Air Quality, 10 Greenest Cities 2008, 10:45pm, 03/11/2009

1. Portland, OR, 30, 27, Good.

2. San Francisco, CA, 24, 27.

3. Boston, MA, 10, 54. Moderate Health Risk. 

4. Oakland, CA, 24, 27.

5. Eugene, OR, 28. 

6. Cambridge, MA, Moderate Particulate Matter.

7. Berkeley, CA, Good. 

8. Seattle, WA, 25, 15.

9. Chicago, IL, 28, 33.

10. Austin, TX, 23, 8. 

http://www.popsci.com/environment/article/2008-02/americas-50-greenest-cities?page=1