Thankfully, Seattle is still a pretty clean place to live, although traffic seems to get worse all the time. Check out http://www.scorecard.org/index.tcl to see how your city rates. Hey Michael (my brother), I know the skiing is great at Alta, but Salt Lake City is ranked #37. See http://www.environmentaldefense.org/dangerousdays.cfm?subnav=aiyc_50cities for the full list of the 50 worst cities for air polution.
See http://www.environmentaldefense.org/dangerousdays.cfm?subnav=10ways what you can do to help reduce air polution.