Metra says it will install pollution filters to cut the amount of diesel soot inside its outbound commuter train cars by an average 75 percent.
The Chicago Tribune reports that Metra plans to equip all rail cars with high-efficiency filters within 90 days. Metra also has begun using ultra-low-sulfur fuel to reduce diesel pollution.
The changes are in response to a Tribune report that found high levels of pollution inside the rail cars. Microscopic soot can lead to breathing and heart problems.
Diesel levels are higher on outbound trips because much of the soot is drawn into the cars while they idle at underground stations in Chicago.
The filters won't reduce exposure for people waiting inside Chicago's three downtown stations. Moions. More thare than 245,000 commuters move through those stations every weekday.