tobacco smoke carcinogens and lung cancer The harmful chemicals in smoking directly damage cells, causing DNA mutations that increase risk. Over time, these damaged cells grow abnormally, leading to tumor formation in the lungs. Quitting smoking Lung Carcinogenesis by Tobacco Smoke

One benefit of restricting tobacco sales to those 21 and older is that it makes it more difficult for younger high school students to rely on friends who have turned 18 to purchase cigarettes for them, said Silver

George Koob, director of the U.S

A fan helps to keep mosquitoes away because: (a) mosquitoes are unskilled pilots in high winds (b) a fan helps to disperse the carbon dioxide, body odours and other chemical cues that allow mosquitoes to detect your presence and determine your exact location While the really desperate or hungry mosquitoes will still try (sometimes successfully) to land on your alluring body in spite of the gale force winds, a fan running on its medium or high speed setting definitely helps to hold them off

Mecklenburg R E, Greenspan D, Kleinman D V, et al