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Effect of Charcoal in Cigarette Filters on Free Radicals in Mainstream Smoke
journal contribution
posted on 2018-07-06, 00:00 authored by Reema Goel, Zachary T. Bitzer, Samantha M. Reilly, Gurkirat Bhangu, Neil Trushin, Ryan J. Elias, Jonathan Foulds, Joshua Muscat, John P. RichieThe addition of charcoal
in cigarette filters may be an effective
means of reducing many toxicants from tobacco smoke. Free radicals
are a highly reactive class of oxidants abundant in cigarette smoke,
and here we evaluated the effectiveness of charcoal to reduce free
radical delivery by comparing radical yields from commercially available
cigarettes with charcoal-infused filters to those without and by examining
the effects of incorporating charcoal into conventional cigarette
filters on radical production. Commercial cigarettes containing charcoal
filters produced 40% fewer gas-phase radicals than did regular cellulose
acetate filter cigarettes when smoked using the International Organization
of Standardization (ISO, p = 0.07) and Canadian Intense
(CI, p < 0.01) smoking protocols. While mean-particulate-phase
radicals were 25–27% lower in charcoal cigarettes, differences
from noncharcoal products were not significant (p = 0.06–0.22). When cellulose acetate cigarette filters were
modified to incorporate different types and amounts of activated charcoal,
reductions in gas-phase (>70%), but not particulate-phase, radicals
were observed. The reductions in gas-phase radicals were similar for
the three types of charcoal. Decreases in radical production were
dose-responsive with increasing amounts of charcoal (25–300
mg) with as little as 25 mg of activated charcoal reducing gas-phase
radicals by 41%. In all studies, charcoal had less of an effect on
nicotine delivery, which was decreased 33% at the maximal amount of
charcoal tested (300 mg). Overall, these results support the potential
consideration of charcoal in cigarette filters as a means to reduce
exposure to toxic free radicals from cigarettes and other combustible
tobacco products.