Traffic pollution is a known trigger of asthma symptoms, but a new study suggests a much more direct link: European researchers say that traffic pollution may cause 14 percent of childhood asthma, putting it on par with second-hand smoke.
The researchers reached their conclusions by applying data from existing epidemiological research, including a key study involving traffic in southern California, to the rates of children living close to similar traffic patterns in 10 European cities.
"The fraction of people living very close to busy roads was surprisingly high," said lead author Laura Perez. "We previously evaluated this for Los Angeles where far less live along such traffic corridors. When this finding was combined with existing results from epidemiological studies to evaluate the burden of this exposure, as traditionally done, we found that this exposure could be a quite relevant contributor to chronic diseases."
As the authors acknowledge in their study, published today in the European Respiratory Journal, applying data from the United States to European settings has some limitations. Pollution from vehicle traffic in the United States, for example, is different from traffic pollution in Europe. A higher percentage of European cars are diesel, for example, and there are different standards.