Determination of tar, nicotine, and carbon monoxide yields in the mainstream smoke of selected international cigarettes

Objective: Survey of nicotine, tar, and carbon monoxide (CO) smoke deliveries from 77 cigarette brands purchased in 35 countries was conducted using a standardised machine smoking method. The goal of this study was to determine regional variations and differences in the tar, nicotine, and CO smoke yields of a cigarette brand manufactured by a leading transnational corporation and of non-US locally popular cigarette brands.

Design: The majority of the cigarettes were purchased in each of the participating countries by delegate members of the World Health Organization and forwarded to the Centers for Disease Control and Prevention for analysis. Smoke deliveries were determined using a standardised smoking machine method and subsequent gravimetric and gas chromatography analysis.

Results: The smoke deliveries varied widely. Mainstream smoke deliveries varied from 6.8 to 21.6 mg tar/cigarette, 0.5 to 1.6 mg nicotine/cigarette, and 5.9 to 17.4 mg CO/cigarette. In addition to the smoke deliveries, the cigarettes were examined to determine physical parameters such as filter composition, length, and ventilation levels.

Conclusion: Analysis of the smoke deliveries suggested that cigarettes from the Eastern Mediterranean, Southeast Asia, and Western Pacific WHO regions tended to have higher tar, nicotine, and CO smoke deliveries than did brands from the European, American, or African WHO regions surveyed.

     

Predictors of the development of elementary-school children's intentions to smoke cigarettes: hostility, prototypes, and subjective norms.

Children's intentions to smoke are reliable predictors of subsequent smoking and precede smoking initiation; thus identifying predictors of intentions is important for preventing or delaying smoking initiation. Children's hostility and sociability, mediated by the development of prototypes (i.e., social images of children who smoke cigarettes) and subjective norms regarding smoking among peers, were expected to predict the development of their intentions to smoke cigarettes in the future. Children in 2nd through 5th grades (N = 809) from a western Oregon community participated in a longitudinal study. Hostility and sociability were assessed by teachers' ratings, and prototypes, subjective norms, and intentions were assessed by self-report at each of the first four annual assessments. Children's intentions to smoke predicted whether they had tried cigarettes by the fifth assessment. For both genders, latent growth modeling demonstrated that hostility, but not sociability, predicted the development of smoking intentions. Children who were more hostile were more likely to have higher initial levels of intentions to smoke, and for boys this effect was mediated by their higher initial levels of subjective norms about smoking. Sociability was not related to the development of smoking cognitions for boys or girls. These results are discussed in terms of opportunities to intervene in early influences on smoking intentions.     

Incomplete compensation does not imply reduced harm: yields of 40 smoke toxicants per milligram nicotine in regular filter versus low-tar cigarettes in the 1999 Massachusetts Benchmark Study.

The yields of 40 toxic smoke constituents per mg nicotine were computed in three matched pairs of higher- and lower-tar cigarettes tested in the 1999 Massachusetts Benchmark Study. In the three pairs, 19, 20 and 17 compounds, respectively, exhibited significantly greater yields per mg nicotine in the lower-tar than the corresponding higher-tar brand. Based on the assumption that toxicant yields per mg nicotine were independent of smoking intensity, the minimum degree of nicotine compensation necessary to obtain equal or greater dosages of these toxic compounds from the lower-tar cigarette ranged from 0% to 73%. A smoker who compensates only incompletely for nicotine may thus obtain a higher dosage of a specific smoke toxicant from a lower-tar cigarette than from a higher-tar cigarette. From the toxicological standpoint, incomplete compensation for nicotine does not necessarily translate into harm reduction.     

Comparison of the nicotine content of tobacco used in bidis and conventional cigarettes

OBJECTIVE: To compare the nicotine content of 12 unfiltered brands of bidi cigarettes (hand rolled cigarettes imported from India) with 8 popular brands of filtered and unfiltered US and conventional cigarettes from India. MAIN OUTCOME MEASURES: Identical laboratory procedures were used to determine nicotine content (in duplicate) and physical characteristics. RESULTS: The nicotine concentration in the tobacco of bidi cigarettes (21.2 mg/g) was significantly greater than the tobacco from the commercial filtered (16.3 mg/g) and unfiltered cigarettes (13.5 mg/g). CONCLUSIONS: Bidi cigarettes contain higher concentrations of nicotine than conventional cigarettes. Therefore, it is logical to presume that bidi smokers are at risk of becoming nicotine dependent. These findings belief a popular belief among US teens that bidis are a safe alternative to commercial cigarettes.     

