Environmental advocates predict an increase in human respiratory problems unless the government acts to lower ozone standards.
J. Drake Hamilton, an energy policy analyst for the St. Paul-based advocacy group Fresh Energy, expects the federal government will announce lower ozone standards in July.
Hamilton said that in Minnesota, some utility companies have lowered pollution emissions by converting coal burning power plants to natural gas. She said others are reviewing options including replacing older, inefficient plants.
"In Minnesota those demonstrated lower cost power sources include energy efficiency and wind power," Hamilton said. "So I think with a combination of energy efficiency and renewables like wind and hydro power and natural gas, this is something that has been big winners for Minnesota utilities."
Experts say emissions from coal burning power plants and vehicles are major contributors to ozone creation.