State pollution authorities issued a two-day air pollution health advisory Sunday afternoon for the Twin Cities and Rochester. Sunny skies, high temperatures and low winds caused pollution to accumulate and form ozone that was rising toward unhealthy levels, they said.
Ozone concentrations peak in the afternoon and into evening, and drop overnight. Authorities expect the health advisory to remain in effect until Monday night.
Those most sensitive to ozone are people with respiratory or cardiovascular conditions, the elderly, children and individuals who work or exercise outdoors for extended hours or with heavy exertion. High ozone levels can cause breathing difficulties, shortness of breath, breathing discomfort and coughing or sore throats.
Health officials advise sensitive individuals to postpone or reduce vigorous outdoor activity, or schedule work or exercise in the morning when ozone levels are lower.
Ozone is produced on hot, sunny days by a chemical reaction in the air between pollutants released from motor vehicles and other activities that involve fuel burning. During alerts, individuals are encouraged to postpone or reduce vehicle trips, use of gasoline-powered equipment and burning wood.