<HTML>This table shows the non-attainment areas in term of several priority air pollutants.  The EPA website <A HREF="www.epa.gov">www.epa.gov</A> has a lot of information on every kind of environmental issue.  However you pretty much have to know what you are looking for.  The primary reason Houston is non attainment is ozone.  I don't know what that guy is trying to prove, but if he is showing that air quality is getting better, that is an argument for regulation, not against it, give that continuing regulation is what has kept the pollution down.  BTW Air Pollution is outside my area of expertise, I deal with Superfund and Hazardous Waste.  Air is too complicated for me, given that it is a compressible fluid and you have to take into consideration weather :-) http://www.epa.gov/airs/nonattn.html</HTML>