There are two things that attract mosquitoes to their prey: heat and carbon dioxide. When the pests sense a warm body breathing out CO2, they know they've found a snack. Instead of slathering yourself with chemical bug repellants, try this simple trick instead: Turn on a fan. When you have a tabletop or ceiling fan blowing air, it cools your body temperature and spreads the CO2 emissions around, making it harder for the mosquitoes to detect you.