Science Wednesday: OnAir: Tunneling for Air Pollution Answers

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Lately, John Godleski has spent a lot of time underground.

When I visited Harvard in December though, he surfaced for a chat with me about his unique research.

Along with colleagues at the Harvard Particulate Matter Research Center, Godleski has set up air pollution monitoring equipment inside a busy tunnel in the Northeast.

Part of the Toxicological Evaluation of Realistic Emission Source Aerosol, his study aims to assess differences between the health effects of exposure to particles directly from car exhaust (primary), and particles from exhaust that have transformed in the atmosphere (secondary).

The underlying hypothesis of the project is that breathing in particles that come directly from a vehicle might induce different health effects than breathing in particles that have spent time in the atmosphere, where they come into contact with sunlight.

To test the hypothesis, Godleski and his colleagues developed a photochemical aging chamber that essentially mimics real-world atmospheric conditions with simulated sunlight.

Exhaust from cars is fed into the chamber first with the artificial sun-lights switched to “off” and to then to “on.” This produces two types of output: exhaust with just primary particles (lights off), and exhaust with both primary and secondary particles (lights on).

Project scientists then conduct lab studies to look for differences in resulting health outcomes.

Preliminary findings suggest that the “lights on” particles, representing particles that have come into contact with sunlight, cause more lung inflammation and more potentially harmful oxidative activity in the body.

Since secondary particles in the air are ubiquitous, understanding their health impacts is extremely important.

“Though some people are involved in what directly comes out of a vehicle or a power plant, everybody is exposed to what happens to those particles once they are in the air,” Godleski explained.

Collection of exhaust particles directly from the tunnel makes this study especially representative of real-world particle exposure.

“If we go to a tunnel,” he continued, “we can get a mixture of vehicle output—we can get cars, we can get trucks, and we can get something very representative of what people ultimately may breathe. It gives us access to a mixed vehicle effluent in a way that nothing else does.”

This research is a critical step toward understanding the health effects of real-world airborne particle exposure. We will continue to report findings as Godleski continues to dig for answers.

About the Author: Becky Fried is a student contractor with EPA’s National Center for Environmental Research. Her OnAir posts are a regular “Science Wednesday” feature.

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