When an air quality alert goes off, the allergy medicine in your cabinet is probably the wrong one, and not for the reason you'd guess. Wildfire smoke does trigger a real histamine response, so the right antihistamine helps. But taking one and going outside anyway creates a far more dangerous problem, one that has everything to do with PM2.5 and nothing to do with how you feel. Here's what actually protects your lungs during a smoke event.