Updated: August 20, 2013 4:54PM
The Illinois Environmental Protection Agency has extended its air quality alert through Wednesday.
The agency “action day” alert, effective until midnight Wednesday, warns that ozone levels could pose a health risk to active children, older adults and people with respiratory disorders.
The alert was issued about 4 a.m. Tuesday and is in effect for Cook, McHenry, Lake, Kane, DuPage, Kendall, Grundy and Will counties, according to the National Weather Service.
An “action day” alert is issued when air quality monitors and weather conditions indicate that ozone or fine particulate matter levels are likely to be unsafe for “sensitive groups,” according to the EPA. Alerts can be extended for additional days if conditions do not improve.
Sensitive individuals are cautioned to limit their outdoor activities Tuesday and take any precautions recommended by their doctors, the EPA said.
Area residents and businesses are also asked to reduce their air pollution by cutting back on energy use, taking public transit and using environmentally-friendly cleaning products.
This is the first air pollution action alert issued for the Chicago area this year.