Originally Posted by Fabrik8

Snow is just like acid rain. Pure condensate picks up other substances from the atmosphere as it condenses and as it travels downward. So whatever is causing the plastic smell is some constituent chemical compound that is probably also in plastic. I don't think the snow contains any polymeric compounds, no.

The black donuts in that video look like light and shadows from bubbles. It's a optical illusion, you can tell when the black donuts pop and disappear. It wouldn't surprise me at all that sleet would contain carbon and soot from the atmosphere though. Especially if you collected some from China.

The thing is, if you put snow in a mass spec, you would see all of the elements that it picked up. You wouldn't see plastic if there was plastic in it, you'd see all of the chemical signatures that make up the plastic.