The hazy Minneapolis skyline behind commuters on I-35W back in 2003.

Judy Griesedieck, Star Tribune file

Wildfire smoke sparks air alert in Twin Cities

  • Star Tribune
  • June 26, 2012 - 8:54 PM

A warm sunny day combined with southwest winds carrying wildfire smoke from the west are expected to raise ozone levels to near unhealthy levels on Wednesday in the Twin Cities and Rochester, the state Pollution Control Agency announced.

That could put some sensitive people at risk, including those with respiratory conditions like asthma, the elderly, children and people who engage in high exertion activities outside.

On Wednesday temperatures are forecasted to be in the low 90s with clear sunny skies and moderate southwesterly winds carrying wildfire smoke. As a result, the Air Quality Index (AQI) is forecasted to reach 97 AQI in the Twin Cities and 93 AQI in Rochester on Wednesday, which is just below air quality conditions, the MPCA said. The alert will extend from about noon on Wednesday to midnight.

Ozone concentrations will be the lowest in the morning hours and will gradually rise in the afternoon and early evening. The levels will begin to decline overnight. Increased winds speeds and slightly cooler temperatures are expected to improve air quality conditions to an AQI in the mid-60's on Thursday.

Ozone is produced by a chemical reaction between volatile organic compounds and oxides of nitrogen. These pollutants are released from motor vehicles, lawn and garden equipment, paints and solvents, refueling stations, and other activities that require fuel combustion.


Josephine Marcotty • 612-673-7394

© 2018 Star Tribune