Difference between vapor and smoke
Pro Research Analysisby 
Searched over 200M research papers
Definitions and Key Differences: Vapor vs. Smoke
Vapor and smoke are both aerosols, but they are produced and composed differently. Smoke is created by burning a substance, such as tobacco or cannabis, which leads to combustion and the release of thousands of chemicals, many of which are toxic or carcinogenic. In contrast, vapor is produced by heating a liquid or plant material to a temperature below combustion, resulting in an aerosol that contains fewer harmful chemicals Anthérieu2017Takahashi2018Shen2016.
Chemical Composition: Smoke Contains More Harmful Substances
Cigarette smoke contains high levels of toxic compounds, including carbon monoxide, tar, and a range of carcinogens known as "Hoffmann analytes." These substances are produced during combustion and are responsible for much of the harm associated with smoking . Vapor, whether from e-cigarettes or vaporized cannabis, contains significantly lower levels of these harmful chemicals, as the process does not involve burning and typically occurs at much lower temperatures Takahashi2018Anthérieu2017.
Health Effects: Lower Toxicity in Vapor Compared to Smoke
Studies comparing the effects of vapor and smoke on human cells and animal models consistently show that vapor is less toxic. Cigarette smoke causes significant cell death, oxidative stress, inflammation, and changes in gene expression related to disease in human bronchial epithelial cells, while e-cigarette vapor causes much milder effects Anthérieu2017Shen2016. Similarly, in animal studies, exposure to cigarette smoke leads to more severe cardiovascular and respiratory problems, such as atherosclerosis, lung inflammation, and emphysema, compared to vapor exposure, which results in substantially lower biological and pathological changes Szostak2020Wong2021.
Subjective and Physiological Effects: Differences in Exposure
When comparing smoked and vaporized cannabis, both methods produce similar subjective effects, but smoking leads to higher carbon monoxide exposure, a marker of combustion and a known health risk . Vaporization delivers the active compounds efficiently but with less exposure to harmful byproducts of combustion Newmeyer2017Spindle2019.
Molecular and Cellular Responses: Distinct Gene Expression Profiles
Smoke and vapor also trigger different responses at the molecular level. Cigarette smoke causes widespread changes in gene expression related to cell death, oxidative stress, and inflammation, while vapor exposure leads to more limited and specific changes, often related to lipid metabolism and, when nicotine is present, to nicotine processing pathways Anthérieu2017Shen2016.
Conclusion
In summary, the main difference between vapor and smoke lies in their method of production and resulting chemical composition. Smoke is produced by combustion and contains many harmful chemicals, while vapor is generated by heating without burning, resulting in fewer toxic substances. Health studies consistently show that vapor is less harmful than smoke, causing less toxicity, inflammation, and cellular damage. However, vapor is not completely harmless and can still affect biological pathways, especially when nicotine or other additives are present Anthérieu2017Szostak2020Wong2021+2 MORE.
Sources and full results
Most relevant research papers on this topic
Comparison of cellular and transcriptomic effects between electronic cigarette vapor and cigarette smoke in human bronchial epithelial cells.
Electronic cigarette vapor shows lower toxicity compared to cigarette smoke in human bronchial epithelial cells.
Subjective and physiological effects, and expired carbon monoxide concentrations in frequent and occasional cannabis smokers following smoked, vaporized, and oral cannabis administration.
Smoking and vaporizing cannabis significantly increase subjective effects, while oral cannabis only affects occasional smokers, indicating partial tolerance with frequent exposure.
Chemical analysis and in vitro toxicological evaluation of aerosol from a novel tobacco vapor product: A comparison with cigarette smoke
The aerosol from a novel tobacco vapor product (NTV) has a significantly lower toxicological profile compared to cigarette smoke, with no measurable genotoxicity or cytotoxicity.
Acute Pharmacokinetic Profile of Smoked and Vaporized Cannabis in Human Blood and Oral Fluid.
Vaporization is a more efficient method of delivering cannabis to the blood and oral fluid compared to smoking, with higher THC concentrations in blood and longer THC detection in oral fluid.
Different physiological and behavioural effects of e-cigarette vapour and cigarette smoke in mice.
E-cigarette vapour and cigarette smoke both cause addiction-related neurochemical, physiological, and behavioral alterations, but their effects vary, suggesting compounds other than nicotine contribute to tobacco dependence.
DOI