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| Journal of the New Zealand Medical Association,
15-April-2005, Vol 118 No 1213
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Scope for regulation of cigarette smoke toxicity: the case
for including charcoal filters
Murray Laugesen, Jefferson Fowles
A committed but
concerned smoker might ask—‘Which cigarette brand has the least
toxic emissions in its smoke?’ If a certain brand had significantly lower
emissions, we reasoned that smokers should be informed of the fact. If there was
such a brand, no cigarette manufacturer was making any such claim. In 2003, the
Ministry of Health had tested only two brands for emission toxicity. By 2004,
the Ministry was reviewing the Smoke-free Environments regulations, including
the possibility of regulating toxicity.
We looked first
at Japan, where two-thirds of cigarettes sold in the preceding 20 years had
charcoal filter tips, thought to possibly explain the lower rate of lung cancer
in male smokers in Japan versus the United States.1
The most popular Japanese brand, Mild Seven, probably the world’s
most popular charcoal brand, was sold in small quantities in New Zealand. Data
from the Ministry of Health in Tokyo,2 however,
showed that the Mild Seven charcoal filter cigarette, and other regular
cigarettes with charcoal filters did not lower emissions below the Canadian
regular brands average as published by the Government of British
Columbia.3 As charcoal is widely used in gas
masks and in chemical laboratories to adsorb gases, the reason for these
findings was unclear.
MethodCigarette
manufacturers’ reports and charcoal filter
references—Document collections at www.tobaccodocuments.org (previously
secret internal industry documents accessed by legal discovery) and www.pubmed.org (US Institutes of Medicine) were
searched on acrolein, cyanide, and charcoal. In addition, Swedish Match supplied
a short summary of past experiments with charcoal filters. (Wahlberg I. personal
communication, 2004).
Smoke
tests—Emissions from two charcoal filter brands, Mild Seven
regular, labelled 13 mg tar, and Mild Seven Lights, labelled 8 mg tar, were
compared with Holiday Extra Mild (9 mg tar), an acetate filter brand. (The
labels for tar were based on the ISO method—puff volume 35 ml, puff
interval 60 seconds, puff duration 2 seconds, no holes covered).
The Mild Seven charcoal filter brands were purchased in
Newmarket, Auckland in 2004, and analysed by Labstat International Inc,
Kitchener, Ontario, Canada, using the Health Canada intensive machine smoking
method (55-ml puff volume, puff duration of 2 seconds, 30 seconds between puffs,
and all ventilation holes covered). For comparison, we used data from Holiday
Extra-mild cigarettes, purchased in Wellington in 2002, and also tested at that
time by Labstat by the same intensive machine smoking
method.4 For both studies, we tested a short
list of toxicants known from industry documents to be reduced by charcoal
filters. Brands were tested for tar and nicotine; for the respiratory toxicants
acrolein, acetaldehyde, formaldehyde; and for the cardiovascular toxicants
carbon monoxide and hydrogen cyanide.
Spreadsheet
scenarios—We created emissions spreadsheets containing the observed
emissions for each brand. Then we changed certain emissions to simulate the
effects of regulation for charcoal filters and/or switching to brands with lower
emission toxicity.5 We ran separate estimations
of each brand’s observed toxicity (with an acetate filter), then with a
combined acetate-charcoal filter, assuming the acetate functioned as before, and
the charcoal removed 75% of acetaldehyde, acrolein, benzene, hydrogen cyanide,
and formaldehyde, as found on emission testing of mainstream smoke from that
brand of (acetate filter) cigarette.
ResultsCigarette
company documents—In 1964-5, RJ Reynolds, and British American
Tobacco (BAT) scientists showed that charcoal filters lowered hydrogen cyanide
in smoke by 74% to 78%,6,7 and aldehydes by 75%
to 95%.7 In the 1990s, Swedish Tobacco, before
it sold its cigarette business and became Swedish Match, compared two 80%
ventilated cigarette brands, one with a charcoal filter, the other with a
cellulose acetate filter. Charcoal reduced the gas phase components by 80%
compared with the acetate filter cigarette. The greatest reductions were found
for aromatic hydrocarbons, nitriles, and ketones. (Wahlberg I. personal
communication, 2004).
