How Bad is Cannabis Secondhand Smoke?

You may be old enough to remember the earliest tobacco commercials and print advertisements. Smoking tobacco has been a thing in America since the 1700s, but when tobacco became commercialized, it was cool, fun, and perhaps even a benefit to your mental health.

Everyone thought it was safe until it wasn’t. The first alarm bell sounded when the U.S. Surgeon General, Luther L. Terry, M.D., released a public health advisory on January 11, 1964. The Surgeon General’s Advisory Committee on Smoking and Health learned that smoking was 1) A cause of lung cancer and laryngeal cancer in men, 2) A probable cause of lung cancer in women, and 3) The most important cause of chronic bronchitis.

It would take another thirty years before the death toll of cancer would force the facts about tobacco smoke exposure and health risks. Unlike tobacco, there are very few studies about secondhand cannabis smoke exposure today, but many potential health risks are understood.

Whether you consume smokable cannabis at home or live with someone who does, there are some important things to know about secondhand cannabis smoke that can help you protect your health.

The World Record Holder for Smokable Cannabis Consumption

We couldn’t talk about cannabis smoke without sharing something interesting about a man named Irvin Rosenfeld. If ever there was an expert about smokable cannabis, it may be Irvin and perhaps anyone who has spent a lot of time around him.

Irvin Rosenfeld is the world record holder for smoking the most cannabis, and he lives in Fort Lauderdale, Florida. What is most fascinating is that he has been doing it with permission from the federal government since the early 1980s.

In 1982, Rosenfeld was enrolled in the “Experimental New Drug Research Program,” one of the new federal and commercial drug testing programs. From the perspective of cannabis legal reform, Congress has taken a very long period to think about the legalization of medical and adult-use cannabis.

Irvin Rosenfeld received free pre-rolls every day from the government for thirty years. The stockbroker from Fort Lauderdale visits a pharmacy to pick up 300 pre-rolls every month as part of the continuing program. Rosenfeld uses medical cannabis for a painful, incurable condition called multiple congenital cartilaginous exocytosis.

As the longest-surviving member of the Federal Medical Cannabis patients in the study, Irvin Rosenfeld has been a powerful cannabis patient advocate, and he is the founder of “The Silver Tour,” a charitable organization that educates seniors about the benefits of medical cannabis.

In 2014, Irvin Rosenfeld was inducted into the Guinness World Records Book for consuming over 115,000 joints. That earned Rosenfeld “the most marijuana consumed” in all of recorded human history.

Is Cannabis Smoke Less Harmful Than Tobacco Smoke?

Thanks to education about the health risks of tobacco smoke, most people know that it has harmful effects not only for the individual smoking tobacco but also for anyone else near them who may be breathing in secondhand tobacco smoke.

There is a prevailing myth that cannabis smoke exposure is safe when compared to tobacco smoke. However, while there are far fewer chemicals inhaled when smoking marijuana, there are still carcinogens and other chemicals that can cause respiratory damage.

Tobacco Smoke Vs. Cannabis Smoke

A study by the University of California San Francisco and the University of Alabama at Birmingham reviewed health data from 5,000 American adults spanning over twenty years. It was the first major study in the world that evaluated the long-term cardiovascular and respiratory effects of tobacco use and smoked cannabis.

The study reported that:

• The more tobacco you use, the greater the loss of air flow rate and lung volume. The heavier you smoke cigarettes or other tobacco products, the more substantial the respiratory damage occurs.
• The airflow rate improved rather than decreased with increased exposure to marijuana smoke (to a degree).

That sounds like pretty good news for people who prefer to smoke cannabis. But, back in 2012, researchers estimated that tobacco smokers may consume 10-20 cigarettes per day, whereas people who used cannabis typically only smoked 2-3 times per month. Post-legalization, that estimate is no longer accurate, with some reports that number is closer to 2-3 per week.

Cannabis smoke can be less harmful than tobacco smoke, but only if smoked in smaller quantities and frequencies. Many physicians support using other intake methods that may be less harmful to the respiratory tract, including tinctures, capsules, and edibles.

