Vaporizer
Encyclopedia
A vaporizer or vapouriser is a device used to extract for inhalation
the active ingredients of plant material, commonly cannabis
, tobacco
, or other herbs or blends.
Vaporization
is an alternative to burning
(smoking
) that avoids the production of irritating toxic
and carcinogen
ic by-products by heating the material so its active compounds boil off into a vapor
. No combustion occurs, so no smoke or taste of smoke is present. Vapor ideally contains virtually zero particulate matter or tar
, and significantly lower concentrations of noxious gases such as carbon monoxide
. Vaporizers contain various forms of extraction chambers including straight bore, venturi
, or sequential venturi, and are made of materials such as metal or glass. The extracted vapor may be collected in a jar or inflatable bag, or inhaled directly through a hose or pipe. With little to no smoke produced and cooler temperatures, less material is required to achieve a given level of effect. Hence, the irritating and harmful effects of smoking are reduced, as is secondhand smoke
.
Precise vaporizers use an electric heating element, often featuring thermostat
ic temperature control. High-end models may cost several hundred US dollars.
Broadly, vaporizers may be classified by how they heat the substance:
In conduction heating, the substance is placed on a metal plate that is then heated to release the active constituents. Conduction vaporizers were the first type to appear on the market, and are still in production.
In convection heating, the substance never touches a heating element. Instead, hot air passes through it, heating it rapidly, and allowing the release of the active constituents. This method of heating releases more active constituents than conduction heating. Some convection vaporizers or vaporization systems use a hand-held heating wand with a glass-encapsulated element and vortex flow form inducing intakes, which when mated to a bowl on many common pipes or water pipes or when mated to a specialized vaporization chamber bowl, enable the user's draw to pull ambient air past a glass heating surface heating the air prior to its passage through the substrate in the bowl. The vapor is extracted and then passes through the pipe, often with water and/or ice for cooling and conditioning, and thence to the user.
Many convection vaporizers use a long flexible drawtube ("whip") through which the user inhales the vapors, reducing their temperature on arrival. Some vaporizers have a bag or balloon attachment; vapor is blown into the bag, and the user detaches the bag and inhales the contents. Attachments can be placed between the vaporizer or bag and the user's mouth to cool the vapor with water or ice.
Convection vaporizers are either forced-air types which actively blow air through the heating element and herbs, or passive types, where the user inhales the air without the help of a fan or pump. Most vaporizers today use the convection principle, including heat guns, "wood box" types, and nearly every higher-end vaporizer available.
In radiation heating, the substance absorbs radiant energy and its temperature rises. The energy can be provided by a superheated thermal mass placed around it, or from a visible bright light source like the sun. Thermal mass radiation vaporizers permit uniform heating of substate without diluting vapours, supplying high quality medicine. A pipe and a magnifying glass on a bright, sunny day can, with care and practice, act as an adequate radiation vaporizer.
, Cannabinol (CBN)
, and delta-9-tetrahydrocannabinol (THC)
do not vaporize until near their respective flash point
s: CBD 206.3°C, CBN 212.7°C,and THC 149.3°C. Because most commercial vaporizers are slow in extraction and delivery, the vapor inhaled is first aromatic, but only minimally active; as the plant material temperature rises, the vapor becomes increasingly bio-active, but minimally aromatic, because most of the aromatics have already been released. This problem is addressed in the modular vaporization tool-based systems by use of a sequential venturi effect for more rapid extractions via a vaporization chamber bowl and vaporization heat wand or heat gun and is addressed in some box vaporizers by way of a venturi-inducing extraction intake prior to the hose. With the vaporization chamber bowl approach, many common pipes can be modified, enabling the delivery of broader-spectrum vapor preferred by many users and higher in concentration, consistency, and aromatic density due to the increased rate of extraction and smaller sample size. Bag capture vaporizers tend to be slower in extraction rate, which prevents the attainment of fuller spectrum vapor, but are more convenient to use.
A study published in the Journal of Psychopharmacology in May 2008 investigated the acceptability and usefulness of intrapulmonary THC administration using a vaporizer and pure THC instead of cannabis. Rising doses of THC (2, 4, 6 and 8 mg) were administered with 90 minutes intervals to twelve healthy males. Very low between-subject variability was observed in THC plasma concentrations, characterizing the vaporizer as a suitable method for the administration of THC.
