The Colorado Emissions Test

I spent about an hour at one of Colorado's emissions testing facilities recently. This no doubt is one person's attempt at eradicating the brown cloud that occasionally hangs over the city of Denver. I wonder if it really works. Consider this:

• I spent about half an hour in line, with motor running (I would advance a few feet every so often), along with a steady stream of 25 or so other cars waiting in line with me.
• The test itself (again, with motor running) took another 30 minutes or so.
• With nothing better to do than watch the various monitors scattered about the facility, I noticed that there were frequent delays because the "ambient" air was often above "acceptable" levels. Do you think that may have had something to do with all of those cars at the facility, engines idling away?

Perhaps there may be a more efficient way to reduce Denver's air pollution. Maybe closing the emissions testing facilities would help?