Study examines freeway pollution

Area residents living near freeways are being exposed to higher levels of vehicle pollution than are safe, according to research findings by Portland State professor Linda George.

George, who is involved with several educational and research studies around the Portland area, is focusing on neighborhood-scale air-quality modeling, which monitors air quality by taking readings near a pollution source. The number of pollutants in the air around area freeways is much higher than state-recommended levels, George said.

“Freeways are a major pollution source due to the high vehicle density,” she said. “The closer you are to a pollution source the greater your exposure to pollution.”

An associate professor of environmental sciences, George conducts her research on freeway area pollution with diffusion tubes, used to collect and analyze samples of air from affected areas.

The tubes are left at points along the freeway and collected after two weeks for analysis, George said. She said tubes left along the freeway pick up nitrogen dioxide, which is used as a marker to measure the level of pollution.

This is a very time consuming and labor-intensive process, George said.

George said she is also collaborating with other PSU professors to develop a sensor to detect nitrogen dioxide, which can then be used with a wireless sensor network that would provide continuous data from points along the freeways.

Measurements taken help examine the health impact of the pollution on the area populations near freeways, George said. She also said a prototype for the sensor is being developed by a PSU graduate student.

“My models show a huge concentration of pollutants along the freeway, with the concentration decreasing as we move away from it,” George said.

According to George, vehicle emissions contain nitrogen dioxide, as well as diesel particulate matter, known to cause respiratory problems, and Benzene, a carcinogen found in cigarette smoke and in gasoline.

A study with Dean Atkinson, PSU associate professor of chemistry, found the average Benzene levels in northeast Portland to be around five times the state-recommended level, George said. That amount is only an average–there are also pockets with much higher levels of Benzene, she said.

George recommended that concerned residents use vehicles less to help keep pollution down.