Cigarette filter-based assays as proxies for toxicant exposure and smoking behavior--a literature review

A Low-Cost, High-Throughput Digital Image Analysis of Stain Patterns on Smoked Cigarette Filter Butts to Estimate Mainstream Smoke Exposure

Standard machine smoking protocols provide useful information for examining the impact of design parameters, such as filter ventilation, on mainstream smoke delivery. Unfortunately, their results do not accurately reflect human smoke exposure. Clinical research and topography devices in human studies yield insights into how products are used, but a clinical setting or smoking a cigarette attached to such a device may alter smoking behavior. To better understand smokers' use of filtered cigarette products in a more natural environment, we developed a low-cost, high-throughput approach to estimate mainstream cigarette smoke exposure on a per-cigarette basis. This approach uses an inexpensive flatbed scanner to scan smoked cigarette filter butts and custom software to analyze tar-staining patterns. Total luminosity, or optical staining density, of the scanned images provides quantitative information proportional to mainstream smoke-constituent deliveries on a cigarette-by-cigarette basis. Duplicate sample analysis using this new approach and our laboratory's gold-standard liquid chromatography/tandem mass spectrometry (LC/MS/MS) solanesol method yielded comparable results (+7% bias) from the analysis of 20 commercial cigarettes brands (menthol and nonmentholated). The brands varied in design parameters such as length, filter ventilation, and diameter. Plots correlating the luminosity to mainstream smoked-nicotine deliveries on a per-cigarette basis for these cigarette brands were linear (average R2 > 0.91 for nicotine and R2 > 0.83 for the tobacco-specific nitrosamine NNK), on a per-brand basis, with linearity ranging from 0.15 to 3.00 mg nicotine/cigarette. Analysis of spent cigarette filters allows exposures to be characterized on a per-cigarette basis or a "daily dose" via summing across results from all filter butts collected over a 24 h period. This scanner method has a 100-fold lower initial capital cost for equipment than the LC/MS/MS solanesol method and provides high-throughput results (~200 samples per day). Thus, this new method is useful for characterizing exposure related to filtered tobacco-product use.

Cigarette smoke toxicity modes of action estimated by a bioluminescent bioreporter bacterial panel

Cigarette smoking is considered to be a risk factor for several chronic diseases and even premature death. However, despite the importance of this detrimental habit, little seems known in terms of the overall toxicity potential of its ingredients in humans. In this study, a panel of genetically modified bioluminescent bioreporter bacteria was used to evaluate its usefulness in estimating the cigarette smoke's complex molecular mixture on a bacterial toxicity-bioreporter panel, both filtered or unfiltered. This work enabled to confirm the usefulness of cigarette filters, with better protection found in higher priced brands despite both having genotoxic and cytotoxic attributes. Quorum sensing interference was also shown, which may explain why cigarette smokers are at greater risk for pulmonary infections. Moreover, the findings of this study support the fact that the filter is a dominating contributor to reducing the harm caused by cigarette smoke. Increased efforts should be conducted to reduce the harmful effects of cigarette smoke, via increasingly effective filters. To conclude, the panel of bioreporter bacteria was found to be useful in the evaluation of the general effect of the toxic mixture found in cigarette smoke and therefore has the potential to be used in cigarette research, helping researchers pinpoint the reduction of toxicity when working with filter improvement.

Impact of Filter on the Estimation of Quantitative Mixture Risk Caused by Some Chemical Constituents Generated from Popular Cigarette Brands in Iran

Background

This study was conducted to evaluate the impact of filter on the eventual carcinogenic and non-carcinogenic risks caused by the main toxic constituents of popular cigarette brands in Iran.

Methods

At this laboratory study, the concentration of benzene, formaldehyde, arsenic, and cadmium in the mainstream smoke of 11 popular cigarette brands in Iran, on the without and with-filter modes was determined based on an established method. The hazard quotient (HQ), incremental lifetime cancer risk (ILCR), and mixture quantitative risk assessments (QRAs) were performed based on the QRA method recommended by United States Environmental Protection Agency (USEPA).

