Every day, the mass burning of coal, gasoline, diesel, and other fossil fuel emits vast amounts of nitrous oxides (NOx) into our air. These compounds react with water, ammonia, and other chemicals in the atmosphere to form small particles that penetrate deep into our lungs. Besides causing emphysema and bronchitis, NOx emissions drive up hospital admissions for asthma, respiratory disease, and heart distress, as well leading to earlier deaths. But with our air so filled with chemicals, how can we know if one particularly bad factory is causing the damage?
Researchers now have a way to "fingerprint" air pollution such as NOx emissions. By studying the unique molecular signature of emissions, scientists from the University of Pittsburgh and the Electric Power Research Institute (EPRI) located the precise sources of pollution across the country by tracking it back to individual stacks.
"We’ve been mapping the isotopes of nitrogen oxide deposition products across the nation," said principal investigator Emily Elliott, assistant professor in the University of Pittsburgh’s Department of Geology and Planetary Sciences in a release. "These ‘isoscapes’ can only be interpreted with fingerprint data like the isotopic signatures collected in this study."
It works by looking at the molecular configuration of nitrogen from individual smoke stacks. Sampling coal-fired power plants allowed researchers to study how different pollution-control technologies affected the proportions of nitrogen isotopes in flue gasses. These readings were then used to trace back the sources of NOx compounds deposited from the atmosphere, according to the study published in Environmental Science and Technology.
NOx is now on the decrease. Power plant emissions have fallen more than 70% since 1990, (and 40% since 2005), reports the EPA, which began regulating the pollutant in 1971. Yet those living close to major roads and highways (about 13% of America), and almost everyone in L.A., continues to receive unhealthy doses.
This new research at least starts to reveal the exact sources of such pollution. The next step, says the University of Pittsburgh, is to look beyond coal power plants, and see how much NOx come from other sources, such as cars, off-road vehicles, animal feed lots, and fertilizer.