Vapes do produce small amounts of carbon monoxide, though far less than traditional cigarettes. Lab measurements using sensitive laser spectroscopy have detected carbon monoxide in e-cigarette aerosol at levels between 1 and 9.5 parts per million (ppm). That’s a fraction of what a combustible cigarette produces, which delivers roughly 15 mg of carbon monoxide per cigarette in mainstream smoke alone, with an additional 50 mg released as sidestream smoke into the surrounding air.
The short answer is that vaping isn’t carbon monoxide-free, but the amount varies dramatically depending on the device, the power setting, and how it’s used.
Why Vapes Produce Any Carbon Monoxide at All
Carbon monoxide is most commonly associated with burning things. When tobacco combusts in a cigarette, incomplete burning of organic material generates large quantities of the gas. Vapes don’t combust anything, which is why many people assume they’re completely free of carbon monoxide. But heating e-liquid to high temperatures can thermally break down its ingredients, particularly the propylene glycol, vegetable glycerin, and flavoring compounds. This thermal decomposition produces trace amounts of carbon monoxide even without a flame.
Research published in the International Journal of Environmental Research and Public Health confirmed that carbon monoxide in e-cigarette aerosol is produced by thermal decomposition of e-liquid components, not combustion. The same process also generates aldehydes, and the two tend to rise and fall together. Higher coil temperatures mean more breakdown of the liquid’s chemical bonds, which means more carbon monoxide in each puff.
How Power and Temperature Change the Numbers
The single biggest factor in how much carbon monoxide a vape produces is the power running through the coil. Researchers found a clear, linear relationship: as wattage increases, carbon monoxide emissions climb in a predictable pattern. For a flavored e-liquid, emissions rose by about 0.057 micrograms per puff for every additional watt of power. Unflavored liquid produced less, increasing by 0.014 micrograms per puff per watt.
This means a low-power pod system running at 10 or 15 watts produces significantly less carbon monoxide than a sub-ohm device cranked up to 80 or 100 watts. Flavored liquids consistently generate more than unflavored ones at the same wattage, likely because the additional flavoring chemicals provide more material for thermal breakdown.
Dry hits, where the wick runs low on liquid and the cotton itself begins to scorch, can spike emissions further. When the coil heats dry cotton rather than saturated e-liquid, the conditions move closer to actual combustion, which increases carbon monoxide and other harmful byproducts substantially.
Vaping vs. Smoking: The Scale of Difference
To put the numbers in perspective, a single conventional cigarette delivers about 15 mg of carbon monoxide to the smoker. The trace amounts detected in e-cigarette aerosol, measured in micrograms per puff, are orders of magnitude lower under normal use. Cannabis vaporizers show a similar pattern. Research comparing smoked and vaporized cannabis found that vaporizing significantly reduces exposure to carbon monoxide and avoids producing many of the carcinogenic compounds created by combustion.
For context on safety thresholds, the World Health Organization sets indoor air quality guidelines for carbon monoxide at 10 mg per cubic meter over 8 hours and 7 mg per cubic meter over 24 hours. Normal vaping under typical conditions produces carbon monoxide levels well below these limits, while cigarette smoking easily exceeds them.
Carbon Monoxide in the Blood
The body’s standard measure of carbon monoxide exposure is carboxyhemoglobin, the percentage of hemoglobin in your blood that’s bound to carbon monoxide instead of oxygen. Normal levels sit between 3% and 5%. Most vapers don’t show meaningfully elevated carboxyhemoglobin compared to non-smokers.
However, extreme cases exist. A published case report documented a patient whose carboxyhemoglobin levels ranged from 7.1% to 32.9% due to heavy vaping. Those levels were both higher and slower to resolve than levels seen in 12 cigarette smokers tested for comparison. The patient required targeted oxygen therapy, and her levels took an average of 47 hours to return to normal. This case involved unusually heavy use combined with pre-existing lung disease, but it demonstrates that intense, prolonged vaping sessions can push carbon monoxide exposure into a clinically significant range.
What Actually Affects Your Exposure
Several practical factors determine how much carbon monoxide you’re exposed to while vaping:
- Wattage: Higher power means higher coil temperatures and more thermal decomposition. Keeping your device at the lower end of the recommended range for your coil reduces emissions.
- E-liquid type: Flavored liquids produce roughly four times more carbon monoxide per watt increase than unflavored liquids, based on the available data.
- Puff frequency and duration: Chain vaping increases cumulative exposure. Longer draws at high power compound the effect.
- Wick saturation: Dry or semi-dry hits from a low tank or an old coil push temperatures higher and bring conditions closer to combustion. If you taste a burnt flavor, your device is producing elevated levels of carbon monoxide and other harmful compounds.
The bottom line is that vapes are not carbon monoxide-free, but under normal conditions the amounts are a tiny fraction of what cigarettes produce. The risk increases meaningfully with high-wattage devices, flavored liquids, and especially dry hits. If you’re switching from cigarettes, the reduction in carbon monoxide exposure is one of the more straightforward health improvements. If you’ve never smoked, those trace amounts represent an avoidable exposure that wouldn’t otherwise be there.