People wearing contact lenses may experience increased eye irritation and damage due to chemicals being trapped under the lenses. If your choice is between oil-based or nothing, we advocate using the sunscreen. Getting pepper sprayed on top of a sunburn is not fun. We also recommend minimizing skin exposure by covering up as much as possible. This can also protect you from the sun, as can a big hat.
Gas masks provide the best facial protection, if properly fitted and sealed.
Panicking increases the irritation. Breathe slowly and remember it is only temporary. If you see it coming or get a warning, put on protective gear, if able, try to move away or get upwind. Blow your nose, rinse your mouth, cough and spit. Try not to swallow.