The Evansville EPA has issued an Ozone Alert for Tuesday and Wednesday.
The combination of heat, bright sun, and little or no wind can cause ozone levels to reach or exceed unhealthy levels for sensitive people.
The agency warns people with heart or lung disease, children, and older adults to reduce prolonged or heavy exertion outdoors, especially between noon and 7 p.m. when ozone levels are highest.
Exposure to high levels of ozone can cause lung and throat irritation, shortness of breath, and aggravate respiratory diseases such as asthma, emphysema, and bronchitis.
The EPA urges residents to conserve electricity, use public transit or limit driving, and postpone refueling vehicles until the evening.
Outdoor cooking is permitted, but officials suggest putting off grilling until after 7 p.m.
The agency also recommends using electric or manually-operated lawn equipment, and limit the use of cleaning fluids, paint thinners, or other materials containing volatile organic compounds during the alert.