In 2007 a study by University of California, San Francisco
published in the Journal of the American Academy of Neurology examined the efficacy of a vaporizer that heats cannabis to a temperature between 180 °C (356 °F) and 200 °C (392 °F) degrees and found:
In 2006 a study performed by researchers at Leiden University
tested a vaporizer with preparations of pure THC and found that:
When using plant material (crude flower tops), besides THC, several other cannabinoids and a range of other plant components including terpenoids
were detected in the plant material. However, using pure THC in the vaporizer, no degradation products (D8-THC
, CBN
, or unknown compounds) were detected by HPLC
analysis. Also, a substantially larger fraction of the THC was delivered to the vapor by using pure THC.
Analysis of the vapor from the vaporizer found that using multiple passes it delivered 36%–61% of the THC in the sample. A study using pure cannabinoid preparations achieved a maximum of 54%. Studies of cannabis cigarettes smoked via a smoking machine under varying conditions of puff duration and air speed found very similar efficiencies of 34% to 61%. Consequently, users can achieve the desired effect with a similar amount of material as when smoking.
In a 2001 study, researchers found that "it is possible to vaporize medically active THC by heating marijuana to a temperature short of the point of combustion, thereby eliminating or substantially reducing harmful smoke toxins that are normally present in marijuana smoke." The unit produced THC at a temperature of 185 °C (365 °F), while eliminating three measured combustion products, benzene
, toluene
and naphthalene
. Carbon monoxide
and smoke tar
s were also reduced, but not quantified.
These positive results are in contrast to MAPS
/NORML's previous studies into vaporizers which found less encouraging results.
A 1996 MAPS study tested two simple vaporizer models, a commercially-available electric hotplate vaporizer and a homemade hot air gun vaporizer, against water pipes and filtered and unfiltered cannabis cigarettes (joint
s). The smoke produced by each was analyzed for solid particulates (tars) and three major cannabinoids. The various ingestion methods were then rated based on their cannabinoid-to-tar ratio. The two tested vaporizers performed up to 25% better than unfiltered cannabis cigarettes (second cleanest) in terms of tar delivery. Both vaporizers produced more than ten times more tars than cannabinoids, though the NIDA-supplied marijuana used had a relatively low THC potency of 2.3%; the authors noted that using higher-quality marijuana or hash oil would have improved the cannabinoid/tar ratio. The same study found that water pipes (bongs) and filtered cigarettes performed 30% worse than regular, unfiltered joints. The reason was that waterpipes and filters filter out psychoactive THC with the tars, thereby requiring users to smoke more to reach their desired effect.
These studies have not measured the presence of toxic gases, such as ammonia
, hydrogen cyanide, and carbon monoxide, though previous studies have indicated unquantified decreases in carbon monoxide with vaporization.
Vaporizers do not completely eliminate respiratory irritation. A large puff of potent, vaporized cannabis will often cause severe coughing. Vaporization systems that utilize water and/or ice for cooling and moisture conditioning by running the vapor through a water pipe or "vaporization water tool" with ice attempt to address the temperature and moisture factor of the delivered vapor to enable larger inhalations without the respiratory irritation that still results from dry-vapor delivery.
Not all those have been scientifically tested. Research using the vaporizer found the delivery efficiency highest at around 226 °C (438.8 °F), falling to about half efficiency at 150 °C (302 °F) to 180 °C (356 °F) degrees depending on material.
The purest preparations produced the highest efficiencies, about 56% for pure THC versus 29% for plant material (female flower tops) with 12% THCA content. Besides THC, several other cannabinoids as well as a range of other plant components including terpenoids were detected in the plant material. Using pure THC in the vaporizer, no degradation products (delta-8-THC (D8-THC), cannabinol (CBN), or unknown compounds) were detected by HPLC
analysis. The longer vapor is stored, the more THC is lost as it condenses on the surface of the vaporizer or the balloon. This loss may be negligible over a few minutes but may exceed 50% after 90 minutes. The Leiden University study found that as much as 30%–40% of inhaled THC was not absorbed by the lungs but simply exhaled. However, they did not find large individual differences in the amounts exhaled.
Inhalation
Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....
the active ingredients of plant material, commonly cannabis
Cannabis (drug)
Cannabis, also known as marijuana among many other names, refers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug or for medicinal purposes. The English term marijuana comes from the Mexican Spanish word marihuana...
, tobacco
Tobacco
Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as a pesticide and, in the form of nicotine tartrate, used in some medicines...
, or other herbs or blends.
