Related by context. Frequent words. (Click for all words.) 64 Secondhand smoke 64 cigarette smoke 58 Passive smoking 57 Inhaling 57 Cigarette smoking 56 Prolonged exposure 55 Particulate matter 53 polycyclic aromatic hydrocarbons PAHs 53 Sulfur dioxide 51 Oxidative stress 51 Carbon monoxide 50 carcinogens 50 harmful toxins 50 polycyclic aromatic hydrocarbons 50 aggravate asthma 50 nitrosamines 50 Obstructive sleep apnea 49 ultrafine particles 49 secondhand smoke 49 aldehydes 48 Toxic chemicals 48 secondhand tobacco 48 Nitric oxide 48 Carbon dioxide 48 suspected carcinogen 48 Saturated fat 48 passive smoking 48 mucous membrane 48 pet dander 47 carcinogenic chemicals 47 nitrous oxides 47 sun ultraviolet rays 47 incomplete combustion 47 Nitrous oxide 47 clog arteries 47 asthma bronchitis 47 Volcanic ash 47 Hydrogen peroxide 47 VOCs 46 bronchial tubes 46 toxins 46 diesel exhaust 46 Periodontal disease 46 Smokeless tobacco 46 Tooth decay 46 diesel fumes 46 Baking soda 46 Sleep deprivation 46 hormone cortisol 46 soot particles 46 sulfur hexafluoride 46 methyl mercury 46 sebaceous glands 46 acetaldehyde 46 Lung cancer 46 organic acids 45 chemical vapors 45 methylene chloride 45 urushiol 45 nicotine 45 estrogen hormone 45 harmful contaminants 45 Cirrhosis 45 Dioxins 45 Nicotine 45 Soot 45 metabolizes 45 toxicants 45 respiratory tract 45 toxic chemicals 45 hormone disrupting 45 Acrylamide 45 cotinine 44 nitrogen oxides NOx 44 oxidizes 44 aerosol spray 44 colon breast 44 coughing wheezing 44 Trans fat 44 nonsmokers 44 water vapor 44 Poison ivy 44 Cigarette butts 44 Chewing gum 44 neurotoxic 44 harmful chemicals 44 particulates 44 inhale 44 unpleasant odor 43 Sudden cardiac arrest 43 Quitting smoking 43 fine particulates 43 catechins 43 endocrine disruptors 43 chemical compounds 43 PBDE 43 thick mucus 43 sulfur dioxide 43 exhaust fumes 43 cigarettes smoked 43 carcinogenic