Vaporization vs. Combustion in Cannabis

Understanding the Health Impacts of Cannabis Consumption

Cannabis can be consumed in many ways, but two of the most common methods are smoking (which is combustion) and vaporization. Emerging research shows that the method of consumption significantly impacts the chemical compounds you inhale and the associated health risks.

Why Vaporization Reduces Harmful Byproducts

Combusting cannabis has been found to produce undesired toxic by-products, such as carcinogenic polynuclear aromatic hydrocarbons (PAHs), benzene, and toluene, as well as carbon monoxide (CO). These toxic byproducts are never made while vaping because the bud never reaches the temperature required to make them. Vaporizing draws heated air through the bud to produce the smoke, drawing all the good stuff (cannabinoids) along with the hot vapor. Using a lighter or torch on your bud puts that flame right onto the plant material, resulting in those high temperatures capable of producing all the byproducts. Bypassing the inhalation of those byproducts by vaping significantly lowers the risk of respiratory hazards compared with smoking cannabis.

Polynuclear Aromatic Hydrocarbons (PAHs)

  • Origin: Formed when organic material like cannabis burns at high temperatures (~300–400°C / 572–752°F).

  • Mechanism: Carbon in the plant reorganizes under extreme heat, creating multi-ringed molecules.

  • Health Concern: Many PAHs are carcinogenic and can damage DNA in lung cells over time.

Benzene & Toluene

  • Origin: Produced from incomplete combustion of plant matter or residual solvents in improperly processed cannabis.

  • Mechanism: As cannabis burns, cellulose and other organic compounds break down into volatile aromatic hydrocarbons.

  • Health Concern: Both benzene and toluene are toxic to humans, affecting the lungs, nervous system, and increasing long-term cancer risk.

Carbon Monoxide (CO)

  • Origin: Generated whenever carbon-containing material is burned in a low-oxygen environment.

  • Mechanism: Burning cannabis produces CO because oxygen is insufficient to fully convert carbon to CO₂.

  • Health Concern: CO binds to hemoglobin in the blood, reducing oxygen transport. This can lead to dizziness, shortness of breath, or serious cardiovascular issues.

None of these harmful compounds are inherently in raw cannabis - they are by-products of burning. Vaporization, which heats the plant without burning, avoids most of them.

 

Evidence from Human Studies

A cross-sectional study found that vaporizer users were 40% less likely to report respiratory symptoms such as cough, phlegm, and chest tightness compared to cannabis smokers, even after controlling for cigarette use and total cannabis consumption.

Laboratory experiments comparing vaporized versus combusted cannabis show that:

  • Vapor: Composed overwhelmingly of cannabinoids with virtually no pyrolytic compounds. Only trace amounts of caryophyllene (a terpene) and two other unknown compounds were detected.

  • Smoke: Contained 111 detectable compounds, including multiple known PAHs. The cannabinoid ratio was much lower (12% of total mass compared with 94.8% in vapor).

Exhaled CO measurements further confirmed the difference. Smoking cannabis produced large increases in CO, while vaporization produced little to no increase. Additionally, ammonia levels were significantly higher in smoked cannabis than in vaporized samples (70 ppm vs. 6 ppm), which has implications for respiratory safety in clinical settings.

 

Hazard Index and Excess Lifetime Cancer Risk

Risk modeling provides additional clarity on the differences between smoking, dabbing, and vaping at various voltages. The Hazard Index (HI) measures whether exposure levels exceed safe thresholds (values greater than 1 indicate potential health risks), while the Excess Lifetime Cancer Risk (ELCR) estimates the probability of developing cancer from long-term use.

Consumption Type

HI Value

What It Means

ELCR Value

What It Means

Smoking (flower)

2 × 10² (200)

Extremely high exposure above safe level. Big red flag for chronic toxicity.

4 × 10⁻⁴

About 4 in 10,000 extra lifetime cancer risk—above most safety thresholds.

Dabbing (distillate)

2 × 10⁻¹ (0.2)

Below 1, so generally within safe exposure.

2 × 10⁻⁷

1 in ~5 million cancer risk—negligible.

Vaping @ 4.8 V

4 × 10⁻² (0.04)

Still well below 1, safer exposure.

2 × 10⁻⁷

Very low cancer risk.

Vaping @ 4.0 V

6 × 10⁻³ (0.006)

Even lower risk.

2 × 10⁻⁸

1 in 50 million risk.

Vaping @ 3.2 V

8 × 10⁻⁴ (0.0008)

Virtually negligible exposure.

2 × 10⁻⁹

1 in 500 million cancer risk.

These results highlight just how different the risks are across methods of consumption:

  • Smoking flower poses the greatest hazard, with an HI far above safe levels (200) and a cancer risk of 4 in 10,000—higher than most accepted thresholds.

  • Dabbing distillate dramatically reduces risk, staying well below hazardous exposure levels with negligible cancer probability.

  • Vaping distillate is the lowest-risk method, especially at lower voltages. At 3.2 volts, the hazard index and cancer risk are nearly negligible.

 

Risks of Vaping Products

While vaporization of pure flower is generally safer than smoking, some commercial vaping products carry additional risks:

1. Respiratory Irritation

Even when vaping pure cannabis flower, inhaling hot vapor can irritate the lungs and airways. Symptoms may include coughing, throat irritation, or a feeling of tightness in the chest, especially with frequent use.

2. Thermal Degradation Products

When dry herb is heated:

Some cannabinoids and terpenes can break down into formaldehyde, acrolein, or benzene, especially at high temperatures (>392–428°F).

These compounds are toxic and potentially carcinogenic, though at lower levels than smoking.

3. Heavy Metal Exposure

Even in dry herb vaporizers, heating elements (often metal or ceramic) can leach trace metals like nickel, chromium, or lead into vapor over time. This risk increases with cheaper or poorly maintained devices.

4. Ultrafine Particles

Vapor contains very small particles that can penetrate deep into the lungs. While less harmful than smoke, these ultrafine particulates may still contribute to inflammation or long-term lung stress.

Use only high-quality, well-cured flower: Only use cannabis from trusted sources that test for pesticides, mold, and heavy metals. Poor-quality or contaminated flower can release harmful compounds when heated.

Temperature control: Using a vaporizer at recommended temperatures (generally 320–428°F) minimizes the formation of harmful compounds while preserving beneficial cannabinoids and terpenes.

 

Conclusion

Vaporization offers a safer alternative to smoking cannabis by:

  1. Delivering cannabinoids efficiently, lower dosage needed to produce desired effects.

  2. Reducing exposure to carbon monoxide and toxic pyrolytic by-products.

  3. Minimizing respiratory irritation and long-term lung risk.

However, the safety benefits are only realized when using clean, well-made vaporizer devices and avoiding unregulated or adulterated products. Laboratory and clinical studies confirm that vaporizing pure cannabis provides high cannabinoid delivery while significantly lowering harmful emissions, making it the preferred method for both recreational and medicinal users seeking a healthier consumption method.

Our Flower Vaporizer Pick:

PAX Flow | $300.00 | Trichly

 

 

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