Researchers at Oregon State University performed lab experiments that mimicked the chemical reactions that occur from the combustion and resulting exhaust of car engines and backyard grills. They found that these chemical reactions, though already known to produce certain compounds, also produced previously undiscovered compounds, which they found could be hundreds of times more likely to cause DNA mutations leading to cancer, according to a new study.
Any type of combustion, from the burning of a wooden stove to that of a cigarette is known to create compounds known as polycyclic aromatic hydrocarbons (PAHs). There are about 10,000 different compounds that are considered to be PAHs, including Benzopyrene, Anthracene, and Fluorene. And while it’s believed that PAHs might have damaging health effects in highly polluted areas, where their concentrations are high, the levels at which they pose a threat still aren’t known.
The researchers, however, found that when some PAHs interacted with nitrogen, to form NPAHs, their ability to cause DNA mutations — known as mutagenicity — increased to between six and 432 times more than their parent PAH when combined with one nitrogen group, and to between 272 and 467 times more when combined with two nitrogen groups.
“Some of the compounds that we’ve discovered are far more mutagenic than we previously understood, and may exist in the environment as a result of heavy air pollution from vehicles or some types of food preparation,” Staci Simonich, a researcher of the study and professor of chemistry and toxicology at the university’s College of Agricultural Sciences, said in a press release. Citing technical reasons with the way that testing is conducted for mutagenicity, the researchers said that these toxicity levels could even be understated, and could actually be much worse. However, they “don’t know at this point what levels may be present,” Simonich said, and plan on conducting further experiments.
Simonich and her colleagues first looked into the effects of PAHs leading up to the 2008 Beijing Summer Olympic Games. The team conducted several studies to assess what type of effect the city’s air quality would have on athletes and visitors.
China’s major cities have become notorious for severe air pollution caused by factories, automobiles, outdoor grills, and fireworks. In October, pollution levels reached 40 times higher than the World Health Organization’s (WHO) safety standard in the northeast city of Harbin, causing all such operations to be temporarily shut down. WHO announced last year that air pollution — specifically particulate matter, which can stick in the lungs — can cause cancer.
Source: Simonich S, Dashwood R, McIntosh M, et al. Novel Nitro-PAH Formation from Heterogeneous Reactions of PAHs with NO2, NO3/N2O5, and OH Radicals: Prediction, Laboratory Studies, and Mutagenicity. Environmental Science & Technology. 2013.