Observed effects in smoke
test results—Labstat Inc reported that in both variants of Mild
Seven charcoal filter cigarettes, the charcoal granules were mixed and
inseparable from the cellulose acetate portion of the ‘dual filter’,
so that the charcoal could not be weighed. From our own visual examination, it
appeared that the charcoal was a very minor component of the filter.
Table 1 shows
that on testing by intensive machine smoking, emissions for tar, nicotine, and
carbon monoxide for all three brands were much higher than the levels given on
the packet label (which were based on the less intense ISO method).
Table 1. Per cigarette emissions in mainstream
smoke of three brands sold in New Zealand, with and without charcoal filters,
tested by intensive smoking machine method at Labstat Inc Canada
#Value
on packet label was determined by ISO method; na = not available; *p≤0.05
and, **p≤0.01, with respect to the value for Holiday Extra
Mild.
Compared with
Holiday Extra-Mild, the Mild Seven charcoal filter brands (both regular and
lights) gave significantly lower emissions for the respiratory toxicants
acrolein (p<0.01), and formaldehyde (p<0.01). For acetaldehyde, a
respiratory toxicant, and carcinogen, levels were not significantly different in
the charcoal brands. Emissions of hydrogen cyanide, a cardiovascular toxicant,
tended to be higher in the smoke of the Mild Seven brands, than for Holiday
Extra-Mild. On spreadsheet simulation, assuming untested analytes were the same
in all three brands, overall relative brand toxicity for Holiday Extra Mild was
intermediate between the two Mild Seven brand variants.
Estimated effects on
overall identifiable toxicity—Estimating from the emissions
spreadsheet, we scored the relative toxicity of the average of British Columbian
regular brands under intensive conditions as the standard, as 1.00. Adding a
charcoal filter reduced overall estimated identifiable toxicity by 43% to 0.57.
The estimated overall relative emission toxicity of Holiday Extra Mild under
intensive smoking conditions with an estimated score of 1.39, was higher than
for Canadian brands. Adding a charcoal filter similarly reduced HEM’s
overall identifiable toxicity by 44% to 0.78. The emission toxicity of
‘Export A full flavor’ was among the lowest of Canadian brands at
0.85: but was estimated to be lower still at 0.49 with an efficient charcoal
filter—a 42% reduction.
Non-cancer
risk—Substituting in the emissions spreadsheet, for Canadian
regular brands on average, a charcoal filter (see Method) reduced the estimated
cardiovascular and respiratory identifiable
toxicity by 72% and 74% respectively.
For Holiday Extra-mild, the reduction was 72% and 75% respectively. No method
was available for assessing what fraction of these reductions might be
applicable to total non-cancer smoking risk. Thus no non-cancer mortality
reduction estimate can be made.
Cancer
risk—The Canadian regular brands (overall total relative toxicity
score 1.00) provided the standard score for cancer toxicity of 0.39, based on an
estimated 39% of cigarette-attributed deaths in New Zealand in 2000 being
due to cancers.8 With a charcoal filter, cancer
toxicity reduced 13%, from 0.39 to 0.34, as we assumed no reduction of
1,3-butadiene, the main carcinogen. As identifiable cancer risk represented 35%
of total cancer risk,5 total cancer risk from
smoking reduced by (0.35*13) = 4.6%. This is a smaller but more firmly based
estimate than is available for cardiorespiratory risk, where the main benefits
of charcoal filters can be achieved.
If regulation utilised both brand and filter differences in
emission toxicity, (HEM without a charcoal filter, compared with ‘Export A
full flavor’ fitted with a charcoal filter), the difference was from 1.39
to 0.49, a 65% reduction in identifiable toxicity exposure overall, and a 47%
reduction in identifiable cancer toxicity exposure. These relative toxicities
are based on toxicant to nicotine ratios. If identifiable cancer risk reduced
47%, from 0.55 to 0.29, then total cancer risk from smoking can be lowered 47%*
0.35,5 that is, by 16.5% if charcoal filters
and other differences in brand toxicity are utilised. Were Holiday
Extra-mild’s emissions found to be typical of New Zealand cigarettes (it
is the only brand fully tested so far), then in 2000, cigarette cancer
deaths8 could have been 280 fewer.
Discussion
This study shows that:
Descriptors
on cigarette packets—In view of current interest in banning of
misleading descriptors as a possible outcome of the Ministry of Health’s
current review of packet labelling, we note that of the three brands studied,
whether considering the tar ratings on the side of the packet, the descriptors
‘light’, ‘extra-mild,’ or the filter description
‘charcoal filter’, none was matched by reduced toxicant emissions.
