I know most of you do not have this problem, but I will entertain you. My tractors are kept inside my work area and in the winter this can be an issue. The problem is that upon start up, a cold engine dumps some pretty obnoxious fumes. I find it is only start up, after I have run outside for a while I do not have to use it for re-entry. So my solution is to temporarily put a filter on the exhaust to catch 80% of the worste. My filter is 4 or 5 socks inside of one another with a rubber band. When not in use I keep it in a plastic bag. It actually works pretty good.