Ethics in Medicine

More Air Pollution Data: The Tiny Particles

Kristen Sparrow • February 20, 2012

Just a quick post and link to yet another article on air pollution. Please click on the title to read the whole article. Is it really time to defund public transportation and stop investment in high speed rail?? Really?? More on my practice here.

Scientists Find New Dangers in Tiny but Pervasive Particles in Air Pollution

Fine atmospheric particles — smaller than one-thirtieth of the diameter of a human hair — were identified more than 20 years ago as the most lethal of the widely dispersed air pollutants in the United States. Linked to both heart and lung disease, they kill an estimated 50,000 Americans each year. But more recently, scientists have been puzzled to learn that a subset of these particles, called secondary organic aerosols, has a greater total mass, and is thus more dangerous, than previously understood…

“If the authors’ analysis is correct, the public is now facing a false sense of security in knowing whether the air they breathe is indeed safe,” said Bill Becker, of the National Association of Clean Air Agencies…

Paul Shepson, a professor of analytical and atmospheric chemistry at Purdue University and one of the reviewers of the Irvine paper, called it “highly significant in scientific terms,” adding that current models of fine particulates “grossly underpredict” their density, “sometimes by as much as a factor of 10…”

The Irvine study of the formation of secondary compounds in the atmosphere, which will be published in the Proceedings of the National Academy of Science, upends previous assumptions about the fate of the byproducts of the pollution from internal-combustion engines. These gaseous byproducts were thought to incorporate themselves into tiny airborne drops of liquid that would then dissipate quickly as the drops evaporated.

The new study finds instead that they attach themselves more tightly to airborne organic particles, creating tiny tar balls that evaporate more slowly and persist longer than anyone had thought. E.P.A. models built on these assumptions now appear to understate the total amount of fine particles, according to Barbara J. Finlayson-Pitts, a professor at Irvine and one of the study’s authors.