- Vapes cut toxic chemical exposure by up to 98 per cent, including major carcinogens
- Heated tobacco products (HTPs) reduce harmful substances by up to 91 per cent
- Some emissions in vapes and HTPs fall below detectable limits
- Alternatives are not harmless, but offer a less harmful option for smokers who can’t quit
Heated tobacco products (HTPs) and vapes reduce exposure to harmful chemicals by more than 90 per cent compared to cigarettes, according to a major new study.
Published in the International Journal of Environmental Research and Public Health, the peer-reviewed analysis compared emissions from combustible cigarettes, HTPs, and vapes.
Drawing on real-world data from 15 independent studies, the review found HTPs and vapes cut exposure to toxic substances by up to 91 per cent and 98 per cent per puff, respectively.
It said: “Based on the analysis of the latest independent studies’ empirical data, the concentrations of inhaled HPHCs using heated tobacco products or e-cigarettes are reduced up to 91–98 per cent, respectively; therefore, for those who cannot quit, these could provide a less harmful alternative.”
This large-scale review is among the most comprehensive to date, including only studies that used validated testing methods and excluding any with ties to the tobacco industry.
Why smoking is so harmful
Combustible cigarettes burn at over 500°C, releasing more than 7,000 chemicals – around 100 of which are classified by health authorities as harmful or potentially harmful.
These include well-known carcinogens like polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific nitrosamines (TSNAs), as well as volatile organic compounds (VOCs), carbonyls, and carbon monoxide.
“Combustion-based products are the ones most harmful to smokers,” the study said.
By contrast, HTPs heat real tobacco at lower temperatures (below 400°C) without combustion. This significantly reduces the formation of toxic substances. Vapes, meanwhile, work differently: they vaporise a liquid containing nicotine, propylene glycol, glycerol, and flavourings, without burning tobacco at all.
What the data shows
To compare products accurately, the researchers standardised chemical emission data by converting all measurements to a per-puff basis. The analysis found:
- PAHs (potent carcinogens): reduced by 96 per cent in HTPs, 99 per cent in vapes
- VOCs (volatile organic compounds): reduced by 99 per cent in HTPs, 100 per cent in vapes
- Carbonyls (e.g. formaldehyde, acetaldehyde): down 65 – 95 per cent in HTPs, nearly eliminated in vapes
- TSNAs (tobacco-specific nitrosamines): down 89 – 94 per cent in HTPs, 99 per cent in vapes
- Carbon monoxide: reduced by 98 per cent in HTPs, 99 per cent in vapes
In many cases, chemical levels in HTP and vape emissions were below detectable limits, suggesting near-total elimination of some toxicants compared to cigarette smoke.
The authors also found that levels of toxic metals such as lead and cadmium – often a concern with heated or vapourised products – were significantly lower in vapes and HTPs than in cigarettes.
A less harmful alternative
The study’s authors stress that while vapes and HTPs are not risk-free, they are clearly much less harmful than smoking. For adult smokers who are unable or unwilling to quit nicotine altogether, switching to a smoke-free product could substantially reduce health risks.
“Such a significant reduction in HPHCs results in a reduced exposure to toxic substances, which in turn leads to fewer adverse health effects for smokers,” the study said.
The paper does not advocate these products for non-smokers, and reinforces that the best option for health is to quit all nicotine use entirely. However, it supports the role of alternative products in harm reduction strategies, particularly for countries where smoking rates remain high and access to cessation services is limited.
No combustion = fewer toxic substances
The authors note that because both HTPs and vapes avoid combustion, they inherently produce far fewer toxic substances than conventional cigarettes. The combination of significantly lower levels of known carcinogens, reduced respiratory irritants, and sharply diminished carbon monoxide exposure supports their classification as “less harmful alternatives.”
The review adds to a growing body of independent evidence that switching to smoke-free products can dramatically reduce a smoker’s exposure to the chemicals most closely linked to cancer, heart disease, and other tobacco-related illnesses.
