Dirty air is shortening lives in Minnesota, study finds

Air quality improvements mandated by the passage of the federal Clean Air Act have added about six months to the typical Minnesotan’s life since the 1970s, according to data released this week by the Air Quality Life Index at the University of Chicago.

The data, which are updated annually, show that several more months could be added to the median Minnesotan lifespan if air quality standards were further tightened to levels recommended by the World Health Organization.

Minnesota’s numbers are similar to those for the U.S. overall, which has some of the world’s cleanest air. In some regions of the developing world, lives are cut short by five to 10 years due to poor air quality. The authors of the study call air pollution “the world’s greatest external risk to human health.”

The pollutant of most concern is fine particulate matter, more commonly known as smoke or soot. The particles are small enough to enter the bloodstream from the lungs, and to cross into the brain as well. 

Long-term exposure to these particles causes asthma, cardiovascular problems, dementia and other health issues. Even low-level, short-duration exposure can cause measurable declines in cognition and physical ability. 

Historically in the U.S., industry was one of the biggest producers of this type of pollution. But restrictions imposed by the Clean Air Act drastically reduced the volume of fine particles emitted by smokestacks and burning facilities. From 1998 to 2021, the average annual fine particle concentration in American air fell from 12.5 micrograms per cubic meter to 7.8.

But that number has been creeping upward in recent years, due in large part to record-breaking wildfire seasons that have released massive quantities of smoke into the atmosphere. During one 24-hour period in mid-June of this year, the smoke concentration in Minneapolis averaged 85 micrograms per cubic meter, roughly 10 times higher than the statewide annual average.

Those fires are likely to continue in the coming years, fueled by a warming climate and decades of careless forestry practices. 

In developing regions of the world, on the other hand, industry remains a potent emitter of smoke pollution. Wood-fired heating and cooking appliances add to the mix, creating indoor atmospheres where the air is even more polluted than it is outdoors.

All told, the average resident of Earth lost more than two years of life expectancy to dirty air in 2021, according to the Air Quality Life Index.