I hate noise pollution too, but out of curiosity if you live in a place where winter has the properties that makes sound travel further, doesn't it also necessarily have the properties that make it a bad idea to leave your windows open?
Had the same thought but then thought that perhaps a smaller window upstairs opened mid-day would help airflow without affecting heat so much
How much does temperature affect sound distance? How about humidity?
When it gets cold, the leaves fall off of deciduous plants.
Is there some kind of air density factor too?
Upper floor apartments can sometimes get quite toasty, even with the heat turned off. There was a recent HN discussion about this but I wasn't able to find it.