I remember as a kid in the 60’s and 70’s my grandfather would berate us for eating snow. “You’re gonna pick up all that radioactivity from the atmosphere you know,” he’d shout into the back yard. His concern was the fallout from nuclear testing, a concern of his generation.
I stumbled across a post at Julie’s Health Club that got me thinking about my grandfather, and my own kids. So is snow safe for kids? Helen Suh Macintosh, a professor of environmental health at Harvard, put together a nice summary of the snow issue last year. She notes:
“It turns out that snow is a fairly efficient pollution collector when it is in the air. Snow is formed by water vapor that moves in clouds in cold air. As the water vapor moves in the cold air, it can stick to a tiny piece of dust and then have other water molecules attach to it, forming a crystal. Once formed, the crystal can continue to grow and can stay in the air for hours before it falls to the ground. It is during this time that the snow crystal can collect or “scavenge” pollutants that are present in the air.” This, of course, is a bigger issue in urban areas than in rural areas.
Macintosh goes on to suggest that white snow is probably a safe bet in small quantities. And for the incredulous child, the impurity of snow can be demonstrated by melting some in a glass and simply looking at it. After all, seeing is believing.