Air quality in Minnesota's largest urban area cleared a little in 2012, according to the Minnesota Pollution Control Agency.
The Twin Cities area averages about 10 air quality alerts most years. But in both 2011 and 2012, the number of alerts was only four -- three for ozone and one for fine particles.
MPCA's air monitoring program supervisor, Rich Strassman, says fine particle pollution has been declining in Minnesota, but the weather also plays a big role.
"We can probably attribute it to some fairly active weather in 2012, where the concentrations just didn't accumulate over multiple days like we've seen in the past," Strassman said.
The MPCA issues air quality alerts when pollution approaches levels that are unhealthy for sensitive groups -- the young, the old, and people with respiratory problems.
The calculations for the entire state are not complete yet. Strassman says since the federal government recently tightened air quality standards, Minnesota may have more "bad air days."
Follow Stephanie Hemphill on Twitter: http://www.twitter.com/mpr_hemphill