Vaporisers

A vaporiser is a device used to produce a vapour from heated cannabis which users then inhale. Unlike a joint or bong, vaporisers heat cannabis below combustion temperature, which means that smoke is not produced.

The first vaporiser to be mentioned in the literature was the Tilt, commercially marketed in the United States in the early 1980s before anti-paraphernalia laws were passed.1However, according to a number of websites, the first electric vaporiser prototype, the BC Vaporiser, was not produced until 1994 in Canada.2,3 It was this vaporiser that was used by the California NORML (National Organization for the Reform of Marijuana Laws) and Multidisciplinary Association for Psychedelic Studies (MAPS) in a study of seven different smoking devices in 1996.4

Since that time there have been a variety of changes made to the vaporiser with patents being filed for additions such as a removable valve balloon for the Volcano inhaler in 1998, and a heating block as a heat exchanger for hot air extraction inhalers in 2000.3

Currently, there are a number of vaporiser designs on the market, many of which are sold online. Many vaporisers use a hotplate to heat the cannabis while other varieties may use a hot air gun and may also filter the vapour through water before releasing it to be inhaled.4 Some vaporisers blow hot air through a disk containing cannabis5 while other home-made varieties are even fashioned from light bulbs.6 One of the high end varieties of vaporisers available is the Volcano Vaporiser. This device contains a heater or hotplate, a ventilator, a filling chamber, a valve, a balloon and a mouth piece.7 Once the cannabis is heated, the vapour is funnelled through a valve by an air pump and fed into an inflatable, plastic, balloon-type bag. When the balloon is filled, it can be removed from the device and the vapour inhaled.5

Many cannabis users who prefer to use vaporisers believe that they are safer than waterpipes ( bongs ) or joints. There is the belief that because the cannabis is not combusted, they are protecting themselves from the harmful and carcinogenic chemicals produced by smoke. In the words of one cannabis user, What's good about a vaporizer is that you don't inhale smoke you inhale vapor making it much healthier. Another good thing is that you only need a small amount of herb [cannabis]. The only downside I see is that it's kinda pricey .6

One company selling vaporisers online claims that using the device reduces the development of harmful substances and odours to a minimum and that non-smokers in the room will not be adversely affected due to the absence of smoke and odour.5 These claims are primarily marketing tools and may not be indicative of the actual effect on the user or others.

Cannabis smoke is the result of heating cannabis until it burns, at its combustion temperature of approximately 230 C. Vapour, however, is produced by heating, but not burning the drug. This is usually achieved at temperatures between 170 C and 200 C, although higher temperatures are possible.9,10 Cannabis smoke contains gaseous and particulate matter including noxious tars, carbon monoxide, toluene, naphthalene, acetaldehyde, phenol and hydrogen cyanide, many of which are at similar levels to those that have been identified in tobacco smoke, all of which are capable of causing significant respiratory symptoms.1,12 Studies examining particular types of vaporisers, however, have indicated that some may produce a vapour that does not contain cancer-causing polycyclic aromatic hydrocarbons (PAHs)9,11 that are found in cannabis smoke.

It has also been claimed that using a vaporiser produces less toxic by-products and extracts THC more efficiently than smoking the drug in a bong or joint.10 Other studies have found that compared to bongs and joints, using vaporisers led to fewer respiratory symptoms12,13 and were capable of achieving reductions in tar relative to THC .7 Cannabis vapour has also been found not to contain a measurable amount of harmful chemicals found in smoke such as benzene, toluene and naphthalene. Lower levels of tar and carbon monoxide were also found in cannabis vapour compared to cannabis smoke. There have also been suggestions that vaporisers allow THC to be absorbed more quickly into the body than joints or bongs.5,9

A limitation of these studies is that many have not tested for the presence of tar or toxic gases with a low molecular weight, such as ammonia or hydrogen cyanide.11 One study that did test both cannabis smoke and vapour for the presence of ammonia, found toxic levels of ammonia in vapour but far lower levels in smoke.14Another potential risk when using vaporisers is that toxic chemicals that would otherwise be lost in the sidestream smoke of a joint (and thus not inhaled by the user) are not able to escape in a vaporiser. This means the user has more chance of being exposed to toxic chemicals by using the drug in this way.14 Studies on the effect of inhaling ammonia have found that it can cause irritation and central nervous system effects with no evidence of adaptation over the exposure period... [and] neurobehavioural impairment . Exposure to ammonia has also been linked to asthma and bronchial spasms.14

