The nation’s ozone levels as a whole shot up 32 percent last year, while Minnesota’s air quality improved slightly, according to Environmental Protection Agency data.
But in recent weeks, the Minnesota Pollution Control Agency has issued several air pollution health alerts for Twin Cities residents, and since August, ground-level ozone has appeared in Minnesota rather than just usual high-smog suspects such as Houston and Los Angeles.
Ozone, when combined with other pollutants and photosynthesis, creates smog.
“Ozone is mainly a summer problem because the emissions given off only undergo the chemical reaction to turn into ground-level ozone when it reacts with hot, stagnant air,” Minnesota Pollution Control Agency spokeswoman Becky Helgeson said. “Our monitors show that it’s more of an urban problem because obviously that’s where more people are.”
Minnesota is one of six states that decreased their ozone violations in 2001. The other five were Alabama, Florida, Oklahoma, Rhode Island and Utah.
Pollution control agency officials said some of the main air pollution culprits are minute but toxic particles emitted by cars, trucks, buses, coal-fired power plants and fireplaces.
The agency also believes the wind carries pollutants from southern suburbs.
The particles are so small they easily get into buildings, so even going inside does not eliminate the threat, according to the agency’s findings.
Several medical studies have also shown a link between extended exposure to these pollutants and heart attacks, lung disease, asthma and cancer.
Nevertheless, University mechanical engineering professor Peter McMurry said he does not feel the recent spike is a cause for alarm because an accurate trend could only be identified after accumulating and studying at least 10 years of data.
“Concentrations of many air pollutants have decreased substantially since the Clean Air Act was passed,” McMurry said. Environmental Protection Agency documents show a 19 percent decrease in ozone between 1988 and 1997, McMurry said.
“There is still a possibility that the current trend might continue,” he said.
Causes for concern
Coal plants are the single largest source of air pollution and greenhouse gas emissions in Minnesota, according to the nonprofit Minnesotans for an Energy-Efficient Economy.
These plants are responsible for 20 percent of nitrogen, 63 percent of sulfur, 62 percent of lead and 43 percent of mercury leaked into the air, according to the group’s findings.
According to a 1995 permit granted to the northeast Minneapolis Riverside plant, which is owned and operated by Xcel Energy, the facility is legally allowed to release 10,000 pounds of hydrochloric acid, 16,000 pounds of nickel, 300,000 pounds of barium, 23,000 pounds of sulfuric acid and 27,000 pounds of fluoride into the air every year.
Twin Cities residents suffer 66,000 asthma attacks every summer because of ozone caused by dirty power plants, according to the Washington-based nonprofit Clear the Air. The group also credits these plants with doubling the level of nitrates in the Mississippi River since 1965.
But McMurry said “it is inaccurate to suggest that there is a biggest (single) culprit.”
One possible cause of Twin Cities air pollution is urban sprawl. A recent Sierra Club report listed the Twin Cities area as among the 10 cities most threatened by poor city development planning.
“I think the ozone in the Twin Cities will only increase as the congestion on the roads increases,” University soil, water and climate professor Terence Cooper said.
But McMurry said cars produce less pollution than in previous years.
“Certainly urban sprawl can contribute,” he said. “But reduced vehicular emissions have led to lower concentrations of air pollutants.”
Helgeson said more vehicles on the road traveling longer distances mean more pollution warnings.
“In the past, no one would dream of commuting to Minneapolis from St. Cloud,” she said. “Add to that the huge popularity of (sport utility vehicles), who aren’t required to abide by any significant emissions standards.”
Helgesen said several sources contribute to the current emissions spike.
“Still, we’re in much better shape than other cities our size,” she said.
Federal solutions
The George W. Bush administration has been pushing its controversial Clear Skies Initiative for more than one year. The plan puts a shrinking cap on power plant pollution but lets those utilities trade so-called “right to pollute” credits among themselves.
The EPA claims this plan would reduce pollution by 58 percent by 2008 and by almost 67 percent by 2018. Environmental groups counter that bigger gains could be made by enforcing current air pollution laws.
“I do not think the (Clear Skies) initiative will have a positive impact on air pollution,” Cooper said. “It allows too much of the same problems of the past.”
McMurry said that based on what he knows about the plan, it will be a good approach.
“Companies will be given some freedom to figure out the most economically sensible approach for meeting those (pollution) targets,” he said.
Nathan Hall covers the environment and transportation and welcomes comments at [email protected]
