Even brief contact with secondhand smoke can cause harm.
U.S. Department of Health and Human Services. A Report of the Surgeon General: How Tobacco Smoke Causes Disease: What It Means to You. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2010.
Every day, cows release methane gas into the air. From you know where. But methane is also found somewhere else. Yesiree, in cigarette smoke.
"Smoking and Tobacco Control." U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health, National Cancer Institute. Risks Associated with Smoking Cigarettes with Low Machine-Measured Yields of Tar and Nicotine, 19 Nov. 2001. Report.