A new study suggests that traffic pollution may also harm babies before they are born. Moms in California's polluted San Joaquin Valley who breathed traffic pollution early in their pregnancies were more likely to have babies with birth defects compared to moms who breathed less traffic pollution.

Cities are converting their fleet of buses over to greener cleaner burning natural gas buses and more trucks are being required to wear particle diapers. So urban air is slowing improving. In the meantime, a few tips to duck that diesel plume.

We've seen past Republican and Democratic presidents alike support environmental regulations without the alleged "the sky is falling" scenario come true.

Commuters probably weren't expecting this on their way to work in the morning. But beginning July 12th, the Sierra Club took over all of the ad space ...