"If you think you might encounter tear gas you can soak a bandana or paper towel in lemon juice or cider vinegar and store it in a plastic baggie. You can breathe through the acidified cloth for several minutes, which should give you sufficient time to get upwind or reach higher ground."

"Goggles are a great thing to have. You can use tight-fitting swim goggles if chemical safety goggles aren't available."