After the U.S. Surgeon General declared that no levels of secondhand smoke are considered safe in 2006, homeowners and businesses alike began cracking down on indoor tobacco use. A recent study featured in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report has revealed that the number of Americans who allow smoking in their homes has been cut in half during the past two decades; however, secondhand smoke still remains a major public health concern.

"It’s a shift in social norms," lead author of the CDC study Dr. Brian King told Reuters Health. "People no longer see smoking around non-smokers as socially acceptable behavior. We know there is no safe level of secondhand smoke. The ultimate goal is to not expose people to a known carcinogen.”

According to the American Cancer Society, 42,000 nonsmokers die each year as the result of heart disease caused by secondhand smoke. Other forms of death and disease caused by a combination of sidestream smoke, smoke from the lit end of a cigarette, pipe, or cigar, and mainstream smoke, smoke exhaled by smokers, includes 3,400 lung cancer deaths among nonsmokers, between 150,000 and 300,000 lower respiratory tract infections in children under 18 months, and a worsening of asthmatic symptoms in up to one million children suffering from asthma.

Researchers from the CDC used the Tobacco Use Supplement to the Current Population Survey, which analyzes national and state data surrounding tobacco use and smoking-related issues such as home smoking rules. During telephone and at-home interviews, each member of the household was asked "Which statement best describes the rules about smoking inside your home?" Responses included: "No one is allowed to smoke anywhere inside your home," "Smoking is allowed in some places or at some times inside your home," and "Smoking is permitted anywhere inside your home."

The national prevalence of smoke-free households in the U.S. has grown to 83 percent as of 2010-2011 compared to 43 percent back in 1992-1993. In American households with no adult smokers, the national prevalence of smoke-free home rules increased from 56.7 percent in between 1992 and 1993 to 91.4 percent between 2010 and 2011.

In American households with at least one adult smoker, the national prevalence of smoke-free home rules grew from 9.6 percent between 1992 and 1993 to 46.1 percent between 2010 and 2011. The research team from the CDC attributed the national increase in smoke-free households to comprehensive smoke-free laws applying to public places and workspaces as well as declines in national smoking prevalence.

Source: Babb S, Patel R, King B. Prevalence of Smokefree Home Rules — United States, 1992–1993 and 2010–2011. Morbidity and Mortality Weekly Report (MMWR). 2014.