Short answer: Nope, don’t eat snow. Contrary to popular dad joke, it’s not only the yellow stuff you have to worry about.
Last winter, a team of Canadian (surprise) scientists determined that snow in urban areas can absorb toxic and carcinogenic pollutants from vehicle exhaust. The McGill University researchers discovered even the clean-looking “white stuff” can absorb significant amounts of airborn pollutants after only an hour.
The scientists ran an experiment, putting snow and exhaust fumes in a cold, sealed chamber to see how they interacted. They found that in only an hour, the snow had removed significant amounts of pollutant particles–such as benzene, toluene, ethylbenzene and xylenes–from the air. Dr. Parisa Ariya, a professor of chemistry and atmospheric sciences at McGill who led the research, says the interaction of pollutants and freezing temperatures could even cause the release of new compounds. (You can peruse their findings in depth here.)
“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,” Ariya told the Huffington Post. That being said, she noted, “I do not wish to be alarmist.”
Unsurprisingly, the contents of exhaust fumes can augment your cancer risk. In their paper the researchers noted that urban exposure to vehicle fumes (think: what you breathe walking around Washington) can drive up to 70 percent of “excess lifetime cancer incidences.”
While we wouldn’t recommend augmenting that exposure by snacking on old carcinogen-packed snow, based on this research, eating the very freshly fallen flakes might be fine. That’s good news, because snow-bourbon cocktails are a thing.