Our findings illustrate the need for Government to revise its regulations and
ban misleading labels on cigarette packets unless the claims can be
substantiated.
Limitations of the
study—Findings are limited to the brands we studied, and to the
time of purchase. Manufacturers may have since changed a brand’s design or
tobacco blend and consequent emissions, as most emissions are not monitored by
the Ministry of Health. In the current state of science we are unable to
quantitatively describe the relationship between non-cancer toxicants in smoke
and future disease risk.
Other smoke hazards including reactive oxygen species remain
unmeasured. Some toxicants are known to interact. Also smoking machines measure
the toxicant exposure of the machine, whereas smokers may inhale more
intensively, and also exhale some of the gases, thus retaining and absorbing
some gases more than others. Further, actual toxicant exposure implies
measurement of the inhaled smoke. Combining effects from charcoal filters and
other brand differences5 assumes independent
effects, which in practice may not be fully realisable, as some interaction may
be difficult to avoid.
The charcoal
filter—The light dusting of charcoal found in Mild Seven filters
may satisfy consumer taste and conform nominally to its label. It does not
exploit charcoal’s toxicant-reducing potential. Smokers may take time to
become accustomed to the taste of charcoal filter cigarettes, but if these
filters are mandated across all brands, smokers would buy and smoke them.
Besides Mild Seven, BAT’s Kent brand had a charcoal filter, but it also
appeared to contain little charcoal. Charcoal filter cigarettes need to contain
active charcoal (with greater surface areas and pores, up to 180 mg per
cigarette) if they are to maximally reduce toxicant gases. Regulations will need
to tilt manufacture towards maximally effective filters, against the
manufacturer’s wish not to upset the smoker.
This reports of cigarette chemists over the past 40 years
are in line with the large apparent reductions in emissions recently reported by
manufacturers; in 2004 for the Advance brand’s trionic (charcoal,
cellulose acetate, resin) filter9, and in 2005
for Philip Morris’ carbon filters technology.10
These charcoal filter cigarettes are currently being test-marketed in the
United States, but there is no sign of them being launched in New Zealand as
yet.
Regulation for effective filters should extend to filters
sold loose, as in New Zealand loose cigarette tobacco accounts for one-quarter
of all tobacco sold for smoking, and for over half of tobacco smoked by Maori.
As the excess cumulative premature death risk of continuing
to smoke is 50%, it is obvious that even if regulation reduces cigarette smoke
toxicity substantially, smoking will remain a highly dangerous activity.
Quitting is still the best advice.
The introduction of acetate filters in cigarettes in the
1960s led to soaring sales, encouraged by tobacco advertising. A new filter
could not easily repeat this now, in the face of advertising and smoking bans,
anti-smoking media campaigns, and tobacco taxation policies. As cigarette
toxicity is regulated, however, these support measures should be increased.
Author information:
Murray Laugesen Public Health Physician, Health New Zealand Ltd, Devonport,
Auckland; Jefferson Fowles, Senior Scientist, ESR (Institute of Environmental
Science and Research), Porirua
Acknowledgement
Heart Foundation of New Zealand funded this study.
Correspondence: Dr
Murray Laugesen, Health New Zealand Ltd, PO Box 32 099, Devonport, Auckland.
Email: laugesen@healthnz.co.nz
What
this paper adds
This is the first
published report comparing what charcoal filters can do in a cigarette company
laboratory with what they do in a commercial cigarette.
Over the last 40 years
cigarette company scientists have reported that charcoal can reduce aldehydes
and hydrogen cyanide emissions in cigarette smoke by 75%-80%. In two Mild Seven
charcoal filter brand variants sold in New Zealand containing minimal charcoal,
no such reduction in these emissions was seen.
Emission reductions seen
with the charcoal filters as reported 40 years ago, could today lower a
brand’s overall identifiable toxicity by over 40%, mainly by reducing
gases toxic to lungs, heart and blood vessels. Whether overall total brand
toxicity would be reduced by this much is uncertain, as currently unidentified
toxicants may not be susceptible to removal by charcoal filters. With more
certainty, effective filters could reduce total cigarette cancer risk by at
least 5%, or 80 deaths a year.
References
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