Chemical emissions from heat-not-burn tobacco devices are lower than from conventional cigarettes, but they’re still high enough to be cause for concern, US government researchers report.
The makers of such devices claim that they produce a “clean” vapour that contains fewer irritants and cancer-causing chemicals than a traditional cigarette, and are therefore less dangerous.
“We found that the emissions from a widely used heat-not-burn device are not negligible,” said first study author Lucia Cancelada, a former affiliate researcher in the US department of energy’s Lawrence Berkeley Lab‘s Indoor Environment Group. “These products are engineered so that it looks like hardly anything comes out of them; but just because the emissions are minimal doesn’t mean they don’t exist,” Cancelada explained in a lab news release.
The team tested a battery-powered device that’s sold in about 43 countries. It’s not yet available in the US, but it was approved by the US Food and Drug Administration earlier this year.
The device has a cigar-shaped electronic holder. A tobacco “heat stick” that resembles a short, thin cigarette and contains processed tobacco, glycerin and other additives is inserted into the holder, and a button is pressed to activate the heater.
The interior of the stick heats to between 180 and 220 degrees Celsius (356 to 428 Fahrenheit). The nicotine and other chemicals evaporate, rather than burn, and are inhaled through the filter in the mouthpiece as an aerosol.
In the study, the researchers assessed levels of chemicals in the aerosol inhaled by the user and aerosolized chemicals emitted by the device that are not inhaled by the user, akin to second-hand smoke from tobacco cigarettes.
Levels from the heat-not-burn device are similar to those produced by electronic cigarettes, according to the study.
Hugo Destaillats is a chemist in Berkeley Lab‘s Energy Technologies Area and deputy of the Indoor Environment Group. He said, “Heat-not-burn products, just like electronic cigarettes, emit aerosols – mixtures of gases and particles. In the case of electronic cigarettes, calling these emissions vapor is genius marketing, but misleading, because users may think they emit water vapor, making it less harmful in their minds.”
But, Destaillats explained, “neither e-cigarette refill liquids and cartridges, nor heat sticks, are water-based. Most contain a large amount of glycerin, and our previous research has shown that heat-driven breakdown of glycerin is a source of harmful chemicals.”
This study characterized emissions from IQOS, a heated tobacco product promoted as a less harmful alternative to cigarettes. Consumable tobacco plugs were analyzed by headspace GC/MS to assess the influence of heating temperature on the emission profile. Yields of major chemical constituents increased from 4.1 mg per unit at 180 °C to 6.2 mg at 200 °C, and 10.5 mg at 220 °C. The Health Canada Intense smoking regime was used to operate IQOS in an environmental chamber, quantifying 33 volatile organic compounds in mainstream and sidestream emissions.
Aldehydes, nitrogenated species, and aromatic species were found, along with other harmful and potentially harmful compounds. Compared with combustion cigarettes, IQOS yields were in most cases 1–2 orders of magnitude lower. However, yields were closer to, and sometimes higher than electronic cigarettes. Predicted users’ daily average intake of benzene, formaldehyde, acetaldehyde and acrolein were 39 μg, 32 μg, 2.2 mg and 71 μg, respectively. Indoor air concentrations were estimated for commonly encountered scenarios, with acrolein levels of concern (over 0.35 μg m–3) derived from IQOS used in homes and public spaces. Heated tobacco products are a weaker indoor pollution source than conventional cigarettes, but their impacts are neither negligible nor yet fully understood.
Lucia Cancelada, Mohamad Sleiman, Xiaochen Tang, Marion L Russell, V Nahuel Montesinos, Marta I Litter, Lara A Gundel, Hugo Destaillats