Vaporization
Vaporization
Vaporization of an element or compound is a phase transition from the liquid or solid phase to gas phase. There are three types of vaporization: evaporation, boiling and sublimation....
is an alternative to burning
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
(smoking
Smoking
Smoking is a practice in which a substance, most commonly tobacco or cannabis, is burned and the smoke is tasted or inhaled. This is primarily practised as a route of administration for recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them...
) that avoids the production of irritating toxic
Toxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
and carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
ic by-products by heating the material so its active compounds boil off into a vapor
Vapor
A vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....
. No combustion occurs, so no smoke or taste of smoke is present. Vapor ideally contains virtually zero particulate matter or tar
Tar (tobacco residue)
Tar is the common name for the resinous partially combusted and healed particulate matter produced by the burning of tobacco and other plant material in the act of smoking. Tar is purportedly the most destructive component in habitual tobacco smoking, accumulating in the smoker's lungs over time...
, and significantly lower concentrations of noxious gases such as carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
. Vaporizers contain various forms of extraction chambers including straight bore, venturi
Venturi effect
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of pipe. The Venturi effect is named after Giovanni Battista Venturi , an Italian physicist.-Background:...
, or sequential venturi, and are made of materials such as metal or glass. The extracted vapor may be collected in a jar or inflatable bag, or inhaled directly through a hose or pipe. With little to no smoke produced and cooler temperatures, less material is required to achieve a given level of effect. Hence, the irritating and harmful effects of smoking are reduced, as is secondhand smoke
Passive smoking
Passive smoking is the inhalation of smoke, called secondhand smoke or environmental tobacco smoke , from tobacco products used by others. It occurs when tobacco smoke permeates any environment, causing its inhalation by people within that environment. Exposure to secondhand tobacco smoke causes...
.
Classification
Precise vaporizers use an electric heating element, often featuring thermostat
Thermostat
A thermostat is the component of a control system which regulates the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature. The thermostat does this by switching heating or cooling devices on or off, or regulating the flow of a heat transfer...
ic temperature control. High-end models may cost several hundred US dollars.
Broadly, vaporizers may be classified by how they heat the substance:
- By thermal conduction
- By convectionConvectionConvection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....
- By thermal radiationThermal radiationThermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation....
In conduction heating, the substance is placed on a metal plate that is then heated to release the active constituents. Conduction vaporizers were the first type to appear on the market, and are still in production.
In convection heating, the substance never touches a heating element. Instead, hot air passes through it, heating it rapidly, and allowing the release of the active constituents. This method of heating releases more active constituents than conduction heating. Some convection vaporizers or vaporization systems use a hand-held heating wand with a glass-encapsulated element and vortex flow form inducing intakes, which when mated to a bowl on many common pipes or water pipes or when mated to a specialized vaporization chamber bowl, enable the user's draw to pull ambient air past a glass heating surface heating the air prior to its passage through the substrate in the bowl. The vapor is extracted and then passes through the pipe, often with water and/or ice for cooling and conditioning, and thence to the user.
Many convection vaporizers use a long flexible drawtube ("whip") through which the user inhales the vapors, reducing their temperature on arrival. Some vaporizers have a bag or balloon attachment; vapor is blown into the bag, and the user detaches the bag and inhales the contents. Attachments can be placed between the vaporizer or bag and the user's mouth to cool the vapor with water or ice.
Convection vaporizers are either forced-air types which actively blow air through the heating element and herbs, or passive types, where the user inhales the air without the help of a fan or pump. Most vaporizers today use the convection principle, including heat guns, "wood box" types, and nearly every higher-end vaporizer available.
In radiation heating, the substance absorbs radiant energy and its temperature rises. The energy can be provided by a superheated thermal mass placed around it, or from a visible bright light source like the sun. Thermal mass radiation vaporizers permit uniform heating of substate without diluting vapours, supplying high quality medicine. A pipe and a magnifying glass on a bright, sunny day can, with care and practice, act as an adequate radiation vaporizer.
Vapor quality
Few vaporizer studies or reviews have really addressed the quality of the vapor extracted and delivered; instead, focus has generally been on the mode of usage of the vaporizer. There are at least 60 pharmacologically-active compounds in cannabis. The aromatic terpenoids begin to vaporize at 126°C, but the more bio-active cannabidiol (CBD)Cannabidiol
Cannabidiol is a cannabinoid found in Cannabis. It is a major constituent of the plant, representing up to 40% in its extracts.It has displayed sedative effects in animal tests...
, Cannabinol (CBN)
Cannabinol
Cannabinol is a psychoactive substance cannabinoid found in Cannabis sativa and Cannabis indica/afghanica. It is also a metabolite of tetrahydrocannabinol . CBN acts as a weak agonist of the CB1 and CB2 receptors, with lower affinity in comparison to THC.- External links :* Compounds found in...
