I think I mentioned somewhere before that a mask that traps particles µm and smaller would help. That was a typo. I meant to say nanometers rather than µm. Some of these compounds were very small, and could really only be effectively blocked by a full face respirator (half-mask air-purifying respirators will not cut it, as they leave the eyes open). If I had to guess at other methods of avoiding these chemicals, I would say avoid living anywhere near moderate or large sized cities. This is just me hypothesizing, but I don't know why someone would spend millions of dollars developing chemical compounds so they could spray them over nearly unpopulated areas.