How bad can it be? Well, if you lived in Los Angeles, or Houston or Pittsburgh (other large metropolitan or industrial area) in the 1960's and 1970's, you'd have a good idea. http://airnow.gov/ Calif. farm town is nation's smoggiest http://news.yahoo.com/s/ap/smog_town We have a similar problem in the area where I live. Pollution travels in from the NY Metropolitan and NJ areas, and we sometimes exceed max. allowable levels of ozone and other pollutants. One can 'taste' as well as smell the foul odor.