Mosquito inhibitors, also known as mosquito barriers, emit a scent which blocks a mosquito's olfactory receptors and keeps them from tracking down humans. The scent which is emitted by these devices is virtually undetectable by humans and is circulated over an area by fans and vents. Mosquito inhibitors are known to protect up to 100-square feet of area, and work best when placed on the ground near grass and foliage. The effectiveness of mosquito inhibitors depends on the humidity, the wind and the mosquito population in that area. Highly recommended mosquito inhibitor products include the Mosquito Deleto and the Mosquito Cognito by Coleman which cost between $15 and $30. Scent refills usually last about one month and cost between $12 and $20 to refill each time.