These bug repellents actually work - if you use them correctly
Even the best products can be dangerous if used incorrectly. Here’s what the EPA recommends—and what experts say are completely ineffective.
Sprays, ultrasonic devices, wristbands, citronella candles: There’s a ton of products on the market that promise to keep away mosquitoes, ticks, and other bothersome bugs. But which products best protect against these biting and bloodsucking pests?
It’s important to protect yourself, as mosquitoes and ticks can transmit debilitating diseases like West Nile virus and Lyme disease. Yet not all repellents are created equal, and some don’t work at all. The repellent you might want to use depends on where you live, how long you’ll be outdoors, and which bugs you’re trying to repel. It also comes down to personal preferences, like fragrance strength.
Mosquitoes are attracted to the “bouquet” of scents on your skin, according to Conor McMeniman, an entomologist and infectious disease expert at Johns Hopkins University.
These are chemicals our bodies produce as they break down sugars and proteins for energy, like lactic acid and carbon dioxide, as well as those produced by bacteria on the skin. Some people smell more tantalizing to mosquitoes based on their unique cocktail of chemicals. Scientists believe that repellents disrupt mosquitoes’ and ticks’ ability to smell us.
The EPA keeps a handy list of compounds that effectively fight off disease-harboring pests, and tells you which pests each repellent keeps away. These repellents have a relatively low environmental toxicity and are safe for humans in accepted doses.
Of these, DEET was the first chemical-based repellent on the market, and some experts consider it to be the most effective against many biting insects, says Dan Markowski, technical advisor at the American Mosquito Control Association. Although repellents are sold in concentrations of up to 100 percent DEET, protection doesn’t get better after about 50 percent, says Erika Machtinger, an entomologist and chemical ecologist at Pennsylvania State University, and even low concentrations offer good protection. There is a negligible increase in how well a repellent works once its DEET concentration gets above 30 percent; the EPA recommends between 10-30 percent. The EPA also states that DEET most likely doesn’t pose a risk to the environment, at least the way we use it on ourselves.
According to the National Pesticide Information Center, while DEET stays in the soil and wastewater, it degrades quickly. Several studies have shown the concentrations of DEET found in streams and rivers are too low to do damage to aquatic wildlife. The same goes for all other products on the EPA’s list, explains Machtinger: all of them have been scientifically tested for safety for humans and wildlife.
(Excerpt from ‘These bug repellents actually work - if you use them correctly’, nationalgeographic.com, 2023)
According to the text, why is it important to use bug repellents?