Air Quality Ten Greenest Cities , 8:55pm, 03/15/2009

1. Portland, OR, 34, 12. Very clean air!

2. San Francisco, CA, 26, 19. Good. 

3. Boston, MA, 12, 63, Moderate Risk. 

4. Oakland, CA, 26,19. Good. 

5. Eugene, OR, 5.

6. Cambridge, MA, Ozone Good, Moderate PM2.5.

7. Berkeley, CA, Good, Good. 

8. Seattle, WA, 32, 10. Very Good!

9. Chicago, IL, 38, 98, very Bad!

10. Austin, TX, 29, 43.