Health Risks Associated With Secondhand Cannabis Smoke

Hands up if you thought that cannabis smoke was less harmful than tobacco or cigarette smoking. If you look up the list of carcinogenic and health-harming chemicals in cigarette smoke, there are more than 5,000. The unofficial number of chemicals in cannabis smoke is 100.

When you compare the two, it is easy to see why people accept cannabis as less harmful than tobacco smoke. Less chemicals, however, does not mean harmless to human health. If you are deciding what intake method to try, there are some important things to understand about smoked cannabis.

Inhalation of Cannabis Particulates

When cannabis flower is combusted, the smoke contains very fine particulate matter. So fine, in fact, that it is not visible in the vapor. Because the particulates are so small, they are easily inhaled deep into the lungs and can cause serious lung irritation and health risks for individuals with conditions like asthma, emphysema, or COPD.

Heavy Metal and Chemical Carcinogen Exposure

All medical cannabis cultivated by licensed dispensaries has quality assurance and product safety practices in place. It is required by state law, and cannabis growers, processors, and manufacturers are legally liable if they fail to provide safe products.

Cannabis that is purchased from an illicit drug provider is not safe. There are no batch inspections for street cannabis, and you never really know what you are getting. Several studies over decades have found heavy metals such as nickel, lead, chromium, mercury, and cadmium in cannabis flower.

Cannabis smoke can also create three times the amount of ammonia and a higher quantity of hydrogen cyanide compared to tobacco smoke. These chemicals are rapidly absorbed when cannabis is inhaled through direct use or secondhand cannabis smoke.

Cardiovascular Risks Are Equal

Both secondhand tobacco smoke and cannabis have an equal risk of causing cardiovascular damage not just to the smoker but to anyone in the area who is breathing in the vapors. Secondhand smoke from both substances can increase the risk of atherosclerosis (blocked arteries), heart attack, and stroke.

Secondhand Marijuana Smoke Impairs Blood Vessel Function

In clinical studies, both tobacco smoke and cannabis smoke exposure impacted normal blood vessel function. However, after 30 minutes of exposure to secondhand cannabis smoke, the cannabis had a larger negative impact on blood vessel function, and the effects lasted longer when compared to tobacco smoke.

Smoking (any substance) is a top risk factor in the development of vascular disease. When vessels constrict, or there is impairment in the blood flow of arteries and veins, it can cause adverse effects, such as heart attack, stroke, and blood clots.

Emissions from Cannabis Smoke Higher Than a Malboro

Researchers in one study found that the volume of particulates in secondhand marijuana smoke from a pre-roll was 3.5X higher than Marlboro tobacco cigarettes. When you think about the volume of smoke alone (cannabis exhale versus tobacco smoke), it makes sense; visually, you can see that cannabis clouds are thicker and dense.

There may be fewer carcinogenic chemicals in cannabis smoke compared to tobacco smoke, but when you are consuming it (or in the same room), marijuana smoke is over three times greater in volume. That means more potential respiratory risks from cannabis secondhand smoke.

Reducing Marijuana Secondhand Smoke Exposure

If you live with family members or friends who do not use cannabis, the most effective way to reduce marijuana secondhand smoke exposure is to smoke exclusively outside. The open-air ventilation system in your own backyard or balcony is by far the most efficient way to disperse vapors. Make sure windows and doors are also closed.

People who do not have easy outdoor access can use the open-window method. If cannabis has to be consumed indoors, ensure it is in a very well-ventilated location, away from children, pets, and non-smokers. Be aware of non-smoking regulations in your rental home or apartment.

One of the reasons why edibles are so popular is because they are convenient to use and an effective way to consume medical cannabis. No pipe or pre-roll, no incineration, and no need to inhale cannabis. There is also no cannabis secondhand smoke to worry about when you use inhalers, tinctures, or capsules.

Cannabis smoking is a preference for many patients. However, if you are experiencing problems with chronic bronchitis, asthma, persistent cough, or changes in regular breathing, talk to your physician about your symptoms. Then, speak to a Massachusetts medical card healthcare provider about non-smokable medical cannabis options.