Findings

The mean of HQ due to benzene, formaldehyde, arsenic, and cadmium in without-filter cigarette smoke was from 3.96 to 3505. The findings indicated that the HQs related to benzene, formaldehyde, arsenic, and cadmium in cigarette smoke were decreased with filter by 48.3%, 25.3%, 37.6%, and 49.1%, respectively. The filter of cigarette decreased ILCR of benzene, formaldehyde, arsenic, and cadmium in cigarette smoke by 53.02%, 25.31%, 37.70%, and 61.01%, respectively. The mixture of non-carcinogenic and carcinogenic estimated risks due to inhalation of studied cigarettes smoke was very high and unacceptable.

Conclusion

The cigarette filter plays an essential role in reducing inhalation exposure to hazardous compounds in mainstream cigarette smoke; nevertheless, the average of overall mixture HQs and ILCRs estimated caused by studied compounds was higher than the acceptable value. It is recommended that future empirical studies investigate the impact of the type of fiber used in cigarette filter on reducing carcinogenic and non-carcinogenic risks caused by cigarette smoke.

A cross-category puffing topography, mouth level exposure and consumption study among Italian users of tobacco and nicotine products

Actual use studies play a key part in evaluating the reduced risk potential of tobacco and nicotine products. This study was undertaken to determine the puffing topography, mouth level exposure (MLE) and average daily consumption (ADC) relating to two commercially available tobacco heating products (THPs) and a prototype electronic cigarette (or e-cigarette) among Italian non-mentholated 7 mg ISO tar cigarette smokers. The study was conducted in Milan, Italy, with three groups of approximately 50 participants. Groups 1 and 3 included adult smokers of 7 mg ISO tar tobacco cigarettes, and Group 2 consisted of both solus vapers and dual users of vapour and tobacco products. Amongst smokers, e-cigarette mean puff volumes (41.6 mL vs 41.3 mL) and mean puff durations (1.4 s vs 1.5 s) were similar to that of the cigarette, although the average usage session was significantly longer (1064.8 s vs 289.5 s) with a higher total number of puffs (58.6 vs 17.3), however this may be attributable to differences in product operation. There were no significant differences across puffing topography measurements observed between smokers (Group 1) and regular vapers/dual users (Group 2) when using the e-cigarette. As consistent with previous research, users took, on average, larger mean puff volumes when using a THP compared to the reference cigarette (C651), although puff numbers and puff durations remained similar. The average interval between puffs was considerably shorter for THP1.0(T) compared to THS2.4(T) (11.0 s vs 17.1 s). MLE to nicotine-free dry particulate matter and nicotine was significantly reduced for THP1.0(T) and THS2.4(T) compared to the tobacco cigarette (C651). MLE to nicotine was also significantly reduced for the e-cigarette (IS1.0(T)) compared to C651. The average daily consumption (ADC) of cigarettes by groups 1 and 3 were higher than the respective ADCs of both THP consumables. There were no significant differences in ADC when comparing the same product between different groups. Differences seen between sensory scores for each of the product categories may be attributed to fundamental differences in design and mode of operation resulting in very different characteristics of the aerosol generated.

PhenX: Agent measures for tobacco regulatory research

The current paper describes the PhenX (Phenotypes and eXposures) Toolkit Tobacco Regulatory Research Agent specialty area and the Agent Working Group's (WG's) 6-month consensus process to identify high-priority, scientifically supported measures for cross-study comparison and analysis. Eleven measures were selected for inclusion in the Toolkit. Eight of these are interviewer-administered or self-administered protocols: history of switching to lower tar and nicotine cigarettes, passive exposures to tobacco products, tobacco brand and variety (covering cigars, cigarettes and smokeless tobacco separately), tobacco product adulteration (vent-blocking or filter-blocking) and tobacco warning label exposure and recall. The remaining three protocols are either laboratory-based or visual inspection-based: measurement of nicotine content in smoked or smokeless tobacco products and the physical properties of these two classes of products. Supplemental protocols include a biomarker of exposure and smoking topography. The WG identified the lack of standard measurement protocols to assess subjective ratings of tobacco product flavours and their appeal to consumers as a major gap. As the characteristics of tobacco products that influence perception and use are tobacco regulatory research priorities, the reliable assessment of flavours remains an area requiring further development.

