Whether or not you agree with the liberal opinion on the effect of greenhouse gases on our ecology, I think you can agree that the exhaust from fossil fuels is dangerous. I am living proof. The only members of my family with asthma were born and raised in major metropolitan areas. All members born and raised in metro areas have asthma, none born and raised in suburban or rural areas have it. Aparently, my family isn't an anomaly:
Study Links Air Pollution and Asthma
Researchers Link Childhood Asthma to Exposure to Traffic-related Pollution
Researchers Link Childhood Asthma to Exposure to Traffic-related Pollution(again)
Link Strengthened between Air Pollution, Asthma