Lung cancer is the single largest cause of cancer mortality, accounting for about 19% of all cancer deaths. Lung cancer is almost entirely driven by chemical carcinogens, notably PAH, found in smoke, which accumulate over time in the lungs of smokers. The experiment will visualise the removal of a fluorescent PAH carcinogen(benzo(a)pyrene) from epithelial cells by treatment with two perfluorocarbon liquids, under UV fluorescent microscopy.