No Reason to Fear Dust

Published March 24, 2005

Your article by Jim Carlton (“Study Reveals Toxic Chemicals in Household Dust,” March 23) was extremely disappointing in its lack of specificity.

Carlton reported on a very small study that found in household dust chemicals deemed toxic to rodents and perhaps man. He described the concentrations as traces not believed to impact human health.

I believe it is about time the Wall Street Journal and other media outlets begin defining the actual concentrations represented by the word “trace,” because the public has no idea what that word means and thus is frightened by it.

With 50 years of experience as an environmental scientist, I was first limited to laboratory tests that could measure at the parts per million level. Over time, my equipment improved three orders of magnitude to parts per billion. Today, I can conventionally measure in parts per trillion, which is approximately equal to a single second within 32,000 years–yes, 32 thousand years!

Some laboratories can now go three orders of magnitude smaller yet, to parts per quadrillion. This is approximately the ratio of a single hair on a human head to all the hair on the heads of the entire Earth’s population, assuming 150,000 hairs on a healthy head multiplied by the current Earth population of 6.3 billion.

Should we be concerned with such minute concentrations? Certainly not. Soon we will be able to measure single molecules and will likely find something of everything in everything else.

It’s time your readers understand what you and others actually mean by the term “trace.” The chemophobia that tends to grip society as a result of intentional fear-mongering may then begin to subside.

Dr. Jay Lehr
Ostrander, OH

Dr. Jay Lehr ([email protected]) is the editor of several science reference books, including McGraw-Hill’s Standard Handbook of Environmental Science, Health, and Technology, and Science Director of The Heartland Institute, a national nonprofit research organization based in Chicago.