Passive smoking: why is it so dangerous? How can it be prevented?

By expelling smoke from his or her cigarette, a smoker intoxicates those around him or her, starting with children. This passive smoking has a significant impact on health.
Passive smoking: why is it so dangerous? How can it be prevented?
In general, smokers are aware of the risks to their own health: lung cancer, cardiovascular disease... But they are not always aware of the dangers to which they expose those around them. Passive smoking affects children, spouses, co-workers, friends, and anyone who unknowingly inhales toxic tobacco smoke.

Passive smoking: maximum risk at home or in the car

The risk peaks in enclosed and poorly ventilated areas, such as a home or car, and increases with the duration of exposure. When the smoker exhales the smoke from his or her cigarette, the products of combustion, whether gases or particles are dispersed into the air. They will then settle on furniture and settle on the fabric of armchairs, curtains, or clothing. "Our studies have shown that these particles can persist for several days," says Professor Isabella Annesi-Maesano, Director of Research at Inserm, a specialist in the epidemiology of allergic and respiratory diseases. 

These chemical compounds can also interact with other indoor air pollutants (formaldehyde, ozone...) and, through a chemical reaction, form secondary pollutants just as dangerous as those from tobacco. Some are carcinogenic.

If they are evident in closed rooms, it should be noted that the risks of passive smoking persist outside, for example on a terrace or a beach. "These risks have been demonstrated within a few meters of a smoker by measuring nicotine, a marker of exposure to passive smoking, under stable conditions such as the absence of wind," explains Prof. Annesi-Maesano. This is, moreover, the reason why many beaches are closed to smokers.


Who are the so-called passive smokers?

Children are the first victims

Those most vulnerable to second-hand smoke are children, pregnant women and people weakened by the disease. During pregnancy, harmful substances pass from the mother-to-be's blood to the fetus. A recent study by Inserm, CNRS, and the University of Grenoble shows that the placenta retains a trace of this intoxication, in the form of DNA alterations, even in women who stopped smoking three months before becoming pregnant.


Pets also suffer from second-hand smoke.

Pets are not immune to passive smoking. Studies have shown that exposure to tobacco smoke can cause respiratory problems, weight gain, and cancer in dogs, cats, and even goldfish that are highly sensitive to nicotine and ammonia from tobacco. Cats that frequently lick their fur appear to be particularly at risk. 


Passive Smoking: Same Health Effects as Tobacco

The fine particles and volatile organic compounds derived from tobacco penetrate very deeply into the body and will particularly affect the heart and lungs. Consequences: the risk of developing lung cancer or cardiovascular disease is increased by 25% in a person exposed to passive smoking. Some studies also establish a link with other types of cancers (larynx, pancreas...). 

Smoking during pregnancy affects the growth of the fetus and greatly increases the risk of giving birth to a baby weighing less than 2.5 kg.

In newborns, the risk of sudden infant death syndrome (SIDS) is doubled if one of the parents is a smoker. The proportion is even higher if both parents smoke.

Later in childhood, the entire ENT sphere is impacted by passive smoking. For example, the risk of bronchitis increases by 72% and 48% for ear infections. 

Also, many studies have shown that a child whose mother smoked has an increased risk of becoming asthmatic. "In the United Kingdom, a study has even shown that this risk exists if the grandmother was a smoker, while the mother was not," says the researcher. 

Finally, a study presented in 2015 by Professor Annesi-Maesano and her team showed that school-age children, exposed to passive smoking before and after birth, have more behavioral problems (withdrawal, agitation, etc.) than their peers. "We hypothesize that nicotine attacks developing neuronal cells," she says.


The best solution is to make it big, the best solution

To protect yourself from passive smoking, ventilation is the best solution. Windows should be opened wide, very regularly, to dilute the harmful substances in the ambient air; and don't forget to clean all surfaces on which tobacco smoke is deposited.

Air purifiers, devices that are supposed to filter pollutants, are not enough to clean the atmosphere. "It's far from being effective. They don't catch the ultrafine particles that are the most dangerous," says Professor Annesi-Maesano.


Protective laws for non-smokers

Since the Evin law of 1991, a succession of legislative measures has made it possible to better protect the population against the dangers of passive smoking.

  • Since 2007, smoking has been banned in all public places, cafés, restaurants, hotels, public transportation, and workplaces.
  • Since 2015, it is also forbidden to smoke in a vehicle in the presence of a minor child under 18 years of age. 

These measures have had an impact, but it still seems insufficient. According to data published by Public Health France in February 2020, 15.7% of adults reported in 2017 having been exposed to tobacco smoke in their workplace. Workers are more affected by passive smoking (27.4%) than managers and senior professionals (6.4%).

Efforts are greater in the private sphere. While 52% of daily smokers smoked at home in 2014, by 2018 only 37.9% were smoking at home. It seems that these smokers have become aware of the dangers of second-hand smoke for children since the frequency of smoking at home in households with a child under 4 years of age has increased from 31.6% in 2014 to 14.4% in 2018. 


A number of victims poorly evaluated

The number of deaths attributable to secondhand smoke remains poorly estimated. In 2002, one study gave a range of 1,000 people (taking only non-smokers affected by passive smoking) to 6,000 deaths per year (including smokers themselves affected by passive smoking) in France. 

Beyond these very imprecise figures, Prof. Annesi-Maesano points out that currently, more than 30% of French people smoke, which leads him to this conclusion: "The risk of contact with tobacco smoke remains high. »