Growing up in Virginia I always heard people say that snowstorms were good because they “cleaned the air.” As a child it sounded logical to me, but as I grew older I wondered if this was really true. Well it is true (to an extent). Snowflakes form on small dust particles and as they fall from the clouds, pollution can adhere to the snowflake. So, it in fact does clean the air. But given the considerable amount of air pollution in large cities, it would be impossible for snowfall to really make a significant difference.
Now the pollution caused by the traffic, caused by the snowfall, well that’s another issue!