There are more ways that auto emissions in large cities are impacting air quality and human health than previously thought, according to research from Texas A&M University and elsewhere.
The findings of A&M distinguished professor of atmospheric sciences Renyi Zhang — along with others from the University of Texas at Austin, Johns Hopkins University, several Chinese universities and more — were published this week in the Proceedings of the National Academy of Sciences. Their research centers around auto emissions in urban areas — especially Beijing, which has some of the highest levels of pollution from auto exhaust globally.
The study revealed that aromatic organic compounds from auto exhaust form lots of ultrafine particles, which are one-thousandth the width of hair and can lead to poor air quality, health problems and potentially birth defects. Zhang told Texas A&M Today that the particles can form in any city, and residents who live near highways and congested roads are the most vulnerable to the negative health consequences.
“This has been an emerging area for research,” Zhang said to Texas A&M Today. “Ultrafine particles can penetrate easily through human lungs and reach many vital organs. The impacts of ultrafine particles on human health can be far-reaching. Currently, ultrafine particles are unregulated. They can be present in high concentrations, but you still see blue sky.”
According to Texas A&M Today, the U.S. Environmental Protection Agency’s air quality standards limit the mass concentration of PM2.5, which are particles smaller than 2.5 microns. However, the study found that ultrafine particles don’t make up much of the PM2.5 and tend to be produced more efficiently when the atmospheric PM2.5 levels are low.
Zhang told Texas A&M Today that reducing PM2.5 in an effort to improve air quality could make pollution of ultrafine particles worse. Zhang said it is important for both types of particles to be reduced simultaneously.
“The problem of ultrafine particles is as important in China as in the U.S.,” Zhang said in A&M Today.