1.   But if you think polluted air is affecting your health, consult your doctor first.

2.   Our polluted air is a clear demonstration of the need for tougher environmental laws.

3.   Residents of the two cities breathe the same polluted air.

4.   What causes the acid rain that forms from water passing through polluted air?

5.   The pollution is worst during winter, when thermal inversions trap the warmer polluted air above the city.

6.   Proponents of the scheme believe the fans would form artificial tornadoes of polluted air, which would be propelled up through the thermal inversion cap.

7.   After eight hours on a job, they were back on the streets, dodging sports cars, fleeing ill-tempered dogs, breathing polluted air.

8.   Air levels in the usually clear Bitterroot Valley have reached hazardous levels, prompting health officials to urge county school leaders to consider school closings if polluted air persists.

9.   But how does polluted air collect on top?