The news pages hadn't been kind to the agency in 2005, with stories suggesting the MPCA favored industry over environmental groups in setting new state mercury regulations. Meanwhile, state senate hearings have been investigating whether the agency persecuted a whistle-blowing MPCA scientist who'd targeted 3M, Corrigan's former employer. Yet Corrigan saw happier signs in the air. Specifically, during a river swim with her two kids, Corrigan saw bald eagles, whose population has increased 28 percent, Corrigan writes, from just five years ago.
Granted, the recovery of this great carrion bird started with the federal ban on DDT in 1972. But Corrigan found much else to be excited about in the state's air and water: "The Twin Cities is one of only three major metropolitan areas in the country that meets all federal ambient air quality standards, and Minnesota is among only 11 states meeting those same stringent standards."
It was an interesting statistic to champion given that in 2005 Minnesota also registered its worst air day ever. In fact, a review of the MPCA monitoring data from last year suggests that Minnesota does not have "good" air. What it has most days, according to the Environmental Protection Agency's Air Quality Index, is "moderate" air.
The AQI measures ground-level ozone, sulfur dioxide, carbon monoxide, and fine particles (PM2.5), and categorizes the results under five headings: good, moderate, unhealthy for sensitive groups, unhealthy (for all), and very unhealthy. At the end of 2005, the Twin Cities metro had registered 191 moderate days 166 good ones and 5 that were unhealthy for sensitive groups.
And then there were the three days at the end of January and the beginning of February when a climate inversion over most of the central and northeast United States caused particulate matter readings to spike into the red zone--unhealthy for all.
The alerts received steady media play and they highlighted a paradox in the MPCA's public outreach campaign. On one side, the agency hopes to convince Minnesotans to limit their personal pollutants--snowmobiles, fireplaces, and, most of all, tailpipe emissions--when the air grows foul. (The MPCA has no plan--or perhaps no will--to increase limits on industry and utility emissions on air alert days.) On the other side, air alerts on the five o'clock news may stir an alarmed public to ask why the MPCA hasn't kept pollution under control.
"The public has a sense because we see alerts we didn't see as kids, that the air quality is getting worse," says Rick Strassman, air quality monitor supervisor at the MPCA. "But that's not the case. We're monitoring for new pollutants. At the same time they promulgated the new particle standards, the EPA made a tighter, more restrictive standard for ozone. And as a combination of the two, we've seen a higher number of alerts for both particles and ozone in the last five or six years."
Strassman goes on to explain that the MPCA didn't begin monitoring for pm2.5 pollution until 1999; undoubtedly, the public has been sucking down ugly stuff since the beginning of the industrial age. Meanwhile, levels of mercury and lead have fallen dramatically--despite the boom in the population and the increase in road congestion. And the planned gas conversion of two coal-fired power plants, the Riverside facility in Minneapolis and High Bridge in St. Paul, should eliminate the largest fixed source of small particle pollution. Though the air may be cleaner than it was a decade or two ago, Strassman acknowledges, "that's kind of been a tough message to sell."
Christopher Childs, who tracks air pollution for the North Star chapter of the Sierra Club, isn't buying such a rosy picture of air quality. "I was very concerned about the major air quality alert we had back in the winter," Childs says. "That's a real warning sign."
While he agrees that the coal-plant conversions will have a dramatic effect on the skies, he looks gloomily at the standing parade of cars stacking up on the ring roads. "It's going to take some serious advances in public transportation to make a dent in pollution from our vehicles," Childs says.
Ultimately, the Twin Cities aren't at risk of going into non-attainment--that is, failing to meet EPA air standards--which would trigger strenuous, and expensive, regulation of industry and transport. Yet even low levels of pollution can prove damaging to vulnerable populations: children, the elderly, and individuals with cardiovascular and pulmonary disease. Dr. Christine Ziebold, a Minneapolis pediatrician who also has a Ph.D. and a master's in public health, cites a 2004 statement from the American Academy of Pediatricians. "National air quality standards," she says, "are not protective of children's health and doesn't consider the special developmental vulnerability of children."
"For instance," she continues, "80 percent of the alveoli--the tiny air bubbles that make up the lungs--are formed post-natally. There's enormous growth, and during the early post-natal period the lung is very susceptible to damage."
While the AQI handily offers the public a color-coded way to gauge pollution levels, hour by hour, the health consequences, Ziebold argues, don't follow such a clear threshold. "Because of the enormous number of people involved," she says, "small risks equal a significant risk for the population."
Or as Corrigan wrote at the end of her cheery op-ed, "Maybe we can't see the difference, but the eagles can."