, and delta-9-tetrahydrocannabinol (THC)
THC
THC commonly refers to tetrahydrocannabinol, the main active chemical compound in Cannabis.THC may also refer to:* Tan Holdings Corporation...
do not vaporize until near their respective flash point
Flash point
The flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source...
s: CBD 206.3°C, CBN 212.7°C,and THC 149.3°C. Because most commercial vaporizers are slow in extraction and delivery, the vapor inhaled is first aromatic, but only minimally active; as the plant material temperature rises, the vapor becomes increasingly bio-active, but minimally aromatic, because most of the aromatics have already been released. This problem is addressed in the modular vaporization tool-based systems by use of a sequential venturi effect for more rapid extractions via a vaporization chamber bowl and vaporization heat wand or heat gun and is addressed in some box vaporizers by way of a venturi-inducing extraction intake prior to the hose. With the vaporization chamber bowl approach, many common pipes can be modified, enabling the delivery of broader-spectrum vapor preferred by many users and higher in concentration, consistency, and aromatic density due to the increased rate of extraction and smaller sample size. Bag capture vaporizers tend to be slower in extraction rate, which prevents the attainment of fuller spectrum vapor, but are more convenient to use.
Scientific study
Studies have shown that vaporizing cannabis exposes the user to lower levels of harmful substances than smoking cannabis. Substantial reductions were also found for the M1-volatizer.In 2007 a study by University of California, San Francisco
University of California, San Francisco
The University of California, San Francisco is one of the world's leading centers of health sciences research, patient care, and education. UCSF's medical, pharmacy, dentistry, nursing, and graduate schools are among the top health science professional schools in the world...
published in the Journal of the American Academy of Neurology examined the efficacy of a vaporizer that heats cannabis to a temperature between 180 °C (356 °F) and 200 °C (392 °F) degrees and found:
In 2006 a study performed by researchers at Leiden University
Leiden University
Leiden University , located in the city of Leiden, is the oldest university in the Netherlands. The university was founded in 1575 by William, Prince of Orange, leader of the Dutch Revolt in the Eighty Years' War. The royal Dutch House of Orange-Nassau and Leiden University still have a close...
tested a vaporizer with preparations of pure THC and found that:
When using plant material (crude flower tops), besides THC, several other cannabinoids and a range of other plant components including terpenoids
Terpene
Terpenes are a large and diverse class of organic compounds, produced by a variety of plants, particularly conifers, though also by some insects such as termites or swallowtail butterflies, which emit terpenes from their osmeterium. They are often strong smelling and thus may have had a protective...
were detected in the plant material. However, using pure THC in the vaporizer, no degradation products (D8-THC
Tetrahydrocannabinol
Tetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...
, CBN
Cannabinol
Cannabinol is a psychoactive substance cannabinoid found in Cannabis sativa and Cannabis indica/afghanica. It is also a metabolite of tetrahydrocannabinol . CBN acts as a weak agonist of the CB1 and CB2 receptors, with lower affinity in comparison to THC.- External links :* Compounds found in...
, or unknown compounds) were detected by HPLC
High performance liquid chromatography
High-performance liquid chromatography , HPLC, is a chromatographic technique that can separate a mixture of compounds and is used in biochemistry and analytical chemistry to identify, quantify and purify the individual components of the mixture.HPLC typically utilizes different types of stationary...
analysis. Also, a substantially larger fraction of the THC was delivered to the vapor by using pure THC.
Analysis of the vapor from the vaporizer found that using multiple passes it delivered 36%–61% of the THC in the sample. A study using pure cannabinoid preparations achieved a maximum of 54%. Studies of cannabis cigarettes smoked via a smoking machine under varying conditions of puff duration and air speed found very similar efficiencies of 34% to 61%. Consequently, users can achieve the desired effect with a similar amount of material as when smoking.
In a 2001 study, researchers found that "it is possible to vaporize medically active THC by heating marijuana to a temperature short of the point of combustion, thereby eliminating or substantially reducing harmful smoke toxins that are normally present in marijuana smoke." The unit produced THC at a temperature of 185 °C (365 °F), while eliminating three measured combustion products, benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
, toluene
Toluene
Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. It is a mono-substituted benzene derivative, i.e., one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3.It is an aromatic...
and naphthalene
Naphthalene
Naphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...
. Carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
and smoke tar
Tar
Tar is modified pitch produced primarily from the wood and roots of pine by destructive distillation under pyrolysis. Production and trade in tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden vessels against rot. The largest...
s were also reduced, but not quantified.
These positive results are in contrast to MAPS
Multidisciplinary Association for Psychedelic Studies
The Multidisciplinary Association for Psychedelic Studies is a membership-based 501 non-profit research and educational organization working to develop psychedelics and marijuana into legal prescription drugs...
/NORML's previous studies into vaporizers which found less encouraging results.
A 1996 MAPS study tested two simple vaporizer models, a commercially-available electric hotplate vaporizer and a homemade hot air gun vaporizer, against water pipes and filtered and unfiltered cannabis cigarettes (joint
Joint (cannabis)
Joint is a slang term for a cigarette rolled using cannabis. Rolling papers are the most common rolling medium among industrialized countries, however brown paper, cigarettes with the tobacco removed, and newspaper are commonly used in developing countries. Modern papers are now made from a wide...
s). The smoke produced by each was analyzed for solid particulates (tars) and three major cannabinoids. The various ingestion methods were then rated based on their cannabinoid-to-tar ratio. The two tested vaporizers performed up to 25% better than unfiltered cannabis cigarettes (second cleanest) in terms of tar delivery. Both vaporizers produced more than ten times more tars than cannabinoids, though the NIDA-supplied marijuana used had a relatively low THC potency of 2.3%; the authors noted that using higher-quality marijuana or hash oil would have improved the cannabinoid/tar ratio. The same study found that water pipes (bongs) and filtered cigarettes performed 30% worse than regular, unfiltered joints. The reason was that waterpipes and filters filter out psychoactive THC with the tars, thereby requiring users to smoke more to reach their desired effect.
These studies have not measured the presence of toxic gases, such as ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, hydrogen cyanide, and carbon monoxide, though previous studies have indicated unquantified decreases in carbon monoxide with vaporization.
Vaporizers do not completely eliminate respiratory irritation. A large puff of potent, vaporized cannabis will often cause severe coughing. Vaporization systems that utilize water and/or ice for cooling and moisture conditioning by running the vapor through a water pipe or "vaporization water tool" with ice attempt to address the temperature and moisture factor of the delivered vapor to enable larger inhalations without the respiratory irritation that still results from dry-vapor delivery.
Efficiency
Proposed factors affecting output include:- Temperature
- Specimen densityDensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
- Weight, content of water and essential oilEssential oilAn essential oil is a concentrated hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile oils, ethereal oils or aetherolea, or simply as the "oil of" the plant from which they were extracted, such as oil of clove...
s - Consistency of material in the filling chamber
- Variety and potency of cannabis used
- Different preparations such as crude flower tops, hashishHashishHashish is a cannabis preparation composed of compressed stalked resin glands, called trichomes, collected from the unfertilized buds of the cannabis plant. It contains the same active ingredients but in higher concentrations than unsifted buds or leaves...
, hash oilHash oilHash oil is a resinous matrix of cannabinoids produced by a solvent extraction of cannabis. Hash oil is a concentrated product with a high THC content, which generally varies between 70% and 90%. Related honey oil is a specific type of hash oil made from the more potent parts of the cannabis plant...
, etc. - Storage time of the vapor
- Proportion of THC exhaled (breathing technique)
Not all those have been scientifically tested. Research using the vaporizer found the delivery efficiency highest at around 226 °C (438.8 °F), falling to about half efficiency at 150 °C (302 °F) to 180 °C (356 °F) degrees depending on material.
The purest preparations produced the highest efficiencies, about 56% for pure THC versus 29% for plant material (female flower tops) with 12% THCA content. Besides THC, several other cannabinoids as well as a range of other plant components including terpenoids were detected in the plant material. Using pure THC in the vaporizer, no degradation products (delta-8-THC (D8-THC), cannabinol (CBN), or unknown compounds) were detected by HPLC
High-performance liquid chromatography
High-performance liquid chromatography , HPLC, is a chromatographic technique that can separate a mixture of compounds and is used in biochemistry and analytical chemistry to identify, quantify and purify the individual components of the mixture.HPLC typically utilizes different types of stationary...
analysis. The longer vapor is stored, the more THC is lost as it condenses on the surface of the vaporizer or the balloon. This loss may be negligible over a few minutes but may exceed 50% after 90 minutes. The Leiden University study found that as much as 30%–40% of inhaled THC was not absorbed by the lungs but simply exhaled. However, they did not find large individual differences in the amounts exhaled.