Assessment of tobacco heating product THP1.0. Part 8: Study to determine puffing topography, mouth level exposure and consumption among Japanese users

A four-arm study was undertaken in Japan to determine the puffing topography, mouth level exposure and average daily consumption by consumers of the tobacco heating products (THPs): the non-mentholated THP1.0(T), the mentholated THP1.0(M) and a tobacco heating system (THS). The extent of lip blocking of air inlet holes while using THP1.0(T) was also assessed. Groups 1, 2, and 4 included smokers, and group 3 included regular THP users. Smokers of 7-8 mg ISO nicotine free dry particulate matter (NFDPM) non-mentholated cigarettes took on average larger mean puff volumes from THPs than from conventional cigarettes, but puff numbers and durations were similar. Mouth level exposure to NFDPM and nicotine levels were significantly lower when using THPs than conventional cigarettes. Similar trends were observed among smokers of 7-8 mg ISO NFDPM mentholated cigarettes who used mentholated cigarettes and THP1.0(M). Regular users of commercial THS had similar puffing behaviours irrespective of whether they were using THS or THP1.0(T), except for mean puff volume which was lower with THP1.0(T). No smokers blocked the air inlet holes when using THP1.0(T). The puffing topography results support the machine puffing regime used to generate toxicant emissions data and in vitro toxicology testing.

Reference change values in concentrations of urinary and salivary biomarkers of exposure and mouth level exposure in individuals participating in an ambulatory smoking study

Background

Modified-risk tobacco products (MRTPs) are being developed that may contribute to tobacco harm reduction. To support reduced exposure or risk claims, a scientific framework needs to be developed to assess the validity of claims and monitor consumers after product launch. We calculated reference change values (RCVs) for biomarker of exposure (BoE): salivary cotinine and hydroxycotinine; and urinary total nicotine equivalents, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and creatinine. Mouth-level exposure (MLE) to nicotine and tar were also recorded in an ambulatory setting to characterise variation among smokers in their everyday environment.

Methods

This non-residential, observational study was conducted over 3.5 years across 10 sites in Germany. Smokers of the same commercial 10 mg ISO tar product were included in the study (N=1011). Urine samples, questionnaires and cigarette filters were collected every 6 months for a total of seven timepoints.

Results

Greater variability in BoEs was observed compared with confined clinical studies. Gaussian distributed data showed 2-sided values over 100%, which are uninformative for decreases. The proportion of significant changes increased slightly among switchers, probably as a result of additional variability due to the range of products used post-switching. Overall proportions of changes remained small, consistent with literature reporting that when switching to a different tar yield cigarette, smokers partially compensate by changing their smoking behaviour.

Conclusion

Variability estimates and RCVs can be useful for monitoring subjects' BoE and MLE endpoints in longitudinal smoking studies where subjects are followed in their own environment and to aid sample size calculation of studies involving these endpoints.

A longitudinal study of smokers' exposure to cigarette smoke and the effects of spontaneous product switching

A challenge in investigating the effect of public health policies on cigarette consumption and exposure arises from variation in a smoker's exposure from cigarette to cigarette and the considerable differences between smokers. In addition, limited data are available on the effects of spontaneous product switching on a smoker's cigarette consumption and exposure to smoke constituents. Over 1000 adult smokers of the same commercial 10mg International Organization for Standardization (ISO) tar yield cigarette were recruited into the non-residential, longitudinal study across 10 cities in Germany. Cigarette consumption, mouth level exposure to tar and nicotine and biomarkers of exposure to nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone were measured every 6months over a 3 and a half year period. Cigarette consumption remained stable through the study period and did not vary significantly when smokers spontaneously switched products. Mouth level exposure decreased for smokers (n=111) who switched to cigarettes of 7mg ISO tar yield or lower. In addition, downward trends in mouth level exposure estimates were observed for smokers who did not switch cigarettes. Data from this study illustrate some of the challenges in measuring smokers' long-term exposure to smoke constituents in their everyday environment.

