A former Marine I know has been living in a six-unit apartment building in Van Nuys, in L.A.’s San Fernando Valley, for about four years. The rent is reasonable, the neighborhood is diverse, and the landlord is helpful. But this man has a problem, which is why he just called me. His next-door neighbor smokes.

The neighbor smokes everywhere: in his own unit, in the driveway, in front of both the former Marine’s and his own doors. The smoke is getting into my acquaintance’s unit. This is not good. He has asthma and a heart condition. When the former Marine was a child, he lived with his grandmother, whose heavy smoking turned her apartment walls brownish-yellow and made him especially vulnerable to tobacco smoke. But he can’t afford to move.

To make things more complicated, the building my acquaintance lives in is regulated by a rent-control law. This law, designed to protect tenants from egregious rent increases and potential eviction, does not permit the landlord to change the conditions of tenancy except for minimal rent increases each year. Even if the landlord wanted to do something, he couldn’t require the former Marine’s neighbor to stop smoking on the property.

At Smokefree Air For Everyone, a Los Angeles-based nonprofit I direct, we get calls from people dealing with similar problems at least once a day. S.A.F.E. has been funded for 15 years by the California Department of Public Health’s Tobacco Control Program to disseminate information about the problem of drifting tobacco smoke in residential buildings, and we’ve surveyed thousands of people who live in apartments and condos. Although the percentage of California adults who smoke is now less than 12 percent, our surveys have found that more than one in three nonsmokers who rent in L.A. County are still exposed to secondhand tobacco smoke.

This is both a local problem and a national issue. According to the Centers for Disease Control and Prevention, about 80 million (one in four) Americans live in multi-unit housing, and more than one in three renters—the same percentage as we found in our L.A. County surveys—are exposed to secondhand smoke. Secondhand smoke kills more than 400 infants and 41,000 adult non-smokers every year. Infants exposed to secondhand smoke have a higher risk of Sudden Infant Death Syndrome, and children are more susceptible to respiratory infections, ear infections, and asthma attacks. In adults, secondhand smoke can cause heart disease, stroke, and all kinds of cancers.

An air quality study in Los Angeles County in 2011 showed that tobacco smoke particles move from unit to unit through cracks in fixtures, electrical outlets, pipes, vents, and baseboards, as well as through shared ventilation systems and windows. Environmental scientist Neil Klepeis, who conducted the study, believes that as much as 30 to 50 percent of the air in a residential building may come from other units, regardless of whether the buildings are new or old. “Tobacco smoke particles in units of non-smokers can reach significant levels equal to and exceeding those of a smoky bar or casino,” he says.

Even so, most apartment renters don’t complain about their exposure to tobacco smoke. Some don’t want to start a war with their neighbors; some believe, erroneously, that there is a legal right to smoke; and some simply believe that complaining won’t help, which is frequently true. Many landlords and property management companies, even in cities without rent control, believe there is nothing they can do about a tenant who smokes. They may not understand the public health implications of their residents being forced to breathe their neighbors’ toxic tobacco fumes. Or they don’t want to be bothered with enforcing a no-smoking rule or spending money to evict a tenant for smoking. In the worst cases, we’ve seen landlords threaten to evict tenants who complain about a neighbor’s tobacco smoke in lieu of addressing the problem.

But even landlords who take legal action against tenants whose smoking is seriously affecting other tenants, on the grounds that they are creating a nuisance, may find themselves dealing with judges who are not knowledgeable about the hazards of exposure.

Condominium owners are not exempt from the problem, either. They are more likely to complain than renters, but condo boards rarely take action to help. S.A.F.E. advises people not to purchase a condo unless there is some kind of law or regulation in place that protects the residents of the building from all kinds of smoke, including smoke from cigars, hookahs, electronic cigarettes, and marijuana.

Fortunately, public housing authorities, national and state institutions, and some housing corporations around the country have begun to look at the problem. The U.S. Department of Housing and Urban Development and the CDC both recently released position papers stating that all multi-unit housing should be smoke-free.

Although they remain in the minority, some landlords, apartment corporations, and condominium boards are beginning to recognize the financial benefits of no-smoking policies. It is a lot less expensive to prepare a unit for the next resident if the previous resident didn’t smoke in it. There is less danger of fire. We hear from realtors that prospective buyers or renters don’t even want to look at units in buildings with lobbies and halls that smell of smoke. In addition, in California and some western states, an insurance group will provide a 10-percent discount for insurance for multi-unit residential buildings that have established no-smoking policies.

Approximately 40 California cities and counties have passed ordinances regulating secondhand smoke in apartments and even in condominiums. Some of the ordinances include banning the use of electronic cigarettes, and some include the smoking of marijuana. On September 15, the city of Manhattan Beach held a first reading of a housing ordinance that will require no smoking in all apartments and condos by May 2017; they used an ordinance recently adopted by Culver City as a model. Santa Monica, a city with rent control, recently passed an ordinance requiring new vacancies in apartments and condos to become non-smoking, and requiring landlords and condo boards to inform prospective residents about units that are still being smoked in. However, there are no laws regulating smoking in multi-unit residential buildings in the city of Los Angeles.

At the state level, change is happening as well. The California EPA’s Office of Environmental Health Hazards Assessment has designated marijuana smoke as a human carcinogen. 1-800-NO-BUTTS provides help in several languages over the phone for people trying to quit smoking. The more laws and restrictions that have been put in place to limit where people can smoke, the more the rate of smoking has dropped.

The CDC is providing funding for organizations throughout the country to spread the word about the financial and public health benefits of smoke-free multi-unit housing. In Los Angeles, the CDC has funded UCLA’s Center for Health Policy Research to work with apartment associations, community leaders, and policy makers to help people to live without worry of smoke exposure.

Perhaps the ex-Marine who has been suffering from secondhand smoke may eventually be able to breathe clean air.