In the early 1980s, the surgeon general alerted the public to the deadly effects of secondhand smoke. Tobacco smoke contains the addictive nicotine and a deadly mix of more than 7,000 other chemicals. Hundreds of them are toxic, and about 70 are known to cause cancer. What’s more, findings reveal that even though African Americans smoke fewer cigarettes than many other population groups, we are more exposed to secondhand smoke than other ethnic groups.

According to Brian King, PhD, an epidemiologist at the Centers for Disease Control and Prevention, the issue is complex. Studies show that black nonsmokers tend to have higher levels of cotinine in the blood—a biological sign that they’ve been exposed to secondhand smoke—when compared with nonsmokers of other ethnic groups. “The reasons for this difference are not known,” King says. “But some evidence suggests that slower metabolism or clearance of cotinine might result in African Americans having higher levels [of this nicotine byproduct] for a given amount of exposure.”

Typically, too, socioeconomic factors also play a role. Statistics show that more low-income people smoke, may not be as receptive to anti-smoking messages and might not fully understand the hazards of secondhand smoke exposure. “It is possible that these same factors could be partially contributing to the higher prevalence of secondhand smoke exposure observed in the black community,” King suggests.

And although the relationship between advertising and secondhand smoke exposure hasn’t been extensively studied, we do know that tobacco companies still throw millions of dollars into advertising squarely aimed at minorities. Remember the promotional push on menthol cigarettes? These campaigns used urban culture and language to promote menthols, even passing out samples at tobacco-sponsored, hip-hop bar nights, King recalls.

In addition, despite state and local laws to protect nonsmokers from secondhand smoke, “currently only 26 states and the District of Columbia have comprehensive smoke-free laws prohibiting smoking in all indoor areas of workplaces, restaurants and bars,” King says. Although the legislation has helped, many minorities live in locations where these laws aren’t implemented. In fact, half of the U.S. population lives in areas where nonsmokers aren’t protected in public places.

And as more public spaces go smoke-free, private settings are taking the heat. In an interesting turnabout, now homes and vehicles have become larger sources of overall secondhand smoke exposure, King observes.

To clear the haze and eliminate smoking in private settings, the public must get educated about the need to voluntarily adopt smoke-free rules behind closed doors. This would benefit everyone, King says, including the black community.