Air quality could drop Friday in Indianapolis, nearby counties

Cars race through Turn 2 of Indianapolis Motor Speedway with the skyline of downtown Indianapolis in the backdrop during the NASCAR Nationwide Series Indiana 250 on July 27, 2013. (Chris Graythen/Getty Images)

INDIANAPOLIS (AP) — Hot weather could make it hard for some people to breathe Friday in Indiana.

An air quality action day has been posted for at least 20 counties in central and southeastern Indiana. Officials say people who are sensitive to air quality might feel it when ozone levels are high, especially the elderly and anyone with a heart condition.

The sun and high temperatures can combine to turn vehicle exhaust and factory emissions into ground-level ozone. In Indianapolis, there will be free access Friday to the city’s bike share program to get people out of their cars.

Here are the counties where ozone could be high: Marion, Bartholomew, Boone, Brown, Delaware, Hamilton, Hancock, Hendricks, Johnson, Madison, Monroe, Morgan, Shelby, Clark, Floyd, Harrison, Jackson, Jefferson, Scott and Washington.