Bend fares well in pollution study

Published 12:00 am Monday, April 21, 2014

WASHINGTON — The difference in concentration of the pollutant nitrogen dioxide between where whites and non-whites live is less pronounced in Bend than in other cities in Oregon, according to a new study by researchers at the University of Minnesota.

Bend’s levels of nitrogen dioxide, also called NO2, were 10.3 parts per billion in neighborhoods where people of color live and 10.1 ppb in white neighborhoods, a difference of .2 ppb, the study found.

In Oregon cities, Salem (9.4 ppb and 8.6 ppb; .8 difference) had the biggest disparity, followed by Portland (11.9 ppb and 11.3 ppb; .6), which had the highest levels overall. Corvallis (7.1 ppb, 6.7 ppb; .4), Eugene (9.1 ppb, 8.8 ppb; .3) and Medford (8.8 ppb, 8.5 ppb; .3) were the other Oregon cities included in the study.

Statewide, Oregon’s NO2 levels were 9.4 ppb in communities of color and 8.0 ppb in white neighborhoods, a difference of 1.4.

In 1971, the Environmental Protection Agency listed NO2 as one of six “criteria pollutants” that must be monitored and established the maximum annual average concentration at 53 ppb. NO2 is linked to respiratory issues and can exacerbate the onset or intensity of asthma.

NO2 is produced by combustion of fossil fuels, often by motor vehicles or coal-fired power plants.

Timothy VanReken, an assistant professor at Washington State University’s laboratory for atmospheric research in the civil and environmental engineering department, said he wasn’t surprised by the new study’s findings because socioeconomically challenged groups often live near roadways and in industrial areas.

“It was a bit surprising that it was quite as large a difference as it was (between the two groups),” he said.

In the Pacific Northwest, meteorology and mountain topography have a big impact on how pollutants are diluted in the atmosphere, he said.

Particularly in valley areas, the air doesn’t mix as well in the colder winter weather, he said. Air that’s close to the surface can stay there, keeping pollutants from dispersing, he said.

Overall, Oregon’s air is “quite clean,” he said.

As an urban center, Bend stands to have higher concentration of NO2 than rural areas, where fewer cars are driven in a wider area, he said.

“In any urban area, you would expect to have higher concentrations than in the remote areas around it,” VanReken said.

While NO2 is itself a pollutant, it is often used as a surrogate marker for other types of pollution during monitoring, said Ron White, the director of regulatory policy at the Center for Effective Government in Washington, D.C. He also teaches at Johns Hopkins University’s school of public health.

If NO2 is present, that likely means that other pollutants are as well, he said.

Since the EPA put its standards in place, NO2 levels have continued to drop, largely because of improved emission standards on newer cars, White said.

“The issue is whether the standard that is in place is adequate to protect public health,” he said. “There are health researchers that feel there is a concern with exposure to NO2 even at the level we are looking at these days as being ‘safe.’”

The EPA now requires NO2 monitoring near roadways in large metropolitan areas, he said.

“Over the years, what’s been found is people who live close to roadways are exposed to much higher levels of pollution from cars and trucks,” he said. “Once these monitors start developing data that researchers can use, I suspect what you’re going to find is levels are much higher (there).”

In 2010, the EPA imposed stronger standards on NO2, setting the maximum allowable level for one hour at 100 parts per billion. The maximum annual average remained at 53 ppb.

“This suite of standards will protect public health by limiting people’s exposures to short-term peak concentrations of NO2 — which primarily occur near major roads — and by limiting communitywide NO2 concentrations to levels below those that have been linked to respiratory-related emergency department visits and hospital admissions in the United States,” the EPA’s announcement states.

While NO2 levels may continue to drop as emission standards improve, it will take years to notice the effects, said Deborah Bennett, an associate professor of environmental and occupational health at the University of California, Davis.

“It is difficult for (the) EPA to regulate motor vehicles for emissions (as a means of reducing pollution) because people can keep their cars as long as they want, and can drive as much as they want,” she said. “Any improvements made now aren’t instantaneous but integrated over time.”

Because different population centers have different conditions — traffic, neighborhoods near roadways, weather patterns — efforts to reduce NO2 pollution may have to be individually tailored for various locations across the country.

“We know that we have unacceptable levels of pollution in some of the areas, and we need to continue to work to reduce those somehow,” she said. Particularly in high traffic areas, “We do keep a lot of diesel trucks on the road for extended periods of time.”

— Reporter: 202-662-7456, aclevenger@bendbulletin.com