Well I haven't found anything directly from the EPA yet about that, all I can find are a few omg2strokesarekillingtheplanet websites...but I will agree they do pollute more than a 4-stroke. But considering I can go 120-130mi on one gallon of gas on the bike compared to 21mi in my car, I think that is still something to be considered.
Anyway, I did stumble on this article Green Earth Technologies’ New Petroleum-Free, No Smoke, 2-Cycle Green Engine Oil Now Available
about a company making bio-based 2-stroke oils that can reduce emissions. The companies website is here: Green Earth Technologies’ New Petroleum-Free, No Smoke, 2-Cycle Green Engine Oil Now Available
I think I might see if I can get ahold of some and see how it works out.