"We can retrospectively estimate exposure levels for previous periods where direct data is lacking," says Davis, author of the paper titled "Recessions and Health: The Impact of Economic Trends on Air Pollution in California," which will be published in the October issue of the journal "American Journal of Public Health" (available online on August 16). "Without an accurate and historically relevant exposure model it is difficult to obtain estimates of lifetime human exposure which is critical in studies of chronic disease," she adds.
As an example of how the model could be used, Davis applied her formula to the years between 2006 and 2010when unemployment rose from 4.9 percent to 12.4 percent in California. According to the model, there would have been a 16.8 percent decline in ambient concentrations of carbon monoxide and a 12.2 percent decline in concentrations of nitrogen dioxide.
Her findings were not independently validated but Davis says that "the comparison provides perspective on what the predicted change in air pollution would be during a major economic downturn based on the results of the model."
Davis also looked for relationships between unemployment in the trucking industry and air quality. With trucking, she included estimates for haze, which is a marker for diesel-powered truck emissions. Here, she found a similar pattern of lower predicted pollution levels between 2006 and 2010.
Davis says that the results of her work provide evidence linking the economy to air pollution. In a 2010 study of air pollution levels and economic trends in New Jersey between 1971 and 2003, Davis found a similar relationship between pollution and unemployment.
"This is evidence that cyclical economic activity has an impact on concentrations of pollutants that the general public is exposed to," says Davis. "There is a net benefit for public health in terms of air pollution when unemployment rises."
|Contact: Alex Reid|