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Your Nose Knows: The Invisible Threat of 'Thirdhand Smoke'

Cigarette

First Posted: 08/26/11 05:16 PM ET Updated: 10/26/11 06:12 AM ET

Before this week, employees at the Indiana University Health medical center were free to step off the nonsmoking campus and light up a cigarette. Sure, co-workers and patients would probably notice the telltale odor on the smoker's clothes, skin and breath -- especially if they happened to share an elevator -- but they could do little more than plug their nose in defense.

That all changed on Monday when the medical center upgraded its policy: Employees are now prohibited from smoking during the workday. Period.

The impetus for the new rule is the recently recognized dangers of "thirdhand smoke," the gases and particles that cling to clothing, hair, furniture, walls and other surfaces long after a cigarette is stubbed out.

Dr. Richard Graffis, executive vice president and chief medical officer at Indiana University Health, describes it as "the smoke you don't see, but that your nose tells you is there."

Over his more than 40 years in the health care business, Graffis has seen a dramatic evolution -- from widespread acceptance of doctors and patients smoking inside the hospital to increasingly stringent bans -- as evidence grew of the health risks posed by both direct and indirect exposure to cigarette smoke.

"Now we've come to realize that these particles or toxins can build up [in the environment] over time," said Graffis.

Typical indoor ventilation removes about half of the particulate matter released from the tip of a cigarette, said Suzaynn Schick of the Center for Tobacco Control Research and Education at the University of California, San Francisco. The remaining sticky tar, oil and waxy compounds are left to accumulate, toxic layer upon toxic layer.

"You basically build up a giant reservoir of cancer-causing compounds on every surface," said Schick. "And it stays there."

According to a recent study led by Georg Matt of San Diego State University, nicotine will persist in a house previously occupied by smokers even if the rooms are given fresh layers of paint, new carpeting and standard cleaning.

"I get lots of stories of people with asthma who move into environments that are full of thirdhand smoke and report increased problems," Matt said.

"This is more than just a nuisance like the smell of dirty socks," added Matt, who called smokers "mobile tobacco contamination packages."

Research has suggested that the act of smoking doesn't even have to take place inside the home, hospital or other indoor space to leave a toxic deposit behind. In a study of used cars, Matt found contaminated dust on the dashboard and in the carpeting and upholstery of cars owned by smokers who refrained from lighting up inside their vehicles.

While people are less likely to be affected by these thirdhand toxins than by the more widely recognized first- and secondhand smoking, Timo Hammer of the Hohemstein Institute for Textile Innovation in Germany suggested that touching contaminated surfaces and ingesting dust can still be hazardous, especially if that exposure extends over a period of time. At particular risk are children and people with compromised heart, respiratory or immune systems.

Given their different interactions with the environment -- crawling on the floor and putting objects in their mouths -- children are typically exposed to twice as much contaminated dust as adults.

Young children are apt to suck on a parent's clothes as well. Hammer described the common scenario of a parent coming inside after a smoke break and picking up a child.

A number of thirdhand smoke's toxic components are also released by first- and secondhand smoking, including formaldehyde, benzene and arsenic. However, researchers have encountered more potent compounds in the thirdhand residue, not all of which are detectable by the human nose.

Nicotine, the main component of cigarette smoke, can react with gases such as ozone and nitrous oxide to form lung cancer-causing compounds called tobacco-specific N-nitrosamines (TSNAs). As the smoke ages, concentrations of these compounds have been found to increase.

Virander Rehan of the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center co-authored a study published earlier this year that found prenatal exposure to TSNAs and other toxins from thirdhand smoke disrupted lung development in rats.

Several previous studies, including one released this week, have made the link between cigarette smoke exposure during pregnancy and an increased risk of asthma for the child. Rehan concluded the same from his model and hopes to confirm that finding with humans.

Components of cigarette smoke, such as lead, are known to impede a child's brain development as well.

"Some of these effects that we have known for decades may be mediated through thirdhand smoke exposure," Rehan said.

"We now have reason to suspect that there are disease processes set in motion due to the carcinogens in this mixture," said Matt of San Diego State. "We know what they do to living cells and developing organ systems. Still, what exactly they do in real life and in infants that play and live and sleep in these environments will take years to find out."

In the meantime, Jonathan Winickoff of Massachusetts General Hospital for Children and Harvard Medical School and a member of the research team that originally coined the term "thirdhand smoke" in 2008, suggested taking a precautionary approach. "A lot of this stuff is not known," he said. "But the Surgeon General has said that there is no safe level of secondhand smoke, and a lot of the compounds of thirdhand smoke are the same."

Indiana University Health is just one of a growing number workplaces, restaurants and schools implementing new rules to protect public health, as well as save their pocketbooks from higher health insurance and cleanup costs. Those who smoke are not even being hired by some employers, such as Weyco, an insurance benefits company in Michigan that made headlines in 2005 over its controversial decision.

More multi-unit housing complexes are also declaring themselves 100 percent smoke-free. Earlier this month, Maine became the first state to adopt a nonsmoking policy for all its public housing buildings. Meanwhile, California lawmakers are contemplating allowing landlords to ban smoking on their properties.

Schick, who testified in support of a smoking ban for San Mateo (Calif.) County's multi-unit housing, noted another often unrecognized risk of thirdhand smoke. Even if prior tenants never smoked in a particular unit, rooms may still harbor remnants of tobacco smoke that traveled via ventilation systems, down hallways and through cracks in the walls.

To really clear the air, "you have to take out the wallboard," Schick said. "It's like cleaning up after Hurricane Katrina."

Matt offered some advice when renting an apartment, checking into a hotel room or shopping for a used car. "If you smell something, keep looking," he said. "Be careful, and trust your nose."

Hospitals should pay particular attention to the thirdhand smoke problem, said Matt, because the people who are typically the most sensitive to the health effects of tobacco smoke are often the same people who spend the most time in a hospital.

"You don't want these compounds to be around the perinatal ICU or children who have respiratory problems," he said. "Hospitals are full of people who desperately need clean air."

Graffis did note some pushback from Indiana University Health employees who smoke, but added that nonsmokers are "thrilled." He expects patients to be grateful for the new rule as well.

"We're in the business of protecting people's health," said Graffis. "It's ironic that a health care worker could be a vector of toxins."

The medical center has beefed up it tobacco cessation programs to help employees quit. As for enforcement of the stringent new policy, Graffis noted that smokers are basically "self-incriminating."

"We have no hidden cameras, no Gestapo," he said. "But if they go out and smoke, we'll know."

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