dioxide, 4.7 million people for lead, and 1.7 million people for sulfur dioxide.
The report cited a major reduction in the levels for lead, which improved 70% in the last decade and 7% in the last year. At the same time, carbon monoxide levels improved 34% during the last 10 years, but only 1% last year.
Ozone Least Responsive
The EPA cited ozone as the pollutant that has been least responsive to progress. Ozone is formed by complex chemical reactions of volatile organic compounds, mainly hydrocarbons and nitrogen oxides reacting to sunlight.
The agency is considering whether to recommend tougher air quality standards for ozone, Potter said. According to the EPA, the highest concentrations of ozone are in Southern California, followed by the Texas Gulf Coast and the Northeast.
An EPA analysis of Los Angeles showed that: the level of dust, soot and dirt increased 21% from 1983 to 1984 (this large increase was attributed to unusually low concentrations of these pollutants in March and April of 1983 resulting from “unusually rainy and unstable conditions”); the level of lead dropped 60%, compared to a national average reduction of 45%; the level of sulfur dioxide dropped 25%, compared to a 15% reduction nationwide; the level of nitrogen dioxide decreased 10%, compared to a 7% nationwide reduction; and the level of carbon monoxide decreased by 34%, compared to a national average reduction of 10%.