You know the phrase "pure as driven snow?"

Yeah, it's entirely bunk.

A timely warning to residents of Mid-Atlantic cities about to get dumped with potentially record-breaking quantities of the white stuff was published in the latest issue of "Environmental Science: Processes & Impacts": snow in urban areas soaks up toxic pollutants in the air, including cancer-causing chemicals like benzene.

"As a mother who is an atmospheric physical chemist, I definitely do not suggest my young kids to eat snow in urban areas in general," Parisa Ariya, professor of chemistry and atmospheric sciences at Canada's McGill University who led the research, 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 the snow acted like a sponge, efficiently removing chemicals like benzene, toulene, xylenes and others 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 toulene, 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.