The use of charcoal in modified cigarette filters for mainstream smoke carbonyl reduction

Abstract

Carbonyls are harmful and potentially harmful constituents (HPHCs) in mainstream cigarette smoke (MSS). Carbonyls, including formaldehyde and acrolein, are carcinogenic or mutagenic in a dose-dependent manner. Past studies demonstrate significant reduction of HPHCs by charcoal filtration. However, limits of charcoal filtration and cigarette design have not yet been investigated in a systematic manner. Objective data is needed concerning the feasibility of HPHC reduction in combustible filtered cigarettes. This systematic study evaluates the effect of charcoal filtration on carbonyl reduction in MSS. We modified filters of ten popular cigarette products with predetermined quantities (100–400 mg) of charcoal in a plug-space-plug configuration. MSS carbonyls, as well as total particulate matter, tar, nicotine, carbon monoxide (TNCO), and draw resistance were quantified. Significant carbonyl reductions were observed across all cigarette products as charcoal loading increased. At the highest charcoal loadings, carbonyls were reduced by nearly 99%. Tar and nicotine decreased modestly (<20%) compared to reductions in carbonyls. Increased draw resistance was significant at only the highest charcoal loadings. This work addresses information gaps in the science base that can inform the evaluation of charcoal filtration as an available technological adaptation to cigarette design which reduces levels of carbonyls in MSS.

Effect of Charcoal in Cigarette Filters on Free Radicals in Mainstream Smoke

“…In a previous study, up to 200 mg of charcoal was incorporated into filters without affecting draw resistance. 17 In the current experiments, we did not measure draw resistance, but even with the highest levels of charcoal, no differences in the numbers of puffs taken per cigarette were observed, suggesting that any effects on draw were minimal. We also did not test free radical production at charcoal levels beyond 300 mg due to anticipated increases in draw resistance, greater nicotine reduction, and potential complications concerning the incorporation of such large amounts during cigarette manufacture.…”

“…While using high levels of charcoal in filters may have limited feasibility, CF cigarettes with 45−180 mg of charcoal are currently commercially available. 15,17 Others have shown that a cavity of only ∼3 mm in the filter is sufficient to accommodate up to 100 mg of charcoal, an amount which substantially reduces gas-phase radicals. 17 Our current experimental approach to the construction of a modified filter was to demonstrate proof of principle rather than provide information on potential design strategies.…”

“…In a recent study, incremental increases in charcoal loading led to increases in carbonyl filtration efficiency from cigarettes. 17 Charcoal-filtered (CF) cigarettes are commercially available and consist of two basic designs: one with charcoal dispersed throughout the cellulose acetate filter (carbon-on-tow/Dalmatian style) or another where the charcoal is localized in a cavity (plug style). Cigarettes containing charcoal filters are sold in many countries including South Korea, Venezuela, Hungary, and Russia and dominate the market in Japan.…”

“…It can also depend on the vapor pressure, molecular weight, and polarity of the compound, among other factors. In a recent study, incremental increases in charcoal loading led to increases in carbonyl filtration efficiency from cigarettes . Charcoal-filtered (CF) cigarettes are commercially available and consist of two basic designs: one with charcoal dispersed throughout the cellulose acetate filter (carbon-on-tow/Dalmatian style) or another where the charcoal is localized in a cavity (plug style).…”

Selected Constituent Yield Variation in the Smoke of Commercial Cigarette Brands on the Japanese Market

“…Many cigarette brands on the Japanese market use charcoal filters. The effect of charcoal filtration on carbonyl reduction in mainstream cigarette smoke was reported (15). The study used filters of commercial cigarette brands which were modified to contain three to four different levels of charcoal in filters.…”