Last Michigander my brother and I were riding on a trail and something that had never happened to us happened. We were simultaneously overcome by pollen induced asthma attacks. We made it in that day, but going about 5mph and getting passed by 65 year old fat women. Being as I have a bunch of respirators, we decided this won't be happening again, because we'll carry one for each of us this year. But the problem is, I don't know how good they'll have to be. Do any of you scientist types know what it takes to filter out pollen?
I don't know how big the particles are, so I don't know what type of filtration is needed. I don't trust paper dust masks, but if they could filter the bulk, that seems it would work. Hepa filters on a half face would be the next step up, followed by organics with hepas on top on half faces. I'm sure we won't need PAPR's.