Research has shown that potentially dangerous residues can be absorbed through the skin, taken up and inhaled, months or even years after the smoke has decomposed
WASHINGTON: First came warnings from doctors about cigarettes. Then came discoveries about the danger of passive smoking. Now more and more scientists are raising alarms about third-party smoke – residual chemicals left behind by tobacco smoke on the inside surfaces.
Research has shown that such potentially dangerous residues can be absorbed through the skin, absorbed and inhaled even years after the disappearance of the smoke.
A study this year showed that the risk of lung cancer in mice was increased by third-party smoking. Another study last year showed liver damage and diabetes in mice. A third study focused on casinos this year, showing that six months after the ban on smoking, heavy smoke remained on the walls and carpets.
The latest study, published in the journal Science Advances shows how outdoor tobacco smoke can penetrate into a non-smoking classroom and coat its surfaces, and how these dangerous chemicals often escape into the air and to circulate through central air conditioners in buildings.
"It shows that just because you're there A smoke-free environment does not mean you're not exposed to tobacco," said Peter DeCarlo, a chemist at Drexel University in Philadelphia who was the lead author of the study. "The car you leap into, the hotel room you stay in, even a classroom that has not been smoked for decades: these are places you are often exposed to much more than you expect."
The latest findings were in some ways an accident.
DeCarlo, who studies outside air, had teamed up with an interior air expert at Drexel, Michael Waring, to investigate how the two interacted. A graduate student working with them examined chemicals in a classroom about 20 yards from DeCarlo's office and came across a mysterious chemical signature they could not explain.
First, they suspected residues of coffee, which is ubiquitous in universities. But after a series of tests, they were surprised to find signs of nicotine and tobacco smoke. To replicate the chemical signature, they performed a series of experiments, blowing cigarette smoke into a Pyrex glass jar, extinguishing the smoke, and leaving the glass to rest for a week. The residues were exactly the same, they found.
So they turned their investigative efforts toward the classroom and ran a series of tests pumping outside air into and out of the room.
They found that tobacco smoke can enter interior spaces and adhere to surfaces. Then, especially in the summer, when rooms are blasted by air conditioning, the chemicals are not only released back into the air, but can also easily spread through the ventilation system of buildings.
"This brings a turn to what we are just beginning to discover ̵
Public health experts have collected mountains of data on how lethal smoking is. And they have huge data on the dangers of secondhand smoke. But the idea of third-hand smoking only began to emerge in the last decade.
Research into their health implications suggests that it could be harmful, but data remain scarce and are mostly limited to studies with mice. However, researchers are confident that tobacco smoke chemicals often dwell on clothing, surfaces and even skin.
Public health advocates worry that those who are particularly vulnerable to the harmful effects of third-party smoke, even those who are likely to come in contact with it. For example, a baby crawling on the floor has much more contact with carpets that often contain cigarette fragments. And due to increasing socio-economic disparities in smoking, low-income families tend to live in homes and neighborhoods where decades of smoking have led to third party smokescence.
"I do not think we have any idea how big the problem is," said Matthew L. Myers, president of the campaign for tobacco-free children. "So far it has not been possible for scientists to say how widespread and serious the risk is, but what we have already seen contributes only to the reasons that should be banned in public places."
Growing research on such residues has led lawmakers to consider legislation prohibiting smoking in rooms such as childcare facilities, even outside the hours when there are no children present.
The American Academy of Pediatricians has issued recommendations to limit the exposure of children to third-party smoke. And in recent years, California has established a new consortium of scientists funded by state cigarette taxes to research the mechanics and potential hazards of third-party smoke.