UC Riverside researchers find e-cigarette aerosol decreases over time in smoke-out interval, requiring stronger puffs
Stronger suction is required to smoke "electronic cigarettes" - marketed as tobacco-free nicotine delivery systems - than conventional brands, with possible adverse effects on human health, researchers at the University of California, Riverside report.
The researchers used a smoking machine to compare the smoking properties of eight conventional cigarettes with five e-cigarette brands. They examined the vacuum required to produce smoke (in the case of conventional cigarettes) or aerosol (in the case of e-cigarettes), and compared the density of the smoke/aerosol over time.
The researchers found that except for one brand (Liberty Stix), higher vacuums were required to smoke e-cigarettes than conventional brands.
The researchers also found that in the case of e-cigarettes, the aerosol density dropped after the first ten puffs, requiring still stronger suction thereafter to produce aerosol.
Study results appeared last week in Nicotine and Tobacco Research.
"It is too early to know exactly what effect stronger inhaling and diminishing amounts of aerosol will have on human health, but these factors are likely to lead to compensatory smoking, as has been seen previously with 'light' tobacco cigarettes," said Prue Talbot, a professor of cell biology and the senior author of the research paper.
Talbot's research team examined the following conventional cigarettes: Merit Ultra Lights, Marlboro Ultra Lights, Marlboro Lights, Marlboro Reds, Camel unfiltered, Camel Lights, Camel filtered, and Pall Mall unfiltered cigarettes. In the case of e-cigarettes, the researchers tested the following kits: Liberty Stix, Crown Seven's Hydro Kit, NJOY, Smoking Everywhere's Gold Kit, and a VapCigs starter kit.
"Our work shows that aerosol density decreases as e-cigarettes are used, requiring stronger puffs over time to sustain density," Talbot said. "Manufacturers often claim that e-cigarettes cartridges are equivalent to a certain number of conventional cigarettes. However, this information seems misleading."
Talbot's lab found that while the first ten puffs of an e-cigarette are similar to a conventional cigarette, later puffs were highly variable in aerosol density and do not duplicate smoking of conventional brands. The researchers found that even though one e-cigarette cartridge may smoke for 200 puffs, cartridges do not smoke uniformly for those 200 puffs and therefore do not duplicate nicotine delivery of individual conventional cigarettes.