Secondhand Marijuana Smoke a Danger to Kids

Health Professional, Medical Reviewer

Marijuana has become socially acceptable and more prevalent due to medicinal use. It’s now available in many medicinal markets nationwide, and its recreational use is approved in many states. Although there are regulations regarding use in public places, there is no current viable control for the use of marijuana in the privacy of one’s home. Smoking marijuana poses secondhand smoke dangers similar to tobacco smoke.

What are the real effects of that secondhand smoke exposure on non-smokers living in close proximity where marijuana is smoked? This is a legitimate question, especially for children living in close quarters of apartment buildings and urban areas.

How second hand smoke affects children

One study presented at the Pediatric Academic Societies May 2018 meeting looked at the effect of the secondhand marijuana and tobacco smoke exposure on children. This study involved data from a survey done at an academic center in a children’s hospital in Colorado. The researchers noted that there was an increase in emergency room visits for asthma, ear infections, and other respiratory infections in those children whose caregivers were regular smokers, compared with children whose caregivers were not smokers.

The effects of most environmental substances like smoke on children is more dramatic since they have much smaller bodies with smaller surface areas, allowing for concentrated exposure and distribution. Their airways are also smaller in diameter. When they inhale secondhand smoke, it can linger for longer periods of time. They are therefore, more prone to airway inflammation and obstruction and risk of asthma.

This is not the first time that marijuana smoke has been shown to have a secondary effect on individuals who are non-smokers but who live in close proximity to the smoke exposure.

Non-smokers can still test positive

A separate study measured the amount of tetrahydrocannabinol (THC), the psychoactive component of marijuana, in the blood of non-smokers, who had spent three hours in a space with marijuana smokers. This study showed that there was THC present in the blood of those nonsmokers.

In this second case, some of the subjects who were exposed to high THC concentrations of marijuana smoke also had sufficient absorption of THC, to fail a urine drug test specific to marijuana use.

Second and thirdhand impacts

Other studies also demonstrate an association of secondhand marijuana smoke exposure with the sensation of (self-reported) psychoactive effects and respiratory irritation. It’s important to note that the relationship between exposure and impact of secondhand smoke is affected by many factors including:

  • The THC content and potency of the marijuana involved
  • Amount of smoke
  • Ventilation variables including amount of fresh air present
  • Space size
  • Number of cigarettes lit
  • Number of smokers in the space

These variables are not only pertinent to second hand smoke exposure, but also figure in thirdhand smoke exposure. Second hand smoke exposure occurs when smoke exhaled by a smoker or emitted from the burning substance is inhaled by an individual in close proximity. Third hand smoke exposure results from the residual tobacco and marijuana smoke pollution in the environment after the smoking has stopped.

Residual contaminants from cigarette and marijuana smoke left on clothing, furniture, walls, carpet, floors, and other surfaces can become airborne by any factors that disturb the environment and then spread the contaminants through a building ventilation system.

How smoke interacts with the environment

The mechanism by which smoke persists is related to its various stages. Once smoked, THC is initially released in the vapors and then, in the presence of nitrogen found in the room air, it converts into an aerosol which persists for a while. This aerosolized stage is accompanied by the risk of contamination with other indoor molds that may be present, bringing a new element of risk that is not present for the original smoker. It’s a risk for the bystander.

What is more disturbing is that individuals are at risk for exposure even when they are not in the same room with the smokers, but just in close proximity.  This raises a level of alarm with regards to children who live in a household of non-smokers but have a neighbor who is a regular smoker.

Separate research was done to evaluate the environmental contaminants in a classroom empty for 30 days, that was 20 meters away from where people actively smoked and also near another office of smokers with a shared HVAC system. The researchers found the same type of residual contaminant (aerosolized smoke vapors mixed with molds) that lingered for the entire 30 days. This suggests that there is a unique particle contaminant that remains indoors and is linked to third hand smoke.

Although this particular study only evaluated a 30-day period, it’s postulated that these particles can remain for years. Of serious concern is that when third hand smoke is present, there is a constant source of exposure day after day.

I’ve previously discussed the effects of third hand smoke particles on pets since they have persistent close contact with furniture. The findings from the May 2018 study suggests that beyond secondhand exposure, this thirdhand phenomenon may also affect children.

Safety must be reevaluated

The complexities of marijuana smoking are the result of the thousands of products of combustion that are unpredictable. Some of them can be dangerous, particularly nitrosamines, which are known carcinogens. This carcinogen is something that all substances that are smoked share in common.

Individuals who believe that marijuana is not as dangerous to one’s health compared to cigarettes, because of the perceived beneficial medicinal effects, need to consider the compelling argument of the dangers of primary, secondary, and thirdhand smoke exposures.

Currently the only policies in place to protect non-smokers from the effects of smokers are restricted to smoking prohibitions in some public places. As we enter an era of overcrowding in inner cities with large apartment dwellings and more acceptable use of marijuana smoking, these studies raise serious concerns and highlight the need to reevaluate the safety issues and public health mandates surrounding any type of smoking.

See more helpful articles:

Studies: Marijuana Benefits Overstated, Lung Damage is Real

The Dangers of Thirdhand Smoke

13 Sizzling Questions about Marijuana and Chronic Pain