The Washington Post

Don’t eat that snow!


In urban areas, the seemingly pure white stuff soaks up pollutants even as it falls.

You know the phrase “pure as driven snow”? Yeah, it’s entirely bunk. As much of the East Coast dug out from record-breaking quantities of the white stuff, the latest issue of the journal Environmen­tal Science: Processes & Impacts published a study showing that snow in urban areas soaks up toxic pollutants in the air, including cancer-causing chemicals such as benzene.

“As a mother who is an atmospheri­c physical chemist, I definitely do not suggest my young kids eat snow in urban areas in general,” Parisa Ariya, a professor of chemistry and atmospheri­c sciences at Canada’s McGill University in Montreal, told the Huffington Post.

Ariya’s research wasn’t primarily focused on snow as a gastronomi­c delicacy. Instead, she and her colleagues were looking at how snow and cold interact with particles in gasoline exhaust.

They found that snow acted like a sponge, efficientl­y removing benzene, toluene, xylenes and other chemicals from the air.

Of course, all of those chemicals then end up in the snow, where they make for a very unsavory snack. Benzene, which is present in gasoline, crude oil and cigarette smoke, interferes with cell functions and can cause anemia, leukemia and other problems, according to the World Health Organizati­on. The Environmen­tal Protection Agency says that toluene, a gasoline additive, can damage the central nervous system, while xylenes are associated with neurologic­al problems, breathing difficulti­es and kidney failure, among other concerns.

“These findings demonstrat­e that the interactio­n of gasoline internal combustion exhaust with snow and the effect of cold temperatur­e have a potential to influence human health and environmen­tal effects associated with exposure to exhaust-derived air pollution,” the study said.

It also warned that environmen­tal researcher­s should take into account that the presence of snow and cold might alter measures of the amount of pollutants in the air.

If you really have to eat snow — though we’re having trouble imagining a situation in which this might become a concern — John Pomeroy, who studies water resources and climate change at the University of Saskatchew­an, suggests waiting a few hours after it begins to fall. Snow’s “scrubbing brush” effect on the atmosphere means that the air — and the snowflakes themselves — get cleaner as a snowstorm goes on, Pomeroy told NPR’s “The Salt” last winter.

Most of the researcher­s “The Salt” spoke with said that toxin levels in snow are low enough that they would consider eating it. And, as one should for a fine culinary treat, these true snow connoisseu­rs knew how to savor it.

“It is well known amongst snow chemists that fresh Arctic snow goes very well with 15-year-old single malt whiskey,” Pomeroy said.

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 ?? ISTOCKPHOT­O ?? Urban snowflakes soak up pollutants as they fall.
ISTOCKPHOT­O Urban snowflakes soak up pollutants as they fall.

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