Smoking is a widely acknowledged danger to human health. Tobacco smoke causes or exacerbates conditions including asthma, respiratory infections, and cancer. According to the Center for Disease Control (CDC), smoking leads to 440,000 deaths a year in the United States. However, smoking is less frequently viewed in terms of environmental health. In its tally, the CDC includes nearly 50,000 deaths from second-hand smoke, a risk associated with proximity to a smoker and a form of air pollution.
Environmental tobacco smoke contains cancer-causing compounds that the U.S. government regulates as hazardous air pollutants. Further, environmental tobacco smoke has a very high content of fine particulate matter or PM2.5, the EPI indicator for air pollution. A cigarette in the mouth of a passerby may represent more than just an occasion to hold one’s breath. It may be a pollutant potent enough to rival a passing car. A 2004 study conducted by researchers at Italy’s National Cancer Institute compared the output of three lit cigarettes and a diesel engine.1 After 30 minutes of continuous exposure in a controlled garage, the scientists found that the cigarettes released ten times the particulate matter of the engine.
Environmental tobacco smoke poses a significant health risk after long-term exposure in enclosed spaces, though it still ranks low on gross causes of air pollution, a list topped by transportation, industrial and agricultural emissions, power generation and residential heating and cooking. Yet while smoking is not a leading human cause of air pollution, air pollution has now been deemed a leading environmental cause of cancer deaths. The International Agency for Research on Cancer, a branch of the World Health Organization, announced this October that air pollution causes lung cancer and increases the risk for bladder cancer.2 As air pollution, like tobacco smoke, is found to be carcinogenic, the line between human and environmental health blurs. Public health strategists, air quality experts, and policymakers alike have every incentive to make clean air a priority.
1 Invernizzi, G., Ruprecht, A., Mazza, R., et al. (2004) Particulate matter from tobacco versus diesel car exhaust: an educational perspective. Tobacco Control 13: 219-221.
2 Loomis, D., Grosse, Y., Lauby-Secretan, B., et al. (2013) The carcinogenicity of outdoor air pollution. The Lancet Oncology 14:1262-1263.