In April, May and June WFPL tested the indoor air quality of 17 homes in the Louisville area using MicroAeth monitors. MicroAeths measure for black carbon, a type of particulate matter created by incomplete combustion. In the United States, the most significant source of black carbon is from cars and trucks.
The size of the dots on the map correlates with the home's average reading. Click on the dots to learn more, and view the individual data from each testing site. To read and listen to the series, click here.