Providing a Science Base for the Evaluation of Tobacco Products

OBJECTIVE

Evidence-based tobacco regulation requires a comprehensive scientific framework to guide the evaluation of new tobacco products and health-related claims made by product manufacturers.

METHODS

The Tobacco Product Assessment Consortium (TobPRAC) employed an iterative process involving consortia investigators, consultants, a workshop of independent scientists and public health experts, and written reviews in order to develop a conceptual framework for evaluating tobacco products.

RESULTS

The consortium developed a four-phased framework for the scientific evaluation of tobacco products. The four phases addressed by the framework are: (1) pre-market evaluation, (2) pre-claims evaluation, (3) post-market activities, and (4) monitoring and re-evaluation. For each phase, the framework proposes the use of validated testing procedures that will evaluate potential harms at both the individual and population level.

CONCLUSIONS

While the validation of methods for evaluating tobacco products is an ongoing and necessary process, the proposed framework need not wait for fully validated methods to be used in guiding tobacco product regulation today.

A Real-Time Fast-Flow Tube Study of VOC and Particulate Emissions from Electronic, Potentially Reduced-Harm, Conventional, and Reference Cigarettes

Tobacco-free electronic cigarettes (e-cigarettes), which are currently not regulated by the FDA, have become widespread as a "safe" form of smoking. One approach to evaluate the potential toxicity of e-cigarettes and other types of potentially "reduced-harm" cigarettes is to compare their emissions of volatile organic compounds (VOCs), including reactive organic electrophillic compounds such as acrolein, and particulate matter to those of conventional and reference cigarettes. Our newly designed fast-flow tube system enabled us to analyze VOC composition and particle number concentration in real-time by promptly diluting puffs of mainstream smoke obtained from different brands of combustion cigarettes and e-cigarettes. A proton transfer reaction time-of-flight mass spectrometer (PTRMS) was used to analyze real-time cigarette VOC emissions with a 1 s time resolution. Particles were detected with a condensation particle counter (CPC). This technique offers real-time analysis of VOCs and particles in each puff without sample aging and does not require any sample pretreatment or extra handling. Several important determining factors in VOC and particle concentration were investigated: (1) puff frequency; (2) puff number; (3) tar content; (4) filter type. Results indicate that electronic cigarettes are not free from acrolein and acetaldehyde emissions and produce comparable particle number concentrations to those of combustion cigarettes, more specifically to the 1R5F reference cigarette. Unlike conventional cigarettes, which emit different amounts of particles and VOCs each puff, there was no significant puff dependence in the e-cigarette emissions. Charcoal filter cigarettes did not fully prevent the emission of acrolein and other VOCs.

Mouth-level intake of benzo[a]pyrene from reduced nicotine cigarettes

Cigarette smoke is a known source of exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs), especially benzo[a]pyrene (BaP). Exposure to BaP in cigarette smoke is influenced by how a person smokes and factors, such as tobacco blend. To determine whether sustained use of reduced-nicotine cigarettes is associated with changes in exposure to nicotine and BaP, levels of BaP in spent cigarette filter butts were correlated with levels of BaP in cigarette smoke to estimate mouth-level intake (MLI) of BaP for 72 daily smokers given three progressively reduced nicotine content cigarettes. Urinary cotinine, a marker of nicotine exposure, and urinary 1-hydroxypyrene (1-HOP), a marker of PAH exposure, were measured throughout the study. Median daily BaP MLI and urine cotinine decreased in a similar manner as smokers switched to progressively lower nicotine cigarettes, despite relatively constant daily cigarette consumption. 1-HOP levels were less responsive to the use of reduced nicotine content cigarettes. We demonstrate that spent cigarette filter butt analysis is a promising tool to estimate MLI of harmful chemicals on a per cigarette or per-day basis, which partially addresses the concerns of the temporal influence of smoking behavior or differences in cigarette design on exposure.

