Spatial repellents are convenient, not as reliable as topical

Spatial repellents like metofluthrin and transfluthrin work by creating a mosquito-free zone in the air, but they are not as effective as applying something directly to your skin.

These are volatile pyrethroids that evaporate from a heated mat, cartridge, or candle and spread through the air. They confuse or irritate mosquitoes at a distance, so the bugs stay away from the area. Think of them as a force field around your patio or room. Topical repellents (DEET, picaridin, oil of lemon eucalyptus) work by coating your skin so a mosquito that lands gets a whiff of something nasty and leaves before biting. That’s a much more direct and reliable mechanism.

In still air and moderate mosquito pressure, a spatial repellent can reduce bites significantly. But the moment there’s a breeze, or you’re near the edge of the treated zone, protection drops off fast. They also don’t last as long as a good topical. Most spatial products give you a few hours at best, and they can’t protect your ankles and wrists the way a dab of DEET can. If you’re sitting still in a protected corner of a deck with no wind, they’re fine. If you’re walking around, gardening, or hiking, they’re almost useless.

I’d use spatial repellents as a supplement, not a replacement. Pop one on the picnic table while you eat,