Yes, behavior of all trees affected not only by SO2 gas, but also by acid rain, and lack of sunshine due to persistent plume. None of my avocados are flowering or fruiting. Will be quite a while, many months, before they start behaving normally again. I have an Ota, but is still a small tree. Don't know if its flowering is really that much later. If there are other people with avocado trees in your neighborhood and pollinators, then that should be sufficient.
BTW, Ota is a very nice tasting, very lard cannoball shaped avocado. You can sometimes see them being sold at Hilo farmers market.