The is inhalation, the mechanism by which both smoking and vaping cannabis work. Beyond that, there are two methods of inhalation: smoking (combustion) and vaping. The difference between the two has everything to do with the temperature at which your cannabis is being consumed. When you light a joint, your cannabis is heated to the point of combustion, and smoke containing THC (as well as carcinogens also commonly found in cigarette smoke) is created via the combustion process. However, when you vape, you’re heating up your cannabis to a much lower temperature (so low that your cannabis isn’t actually burning, hence no combustion) and instead of smoke, you inhale the vapor. Because no combustion is occurring, it is commonly believed that vaping is healthier for you than smoking, although the science to support that claim doesn’t really exist as of yet.
How Combustion Works
Combustion begins at approximately 446 degrees F (230 degrees C) although this temperature varies depending on humidity, potency, composition, and consistency. To reach those high temperatures, most cannabis consumers ignite their flower with fire, usually in a pipe, bong, joint, or blunt. This process creates inhalable smoke containing cannabinoids, some terpenes, charred plant matter, and carcinogenic byproducts unique to the combustion process. It should be noted that while an open flame is probably the most commonly used tool for combustion, it’s not necessary. There are products like the Pulsar APX Smoker that are electronic smoking devices, but not vaporizers. I like Pulsar because they specifically call the APX an electronic combustion pipe, not a vaporizer, specifically because of the temperature at which it heats your cannabis. But you should be wary – there are a lot of brands that don’t market their products as responsibly or accurately as Pulsar. If you are looking to reap the benefits of carcinogen-free vapor and you see a brand that labels themselves as a “combustion vaporizer” just know that this is scientifically impossible and you shouldn’t buy it. It’s not a vape. You should also be careful if you’re in the market for “dry herb vaporizer pens” as a lot of them require you to put your flower directly on the heating coil. There is a significant chance that you’re actually combusting your flower because of this and not vaporizing it. Make sure to read non-sponsored user reviews before making your purchase.
How Vaporization Works
THC converts to vapor at normal atmospheric pressure once temperatures reach somewhere between 250-400 degrees F, notably cooler temperature than the beginning of combustion. Vaporizers optimize cannabinoid content by generating just enough heat to create cannabinoid-rich vapor. Many vaporizers allow consumers to adjust the heat, controlling the cannabinoid and terpene content released into the vapor. Because vaporization methods avoid combustion, the flavor profile and medicinal effects of each inhalation are more complex and potent than what combustion can produce. Additionally, because vaporizers do not burn terpenes, the vapor has a much subtler odor than smoke.
Vaporization Methods: Convection or Conduction
Convection vaporizers, like the Volcano, contain an isolated heating element that does not make direct contact with the cannabis product. Instead, the element heats up the air surrounding the cannabis. A fan or the process of inhalation help to circulate the hot air around the product. Convection vaporizers involve more hardware and are more difficult to maintain. However, they also tend to create an even more flavorful and potent experience than conduction vaporizers.
Conduction involves the transfer of heat directly from one object to another (to remember the difference between convection and conduction, just know that metal conducts heat, and this is the same process that is used to heat up your flower.) Vaporizers that use conduction require the cannabis product to be placed in a chamber that is directly on the heating element. Because of this, it is possible to accidentally combust the cannabis if it is not shuffled around while on the heating element. Because less hardware is necessary for a conduction vape, a lot of mobile vaporizers utilize conduction technology.
Vaporization: The Healthiest Inhalation Method
A 2015 Journal of Respiratory Therapy published a review by Mallory Loflin examining the respiratory risk associated with vaporizing cannabis. After examining the limited research on the topic, Loflin wrote that “preliminary findings do support the idea that vaporization is an improvement over smoking.”
There are two primary reasons supporting Loflin’s conclusion: non-combustion and increased potency.
The primary health benefit associated with vaporization is in its avoidance of combustion. Vaporizers use convection or conduction to heat the cannabis product just enough to turn its cannabinoids and terpenes into vapor without igniting the cannabis. Consequently, the vapor does not contain the carcinogenic byproducts of combustion known as polycyclic aromatic hydrocarbons (PAHs). Additionally, the lower heat associated with vaporizers is less stressful on the consumer’s pulmonary system. Loflin’s review determined that a vaporizer’s mechanisms “adequately reduce risk of pulmonary symptoms” including coughing, wheezing, and tightness in the chest.
The second health benefit to vaporization is in the effect of increased potency. A vaporizer’s low temperature preserves cannabinoids and terpenes that would be destroyed by combustion, leading to an increase in the inhalation of these medicinal compounds. Loflin suggests that the elevated cannabinoid concentration in vapor would reduce the frequency of inhalations. Reducing inhalations is another way to avoid respiratory irritation. It also decreases the likelihood that the consumer will develop an addictive dependence on medicine.
Loflin was clear about the limitations of her research. She noted the lack of long-term, randomized clinical trials on vaporization, stating that “drawing firm conclusions about the impact of the technique is difficult.” In addition to this limitation, there may be one other notable health-related drawback to vaporizing. Ironically, it happens to be one of vaporization’s benefits: increased potency.
A 2018 Jama Open study found that vaporizing cannabis resulted in an elevated concentration of THC in the blood when compared to smoked cannabis, even when the same quantity of cannabis was inhaled. This increase in THC blood concentration was associated with worse cognitive functioning and increased the frequency of adverse responses. This finding also aligns with a 2017 Drug and Alcohol Dependence study, concluding that the benefits of THC are dose-dependent.
Here’s the story the evidence tells: vaporization does not cause the same respiratory irritations as smoking, and that is its primary health advantage over combustion. But healthier—even healthiest—does not mean risk-free. As Dr. EB Russo explains in a 2016 Frontiers in Pharmacology review, current evidence on the safety of vaporization is so underwhelming, it “would have little sway among regulators in most nations.”
Combustion: The Most Popular Inhalation Method… For Now
Loflin’s review noted that cannabis smokers experienced the symptoms of bronchitis as a result of combustion. A Respiratory Care review by Dr. Mary Martinasek published a year later confirmed Loflin’s findings, indicating that the inhalation of marijuana smoke is associated with wheezing, shortness of breath, altered pulmonary function tests, cough, and phlegm production.
Martinasek’s review also noted that smoked cannabis was associated with bronchodilation, the body’s way of increasing airflow to the lungs. Several compounds in cannabis have been identified as bronchodilators, including the terpene pinene and cannabinoid THC. Additionally, a 2012 Jama Network study examining the long-term (20-year) impact of smoking cannabis on pulmonary function concluded that “occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function.” These combined findings suggest that it is the uniquely deleterious effects of frequently inhaling the smoke that leads to respiratory depression in cannabis smokers.
Despite the possible adverse respiratory effects of smoking, cannabis combustion via bowl, bong, joint, and the like remains the most popular method of inhalation. Inhalation is one of the quickest means of delivering cannabinoids, which makes it ideal for consumers seeking quick relief or recreation. It is also easier to titrate dosing by controlling the frequency and style of inhalation.
While vaporizing is rapidly gaining popularity, smoking cannabis has been around hundreds of years longer than the low-heat alternative. It can also be one of the most low-tech inhalation options. Vaporizer technology can get complicated and expensive. If you want to smoke, all you need is a bowl (or an apple) and a flame. Given its rapid effect, convenience, and historical entrenchment in cannabis culture, combustion remains the simplest and most recognizable form of consuming. Regardless of its placement in the health spectrum, smoking pot is likely here to stay.