Cigarette smoking topography among alternative school youth: why African American youth smoke less but are at higher long-term risk

A paradox exists in health disparities research where African-American cigarette smokers consume fewer cigarettes per day, yet experience higher rates of tobacco-related disease compared to White American smokers. In this study we conducted focus group interviews among alternative high school youth (N = 78; age 18-19 years old) in an urban area in Southwest Texas to investigate if African-American youth smoke cigarettes differently than their White-American and Hispanic-American counterparts. The majority of African-American participants reported inhaling deeper and smoking their cigarettes "to the filter" because of their concern over wasting any part of an expensive cigarette. White and Hispanic respondents most often put out their cigarettes closer to the middle, and did not express concern about wasting cigarettes. The implication from this qualitative study is that because African Americans smoke differently they are exposed to a higher level of harmful particulate per cigarette. Further research on smoking topography is warranted.

Development of a method to estimate mouth-level benzo[a]pyrene intake by filter analysis

BACKGROUND

Benzo[a]pyrene (BaP) is one of the most potent carcinogens generated in cigarette smoke. During smoking, cigarette filters trap a significant portion of mainstream smoke benzo[a]pyrene. This trapped portion is proportional to what exits the end of the filter and is drawn into the mouth of smokers.

METHODS

We developed a new method to estimate mouth-level BaP intake using filter analysis. In this analysis, cigarettes are smoked by a smoking machine using a variety of conditions to yield a range of mainstream smoke deliveries, which approximate a range of human puffing characteristics. Mainstream smoke BaP collected on Cambridge filter pads and the corresponding 1-cm mouth-end cigarette filter butts is extracted, purified by solid-phase extraction, and quantified by high-performance liquid chromatography coupled with a fluorescence detector. On the basis of the amount of BaP retained in cigarette butts and the amount collected on pads, we can relate them using a linear regression model.

RESULTS

Using this model and subsequently analyzing cigarette filters collected from smokers, we are able to estimate their mouth-level intakes, which smokers received when they consumed cigarettes. We made a series of measurements using research cigarettes and select commercial cigarettes having a wide range of machine smoke "tar" and nicotine deliveries.

CONCLUSIONS

In all cases, results indicate a linear relation of BaP between cigarette filter butts and Cambridge filter pads, with R(2) ranging from 0.93 to 0.98.

IMPACT

This technique provides a noninvasive means to examine intake on a per cigarette basis to examine both exposure and behavioral aspects of smoking.

Mouth level smoke exposure using analysis of filters from smoked cigarettes: a study of eight countries

The analysis of spent cigarette filters enables the estimation of the nicotine and tar (nicotine-free dry particulate matter) yields obtained by smokers in their everyday environment and has been shown to correlate well with biomarkers of exposure. Leading products across the range of ISO tar yields were selected from Australia, Brazil, Canada, Germany, Japan, New Zealand, South Africa and Switzerland. At least fifty demographically representative smokers were recruited per product. Subjects, ≥ 21 years of age and smoking ≥ 5 cigarettes per day, were asked to collect ≥ 15 filters from cigarettes they had smoked. The collected filters were analysed for nicotine and UV absorbance to enable the smokers' mouth level exposure to nicotine and tar to be estimated and a comparison of countries and tobacco blend styles to be made. Smoking history data were also collected. More than 80,000 filters were collected from 5703 smokers of 106 products from eight countries. Mean ± SD estimated nicotine exposures per cigarette and per day ranged from 0.93 ± 0.34 mg/cigarette (Brazil) to 1.77 ± 0.69 mg/cigarette (South Africa) and from 16.4 ± 11.1mg/day (Germany) to 31.5 ± 14.8 mg/day (South Africa), respectively. Male smokers obtained higher mean estimated tar and nicotine exposures than female smokers. These gender differences were statistically significant for six countries. Significant correlations were found between estimated nicotine exposure and ISO nicotine yield, and between estimated tar exposure and ISO tar yield (p<0.001).

