Most mosquito foggers are propane-powered. The propane is used to heat up the chemical mixture as it is disbursed, transforming it into a very fine fog of tiny particles instead of a stream of liquid. Electric power foggers function similarly but use electricity to heat the insecticide.
The disbursed fog both kills mosquitoes on contact and typically repels any newcomers to the spraying area for 6 to 12 hours after fogging.