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Automated instrument measures oxidative potential of ambient particulate matter

12/17/2019 8:57:23 AM

Above: Collaborators Vishal Verma (right) and Haoran Yu stand in front of SAMERA. Not pictured: Joseph Puthussery

By Kristina Shidlauski

A unique property of air pollution – the oxidative potential (OP) of ambient particulate matter (PM2.5, or particles that have a size less than 2.5 µm) – has been shown to be linked with health disorders such as asthma, lung cancer and cardiovascular disease. Researchers at the Department of Civil and Environmental Engineering (CEE) at the University of Illinois at Urbana-Champaign, led by Assistant Professor Vishal Verma, have developed an automated instrument that can rapidly and comprehensively measure the OP of PM.

Oxidative potential is the capability of PM to generate unstable molecules that contain oxygen, known as reactive oxygen species (ROS), and/or consume antioxidants. Traditional methods of measuring OP are very laborious and time-consuming, Verma said, severely limiting the application of these methods to analyze large sample-sets and exploring their utility in health studies. To address this issue, the researchers developed the Semi-Automated Multi-Endpoint ROS-activity Analyzer (SAMERA), which greatly reduces the time and labor required to conduct the analyses.

“Our instrument provides a rapid and high-throughput analysis of the particulate matter oxidative potential,” Verma said. “The instrument analyzes one sample for five different endpoints of oxidative potential in less than three hours with minimal labor time of around five minutes. As a comparison, the manual analysis of one sample for all these endpoints of oxidative potential would take a whole day, about eight to ten hours.”

The data generated by SAMERA is very interesting, Verma said. For example, when researchers analyzed the samples collected from Chicago, Indianapolis, St. Louis and Champaign, Ill., on July 4, 2019, the results showed that oxidative potential of all five endpoints was significantly elevated due to fireworks emissions.

“We already know that cracking fireworks emits a lot of particulate matter in the air,” Verma said. “But this is the first time we show that this increase in the concentration of the particles is also accompanied by an increase in the oxidative potential. Now, assuming oxidative potential a closely related property with the health effects, it implies that the ambient air during and after July 4th celebrations is not very healthy to inhale. But, more toxicological studies need to be conducted to confirm this hypothesis.”

Verma anticipates that SAMERA will be very useful for regulatory agencies such as the United States Environmental Protection Agency (EPA), state EPAs, the California Air Resources Board and South Coast Air Quality Management Districts, as well as researchers studying ambient PM2.5 health effects. As large datasets are generated, SAMERA could also benefit future epidemiological studies for establishing the links between ambient air pollutants and health effects.

This work was funded by a National Science Foundation CAREER award. Verma and collaborators Haoran Yu and Joseph Puthussery, both CEE graduate students, published a paper on the project in Aerosol Science and Technology, available here.