I also suffer from asthma, and I worry about the air that I breathe. I live across the street from a construction company that has numerous trucks and huge mobile equipment driving down the street all day. These huge trucks run on "diesel fuel," and they emit small particles from the diesel fuel in the air that contribute to cancer.
I have to keep my doors and windows closed all year long because of this. I have complained to the health department and the EPA. The company has made no changes, but I will continue to call and complain because I want to breathe clean air.