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.
People recovering from substance abuse are twice as likely to relapse within three years if they are a smoker.
Weinberger, Andrea H., et al. “Cigarette Smoking Is Associated With Increased Risk of Substance Use Disorder Relapse: A Nationally Representative, Prospective Longitudinal Investigation.” The Journal of Clinical Psychiatry, Physicians Postgraduate Press, Inc., 22 Feb. 2017.