Acrolein
Smells like burnt fat — acts like a chemical weapon.
At a glance
- Also known as
- 2-Propenal · Acrylaldehyd
- CAS number
- 107-02-8
- Toxicity
Very high
- Carcinogenic
- Yes — IARC Group 2A
- In cigarette smoke
- 50-150 μg per cigarette (DKFZ)
- In vape aerosol
- 10-200 μg per puff at high wattage (Sleiman et al., Env Sci Technol 2016)
What is Acrolein?
Acrolein is the simplest unsaturated aldehyde and one of the most reactive substances in cigarette and vape smoke. It forms when fats, glycerol and plant oils are heated above about 280 °C. The IARC upgraded acrolein in 2021 to „probably carcinogenic to humans“ (Group 2A).
Why is Acrolein in cigarettes?
When tobacco burns, plant oils and sugars oxidise to short-chain aldehydes — acrolein is one of the most important alongside formaldehyde and acetaldehyde. Each cigarette delivers 50 to 150 micrograms of acrolein into the mainstream smoke (source: DKFZ). In vapes, acrolein forms as soon as the coil heats vegetable glycerin (VG) above 280 °C — at high wattages or in so-called „dry hits“.
What Acrolein does to your body — short term
Acrolein is one of the strongest airway irritants in tobacco smoke. Even small concentrations irritate the mucous membranes of eyes and upper airways; the characteristic burn when deeply inhaling a cigarette is largely due to acrolein. Higher amounts trigger violent coughing, tearing and shortness of breath — a reaction against which the body has almost no protective option.
What Acrolein does long term
Chronic acrolein exposure damages the bronchial mucosa at the cellular level and is considered one of the most important drivers of COPD in smokers. Acrolein also impairs DNA-repair mechanisms, amplifying the carcinogenic effect of other compounds. The IARC's 2021 upgrade rests on evidence from lung and airway cancer studies. Research also discusses a link to cardiovascular disease.
Where else do you know Acrolein from?
Acrolein is used industrially as a herbicide — under the trade name „Magnacide H“ for algae control in irrigation canals. In World War 1, acrolein was tested as a chemical warfare agent; its extreme irritant character made it an experimental tear and lung poison. You recognise the smell of acrolein when cooking oil in the pan starts to smoke.
How it compares
Germany's DFG no longer publishes a fixed MAK value for acrolein, since the data on its carcinogenic effect is considered insufficient for a safe concentration limit; ACGIH recommends a ceiling value of 0.23 mg/m³ (0.1 ppm). A pack-a-day smoker takes in roughly 2 milligrams of acrolein from smoke daily — directly into the airways, in short highly-concentrated bursts, without the dilution in an open room that any workplace limit assumes.
Workplace exposure limit: 0.23 mg/m³ (0.1 ppm Ceiling, ACGIH TLV-C)
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