1.   And every one of them, he tells audiences, will help forestall an approaching crisis of dirty air and undrinkable water.

2.   And dirty air spreads beyond big cities.

3.   A dirty air filter restricts the air flow from the furnace and can seriously damage the furnace and blower parts.

4.   But environmentalists say it is chiefly responsible for hundreds of deaths from dirty air every year.

5.   But it seems clear that the hazards associated with dirty air are greater than originally supposed.

6.   But it also can make it more dangerous, because it can cause what we call dirty air.

7.   But other cities, because of stricter federal guidelines this year, may join Atlanta on the dirty air list.

8.   But they warn that the dirty air from Asia could increase with rapid industrial growth in the region.

9.   Dirty air is disturbed and can cause problems to the cars caught up in it.

10.   GRTA is the superagency created by the General Assembly last year to ease traffic congestion and implement transportation plans to clean up the dirty air.