Fewer cars on the road due to the COVID-19 pandemic has led to better air quality in many parts of the world. But state officials say its harder to tell what impact "Stay-At-Home" orders have had on air quality in Indiana overall.

Some parts of Indiana that have struggled with pollution are now meeting federal air quality standards, according to data from state and federal environmental agencies.

People who live in polluted areas are more likely to have the underlying heart and lung conditions that put them at a greater risk from COVID-19.

The U.S. Environmental Protection Agency announced Monday Terre Haute and the rest of Vigo County now meets the National Ambient Air Quality Standard for sulfur dioxide.

Nine counties in Indiana received an "F" for ozone, mostly near major cities like Chicago and by coal plants in the southwest part of the state.

The Environmental Protection Agency says the company emitted higher than normal levels of cadmium for eight days last year.

A state analysis of local wind patterns suggest that the lead released by the mill complex could be blowing north and west toward Chicago or south toward the Indiana community of Chesterton.

The report says Indianapolis and South Bend rank among the 25 worst areas in the country for short-term particles in the air.

Maryland environmental officials filed a petition Wednesday asking the EPA to crack down on 19 coal plants in Indiana, Kentucky, Ohio, Pennsylvania and West Virginia.

A lawsuit could add Indiana to the Ozone Transport Region, a group of 11 states required by the EPA to reduce smog-causing pollutants.