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The harmful agents of third-hand smoke are not yet sufficiently known
39 minutes ago
Have you ever heard of third-hand smoke? The concept is simple and direct: the substances released during the combustion of cigarettes permeate furniture, fabrics or walls.
“And they can stay on these objects and surfaces for days, weeks, months, or even years, and pose health risks,” adds clinical oncologist Marcelo Cruz, from the Sírio-Libanês Hospital in São Paolo.
Although this problem has been described in scientific articles since the 1950s, it is little known in relation to passive smoking, that is to say when an individual who is not a smoker directly instills the smoke evacuated by someone nearby.
A 2009 survey in the United States found that only 43% of smokers believe passive smoking would be harmful to children, while 84% say they are familiar with the dangers of passive smoking.
Experts warn that contact with these chemical compounds can be harmful to health – and some preliminary work with rodents already points to a risk of behavioral disturbances, such as hyperactivity, and even damage to organs such as the lungs and liver.
Understand, below, what we already know about this phenomenon and what we can do to avoid it.
Molecules impregnated
According to the Brazilian Ministry of Health, cigarettes carry more than 4.7 thousand toxic substances. Some of them, like nicotine, naphthalene and formaldehydes, are released during the combustion process and remain in the environment mixed with the smoke.
Gradually, they “stick” to surfaces and objects, especially those covered with fabrics, such as carpets, rugs, towels, curtains and clothing.
Many of these compounds have also been detected as “sticky” to furniture and wall paint.
The first book on the subject was published in 1953 by American doctors. They demonstrated that nicotine condenses (passes from a gaseous state to a liquid state) and, applied to the backs of rats, would cause skin tumours.
In 1991, a survey carried out in Denmark found particles of this same substance (which causes a very strong chemical dependence) in the dust of houses where smokers lived.
In 2008, a group from San Diego State University in the United States evaluated the substances present in the cars of smokers and found that even the dashboard of the vehicle carries the pollutants present in this product, even if the person is not used to smoking while driving.
More recently, in March 2020, a team from Yale University, also in the United States, measured the presence of some of these chemical compounds in a movie theater.
Scientists have found that in films with a more restricted age rating (which indicates the presence of more adults and possibly smokers in this enclosed space), there is a considerable concentration of compounds harmful to health, even though smoking is prohibited in this place.
The authors then concluded that smokers carry these chemicals with them through their skin and clothing, even if they are not smoking at the time. They estimated that the amount of compounds “clinging” to the body of these people is equivalent to the contact of one to ten cigarettes by secondhand smoke.
Finally, Cruz cites a study published in February of this year, in which scientists analyzed the presence of nicotine in the hands of children.
Of 311 volunteers under 12 who had no direct contact with a smoker, 296 (95% of the total) had this substance on the surface of their skin.
In a group of 193 children whose parents were smokers, this rate reached 97.9%.
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Children are more vulnerable to passive smoking
Little known risks
Although experts are concerned about this exposure to so many chemical compounds, there is little research to accurately assess the health effects of third-hand smoke.
After some time, animals exposed to objects contaminated with these chemical compounds exhibited physical and behavioral problems.
The guinea pigs suffered from lung damage and were more prone to suffer from inflammatory diseases such as chronic obstructive pulmonary disease (COPD) and asthma. They also showed changes in the liver that precede conditions such as cirrhosis, cancer and cardiovascular disease.
The scientists also performed behavioral tests and found that rats exposed to third-hand smoke showed signs of hyperactivity more frequently.
Let’s be clear: research of this type is considered preliminary and it is not possible to say with complete certainty that these same problems reproduce in humans. Nevertheless, they serve as a basis for further studies, with human volunteers, to take place in the future.
“Unfortunately, we still have little data on passive smoking and the risk it poses for the development of cancer,” admits Mr. Cruz.
“Despite everything, this problem must be approached with concern, all the more so if we consider children, who are in contact with many contaminated surfaces”, adds the oncologist.
The very size of children facilitates this proximity to carpets and furniture where these cigarette compounds are deposited.
In addition, children are more at risk because they put their hands in their mouths more often and are in the process of forming vital organs and their own immune system.
What should be done ?
Experts point out that the most obvious recommendation to decrease the risk of direct, passive or tertiary smoking is simply not to smoke.
There are treatments that help stop addiction – some of them are even available in the Unified Health System (SUS).
Direct or indirect contact with thousands of substances contributes to the development of more than 15 different types of cancer, not to mention that it is linked to heart attacks, strokes, COPD, tuberculosis, respiratory infections, ulcers stomach and intestine, sexual impotence, infertility and cataracts.
Brazil’s National Cancer Institute estimates that 443 Brazilians die from smoking every day. Each year, 161,000 cigarette-related deaths could be avoided in the country.
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Around 443 Brazilians die from smoking every day.
For those who don’t wish to quit smoking now, the advice is never to smoke indoors or too close to the home, office or public areas.
It seems difficult to remove many of these chemical compounds that “cling” to objects and surfaces. A publication from the Cancer Treatment Centers of America in the United States points out that “normal cleaning methods are not effective against these pollutants.”
“Most of the time, the only option is to change the carpets and paint the walls of the house,” reads the text.
For Cruz, the concept of passive smoking “reinforces the importance of keeping the environment clean and free of cigarettes.”
“As we know, some of these substances can stick around for weeks, months or even years and end up harming the health of people who weren’t even there with the smokers.”
“We are so used to talking about the risks of smoking or passive smoking that we sometimes forget these indirect effects. That is to say, it is not enough to smoke in another room of the house or to open a window to dissipate the smoke”, continues the oncologist.
“You have to think about children and how a habit can harm a whole population that is more vulnerable,” he concludes.