This is an archived article that was published on sltrib.com in 2013, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

During a casual conversation about the inversion and related breathing problems, someone asked, "Have you checked your furnace filter lately?" I replied that I had just changed it in January.

"Check it again," he said. "I just changed mine, and it was filthy."

Well, I did, and just as predicted, it was dirty. Just because a person stays indoors doesn't mean they aren't breathing polluted air.

I applaud those who are pursuing a reduction of air pollution.

Harry W. Patrick

Salt Lake City,