A study to evaluate the effect on Mouth Level Exposure and biomarkers of exposure estimates of cigarette smoke exposure following a forced switch to a lower ISO tar yield cigarette

A forced switch to a lower ISO tar yield cigarette was used in a clinical study, conducted in Germany, that compared two methods of estimating exposure to cigarette smoke. Pre- and post-switch estimates of Mouth Level Exposure (MLE) to nicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), pyrene and acrolein were obtained by chemical analysis of spent cigarette filters for nicotine content. Similarly, pre- and post-switch estimates of uptake of these smoke constituents were achieved by analysis of corresponding urinary biomarkers of exposure (BoE): total nicotine equivalents; total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL); total 1-hydroxypyrene (1-OHP), and 3-hydroxypropyl-mercapturic acid (3-HPMA), plus the nicotine metabolite cotinine, in plasma and saliva. Three hundred healthy volunteers were recruited comprising 100 smokers of each of 9-10 and 4-6 mg ISO tar yield cigarettes and 50 smokers of 1-2mg ISO tar yield cigarettes and 50 non-smokers. Fifty smokers of each of the 9-10 and 4-6 mg ISO tar yield cigarettes took part in the switching aspects of this study whilst the remaining smokers formed non-switching control groups who smoked their usual ISO tar yield cigarette throughout the study. After 5 days, all subjects were admitted into a clinic where baseline measures of MLE and BoE were obtained. The 10mg switching group was then switched to the 4 mg ISO tar yield cigarette and the 4 mg ISO tar yield switching group switched to the 1mg cigarette. Subjects returned home for 12 days, continuing to smoke the supplied cigarettes before being readmitted into the clinic where samples were collected for MLE and BoE analysis. Changes in daily exposure estimates were determined on a group and individual basis for both methods. The pre- to post-switch directional changes in MLEs and their corresponding BoEs were generally consistent and the MLE/BoE relationship maintained. Switching to a lower yield cigarette generally resulted in reductions in exposure with the resultant exposure level being similar to that seen in regular smokers of the lower yield cigarette.

Estimation of nicotine and tar yields from human-smoked cigarettes before and after the implementation of the cigarette ignition propensity regulations in Canada

In 2005, Human-Smoked (HS) tar and nicotine yields from commercial Canadian cigarettes were determined using a part filter analysis method to obtain estimates representative of human smoking behavior. In 2006, new cigarette designs were introduced to ensure compliance with the Canadian Low Ignition Propensity (LIP) regulations. It was not known how the changes in product design would affect HS yields. To assess the impact of the cigarette design modifications on HS yields, a further group of Canadian smokers was recruited for smoking the modified version of 10 products previously assessed. No differences in estimated HS tar yields were found between products following product modification. The HS nicotine yield was different for one product. In general, HS yields were higher than ISO machine yields while Canadian intense machine yields were more representative of the maximum HS yields. The same product ranking order was obtained for HS yields and the two machine yields but differences between the mean HS yields and ISO yields were smaller as the product ISO yields increased. Higher HS yields were measured when products were smoked by male smokers. The methodology used in this study showed the wide range of HS yields obtained by smokers as well as a good degree of stability in average HS yields just before and after the introduction of LIP regulations.

Estimation and correlation of cigarette smoke exposure in Canadian smokers as determined by filter analysis and biomarkers of exposure

A clinical study conducted in Canada compared two methods of estimating exposure to cigarette smoke in 192 volunteer subjects: 43 smokers of 4-6 mg, 49 of 8-12 mg and 50 of 14-15 mg ISO tar yield cigarettes and 50 non-smokers. Estimates of mouth level exposure (MLE) to nicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), pyrene and acrolein were obtained by chemical analysis of spent cigarette filters. Estimates of smoke constituent uptake were achieved by analysis of urinary biomarkers for total nicotine equivalents (nicotine, cotinine, trans-3'-hydroxycotinine plus their glucuronide conjugates), NNK (total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) plus glucuronide), pyrene (1-hydroxy pyrene plus glucuronide) and acrolein (3-hydroxylpropyl-mercapturic acid) plus the nicotine metabolite cotinine in plasma and saliva. The objective of our study was to confirm the correlations between measures of human exposure obtained by filter analysis and biomarkers. Significant correlations (p<0.001) were found between MLE and the relevant biomarker for each smoke constituent. The adjusted values of the Pearson correlation coefficients (r) were 0.80 (nicotine), 0.77 (acrolein) and 0.44 (pyrene). NNK correlations could not be obtained because of the low NNK yield of Canadian cigarettes. Unexpectedly high levels of acrolein biomarker found in non-smokers urine on one of the two days sampled emphasised the need for more than one sampling occasion per period and an awareness of non-tobacco sources of smoke constituents under investigation. No consistent dose response, in line with ISO tar yield smoked, of MLE estimates was found for nicotine, pyrene and acrolein and respective biomarkers. The influence of demographics on our results has also been examined.