There are also many variables that could affect the testing of vapour, such as the type of vaporiser used, temperature variations, cannabis potency, density of the plant matter used, how long the vapour is stored in the balloon and the parts of the cannabis plant used.8,11 In fact, even a company selling vaporisers online warns that not all studies on cannabis vapour have been conducted with the required scientific rigor and that the results from such tests vary significantly.8 One study which sampled over 6000 people in an online survey found that those who used vaporisers reported fewer respiratory symptoms than those who used bongs or joints. The study authors, however, emphasised that there were limitations to this study including that it was conducted over the internet, that in order to find regular cannabis users they targeted people with a potential interest in changing cannabis policy , thus injecting bias into the results, and that those who use vaporisers often spend a lot of money in an effort to minimise respiratory harms from their cannabis use and are therefore more likely to minimize reports of their respiratory symptoms, consciously or inadvertently, in an effort to justify their actions .12

Despite the fact that results from some studies that have analysed and compared cannabis vapour and smoke appear to show lower levels of by-products, carcinogenic chemicals and noxious waste by-products such as PAHs in vapour,4,7,10,11 there is no safe way of inhaling cannabis and any inhalation of cannabis vapour will cause some level of bronchial irritation. As stated earlier, toxic levels of ammonia were found in cannabis vapour, at far higher concentrations than in cannabis smoke produced from joints.14 Eating cannabis in food or capsules1,12 or drinking it as tea or in tinctures are the only methods that completely remove the respiratory harms associated with inhaling cannabis smoke or vapour.1 These methods, however, have their own risks, as ingested cannabis can take over an hour to be absorbed and overdose and panic reactions may occur.1

No matter what method someone uses to use cannabis, they are still subject to risks associated with cannabis use such as mental health problems, dependence, legal issues and diminished driving skills.12 Further research needs to be conducted in order to gain a clearer picture of the benefits and harms associated with vaporisers in comparison to other methods of administration.

References

    1. Gieringer, D.H. (2001). Cannabis vaporization : A promising strategy for smoke harm reduction. The Haworth Press. Accessed from http://www.cannabis-med.org/data/pdf/2001-03-04-9.pdf on 27 February 2012.
    2. BC Vaporizer.com (2012). History of the BC Vaporizer. Accessed fromhttp://bcvaporizer.com/history_of%20_he_bc_ vaporizer/history%20of%20BC%20Vaporizer.html on 9 March, 2012.
    3. Vaporizer Info (2012). What is a vaporizer? Accessed from http://vaporizer-info.com/en/what-vaporizeron 9 March, 2012.
    4. Gieringer, D. (2000). Marijuana water pipe and vaporizer study. Newsletter of the Multidisciplinary Association for Psychedelic Studies MAPS 6(3). Accessed from http://www.maps.org/news-letters/v06n3/06359mj1.html on 23 February 2012.
    5. Vaporizergiant.com (2008). Vaporizergiant.com, Why vaporize? Accessed fromhttp://www.vaporizergiant.com/ why_vaporize.html on 23 February 2012.
    6. Weedmaps Media Inc. (2012). Marijuana.com, What is a vaporizer? Accessed fromhttp://www.marijuana.com/ threads/what-is-a-vaporizer.177157/ on 23 February 2012.
    7. Hazekamp, A., Ruhaak, R., Zuurman, L., Van Gerven, J., & Verpoorte, R. (2006). Evaluation of a vaporizing device (Volcano) for the pulmonary administration of Tetrahydrocannabinol. Journal of Pharmaceutical Sciences 95, 1308-1317.
    8. Vaporizergiant.com (2008). Vaporizergiant.com, Smoke vs. vapour. Accessed fromhttp://www.vaporizergiant. com/smoke_vs_vapor.html on 23 February 2012.
    9. Abrams, D., Vizoso, H.P., Shade, S.B., Jay, C., Kelly, M.E., & Benowitz, N.L. (2007). Vaporization as a smokeless cannabis delivery system: A pilot study. Clinical Pharmacology & Therapeutics 82, 572-578.
    10. Pomahacova, B., Van der Kooy, F. & Verpoorte, R. (2009). Cannabis smoke condensate III: The cannabinoid content of vaporised Cannabis sativa. Inhalation Toxicology 21, 1108-1112.
    11. Gieringer, D., St. Laurent, J. & Goodrich, S. (2004). Cannabis vaporizer combines efficient delivery of THC with effective suppression of pyrolytic compounds. Journal of Cannabis Therapeutics 4, 7-27.
    12. Earleywine, M. & Barnwell, S.S. (2007). Decreased respiratory symptoms in cannabis users who vaporize. Harm Reduction Journal 4.
    13. Van Dam, N.T. & Earleywine, M. (2010). Pulmonary function in cannabis users: Support for a clinical trial of the vaporiser. International Journal of Drug Policy 21, 511-513.
    14. Bloor, R.N., Wang, T.S., Spanel, P., & Smith, D. (2008). Ammonia release from heated street cannabis leaf and its potential toxic effects on cannabis users. Addiction 103, 1671-1677.

Research Brief published November 15, 2012.