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Mila Koumpilova, Published June 28 2009

Study finds North Dakota air less likely to cause cancer

North Dakota and northwestern Minnesota did well in a new study of cancer-causing air toxins, even as Cass County showed elevated levels of the substances compared to the rest of the state.

In a U.S. Environmental Protection Agency report examining 80 toxins, North Dakota boasts the second cleanest air in the country, trailing closely only Wyoming. Residents on average faced an excess cancer risk of 16.7, which stands for the number of additional people per 1 million residents expected to develop cancer because of their exposure to air pollution.

That compares to a national average of 36, or more than 50 in New York and Oregon, the states topping the air toxics level list.

Minnesota ranked right in the middle of the pack, with an excess risk of 31.1. Most of Minnesota, including Clay County, faces a low, 10 to 20 excess cancer risk. Risk is higher in the Twin Cities and Duluth Harbor areas, into the 40 to 50 range in some Twin Cities neighborhoods.

The Environmental Protection Agency uses the study, called the National-Scale Air Toxics Assessment, to track parts of the country whose residents face the greatest health risks from air pollution. It’s based on 2002 emissions of 80 toxins from automobiles, industry and other sources.

According to the study, 2.2 million people live in 600 neighborhoods – none of them in North Dakota or Minnesota – where the level of toxins exceeds that the government deems acceptable.

Jim Semerad, a manager at the North Dakota Health Department’s Division of Air Control, said two main factors help explain the state’s low air toxin level. For one thing, the state’s flat, wind-swept topography makes for cleaner air than a place with many valleys and ravines that trap pollution. And also with automobiles at the top of cancer-causing pollutant sources, the state’s low population helps.

“Oftentimes we think industry only is responsible for pollution, but we play a significant role in our own air quality,” Semerad said. “We can’t always point a finger at somebody else.”

In turn, Cass County’s higher population density predictably accounts for higher levels of toxins.

“Gasoline and diesel are a toxic witch’s brew of chemicals,” said Robert Moffitt, communications director at the American Lung Association of Minnesota, which advocates for wider use of biodiesel in the state. “The problem is sitting in our driveways.”

Moffitt noted that, whereas there is no completely safe level of cancer-causing toxins, Fargo did score below the national average – and was deemed North America’s cleanest air city by the association’s State of the Air study earlier this year.

As for the Minneapolis-area elevated levels, Moffitt said, “We’ll be talking about these in the Twin Cities quite a bit.”

According to the Minnesota Pollution Control Agency, mobile sources, from cars to lawn equipment, account for more than half of air toxics in the state. The rest is almost evenly split between industrial sources and so-called area sources, such as home furnaces, woodstoves and dry cleaners.

Readers can reach Forum reporter Mila Koumpilova at (701) 241-5529