A survey of mouth level exposure to cigarette smoke in the United States

Smoke yields determined by a machine-based smoking method cannot adequately predict exposures experienced by human smokers. In this work, a filter analysis technique which addresses this fundamental limitation was used to measure mouth level exposures (MLE) to tar and nicotine in 1330 smokers of 26 brand-styles of US cigarettes covering a wide range of machine-generated yields. Despite the high degree of variability observed among individual smokers, MLEs were significantly correlated with machine-derived tar and nicotine yields (r=0.423 for nicotine MLE/cigarette; r=0.493 for tar MLE/cigarette; p<0.001 for both). Mean tar and nicotine MLE was higher for males than for females. Mean MLE across races was generally similar. Menthol cigarettes tended toward lower MLE than non-menthol cigarettes and King-Size cigarettes (≈ 83 mm) tended toward lower MLE than 100's cigarettes (≈ 100 mm), though those trends were not statistically significant. There were good agreements between MLEs measured in a group of 159 subjects smoking their usual cigarette brand-style on two separate occasions and between two independent groups of subjects smoking the same brand-styles. The results indicated that the filter analysis method used had sufficient precision to show similarity among groups.

Direct measurement of toxicants inhaled by water pipe users in the natural environment using a real-time in situ sampling technique

While narghile water pipe smoking has become a global phenomenon, knowledge regarding its toxicant content and delivery, addictive properties, and health consequences is sorely lagging. One challenge in measuring toxicant content of the smoke in the laboratory is the large number of simplifying assumptions that must be made to model a "typical" smoking session using a smoking machine, resulting in uncertainty over the obtained toxicant yields. In this study, we develop an alternative approach in which smoke generated by a human water pipe user is sampled directly during the smoking session. The method, dubbed real-time in situ sampling (RINS), required developing a self-powered portable instrument capable of automatically sampling a fixed fraction of the smoke generated by the user. Instrument performance was validated in the laboratory, and the instrument was deployed in a field study involving 43 ad libitum water pipe use sessions in Beirut area cafés in which we measured inhaled nicotine, carbon monoxide (CO), and water pipe ma'ssel-derived "tar." We found that users drew a mean of 119 L of smoke containing 150 mg of CO, 4 mg of nicotine, and 602 mg of ma'ssel-derived "tar" during a single use session (mean duration = 61 min). These first direct measurements of toxicant delivery demonstrate that ordinary water pipe use involves inhaling large quantities of CO, nicotine, and dry particulate matter. Results are compared with those obtained using the Beirut method smoking machine protocol.

Smoking intensity before and after introduction of the public place smoking ban in Scotland

A study was performed to determine whether cigarettes were smoked more intensely outside of public venues in Scotland, compared to indoors, after introduction of the public place smoking (PPS) ban. It was conducted in three waves: before the ban, immediately after and 6 months after introduction. The study included 322 regular smokers of four cigarette brand variants. Filter analysis measurements were used to estimate the human-smoked yields of tar and nicotine from cigarettes smoked predominantly inside (before the ban) or outside (after the ban) public venues. Self-reported cigarette consumption data were also collected. Numbers of cigarettes smoked indoors in public places fell dramatically after the ban. There was a corresponding rise in smoking incidence in outdoor public locations. The ban did not significantly affect the total number of cigarettes smoked by the subjects over the weekends investigated. Human-smoked yields of tar and nicotine decreased slightly after the introduction of the ban and some reductions were significant. Therefore, smoking outdoors at public venues, following the PPS ban, did not increase smoking intensity. Any changes in smoking behaviour that may have occurred had little effect on mainstream smoke exposure or cigarette consumption for those that continued to smoke.