全缘马尾藻提取物对酵母膏诱导小鼠高尿酸血症的拮抗效应

本文主要研究全缘马尾藻在不同乙醇浓度(0%、25%、50%、75%)提取物对模型小鼠高尿酸血症的拮抗作用。利用酵母膏灌胃法建立小鼠高尿酸血症模型,测定小鼠血清尿酸(UA)水平,以及肝脏中黄嘌呤氧化酶(XOD)和腺苷脱氨酶(ADA)活性,并计算小鼠肝脏、肾脏器官指数,HE染色观察其肾脏组织病理学变化。结果表明,与空白组相比,酵母膏能极显著升高小鼠血清尿酸水平(p<0.01)、肝脏XOD及ADA活性(p<0.01)。与模型组相比,全缘马尾藻各醇浓度提取物均能降低血清UA水平、肝脏XOD及ADA活性,其中50%醇提取物组对降低血清UA水平具有极显著性意义(p<0.01),光镜下可见,治疗组多数小鼠肾小球、肾小管结构恢复正常。总体而言,全缘马尾藻提取物对酵母膏致小鼠高尿酸血症具有一定程度的缓解作用,其机制与尿酸代谢有关。      

Thirdhand smoke: heterogeneous oxidation of nicotine and secondary aerosol formation in the indoor environment

Tobacco smoking is well-known as a significant source of primary indoor air pollutants. However, only recently has thirdhand smoke (THS) been recognized as a contributor to indoor pollution due to the role of indoor surfaces. Here, the effects of relative humidity (<10% RH and ～ 45% RH) and substrate (cellulose, cotton, and paper) on secondary organic aerosol (SOA) formation from nicotine-ozone-NO(x) reactions are discussed. SOA formation from the sorbed nicotine-ozone reaction ([O(3)] = 55 ppb) varied in size distribution and number, depending on RH and substrate type, indicating the role of substrate and water interactions in SOA formation. This led to SOA yields from cellulose sorbed nicotine-ozone reaction of ～ 1 and 2% for wet and dry conditions, respectively. SOA formation from nicotine-NO(x) reactions was not distinguishable from background levels. Simultaneously, cellulose sorbed nicotine-ozone reaction kinetics ([O(3)] = 55 ppb) were obtained and revealed pseudofirst-order surface rate constants of k(1) = (1 ± 0. 5) × 10(-3) and k(1) < 10(-4) min(-1) under <10% and ～ 45% RH, respectively. Given the toxicity of some of the identified products and that small particles may contribute to adverse health effects, the present study indicates that exposure to THS ozonation products may pose additional health risks.     

Silphium L. extracts – composition and protective effect on fatty acids content in sunflower oil subjected to heating and storage

The influence of ethanol and hexane extracts from leaves, inflorescences, and rhizomes of Silphium perfoliatum, Silphium trifoliatum, Silphium integrifolium on fatty acid content changes in sunflower oil subjected to heating and storage was studied in comparison to the synthetic antioxidant – butylated hydroxyanisole (BHA). A positive effect of extracts made of above-ground and underground organs of Silphium on the durable quantitative composition of fatty acids was proven. Tested extracts elevated the value of change inhibition with reference to linoleic acid to a level comparable with BHA, and sometimes, in appropriate systems, they were characterized by better values (for oil stored for 180 days at room temperature, the inhibition coefficient for linoleic acid changes reached 4.6% for 0.04% BHA, and 7.09% for hexane extract made of S. trifoliatum inflorescences, 400 μl/2 g; for oil heated for 120 h, the inhibition coefficient of linoleic acid changes amounted to 11.32% for 0.06% BHA, and 15.69% for hexane extract made of S. perfoliatum rhizomes, 600 μl/2 g). It was found that active substances groups such as phenolic acids, flavonoids and terpenes were present in tested extracts.     

Do increases in cigarette prices lead to increases in sales of cigarettes with high tar and nicotine yields?

We used scanner data on cigarette prices and sales collected from supermarkets across the United States from 1994 to 2004 to test the hypothesis that cigarette prices are positively correlated with sales of cigarettes with higher tar and nicotine content. During this period the average inflation-adjusted price for menthol cigarettes increased 55.8%. Price elasticities from multivariate regression models suggest that this price increase led to an increase of 1.73% in sales-weighted average tar yields and a 1.28% increase in sales-weighted average nicotine yields for menthol cigarettes. The 50.5% price increase of nonmenthol varieties over the same period yielded an estimated increase of 1% in tar per cigarette but no statistically significant increase in nicotine yields. An ordered probit model of the impact of cigarette prices on cigarette strength (ultra-light, light, full flavor, unfiltered) offers an explanation: As cigarette prices increase, the probability that stronger cigarette types will be sold increases. This effect is larger for menthol than for nonmenthol cigarettes. Our results are consistent with earlier population-based cross-sectional and longitudinal studies showing that higher cigarette prices and taxes are associated with increasing consumption of higher-yield cigarettes by smokers.     

The nicotine market: an attempt to estimate the nicotine intake from various sources and the total nicotine consumption in some countries.

Tobacco--particularly smoked products--has been associated with great harm and growing public disapproval and can be expected to suffer in the marketplace. This situation has created opportunities for other less harmful nicotine-containing products such as smokeless tobacco and nicotine replacement products, which are gaining public support. Little is known about the level of nicotine intake in our society. Tobacco sales are known, but how much nicotine is extracted and actually absorbed by users is largely unknown. The present study is a first attempt to estimate uptake of nicotine from tobacco and nicotine replacement products and to map nicotine consumption in a few countries, with special emphasis on Sweden. Relevant pharmacokinetic studies for three types of nicotine-containing products (cigarettes, smokeless tobacco, and nicotine replacement products) were analyzed for bioavailable nicotine. Estimates of nicotine intake from each category were made. These were then multiplied by the amount consumed in the respective countries. Tobacco consumption statistics were usually from official records of taxed sales. In Sweden about 54% of all nicotine intake comes from smoked sources, 45% from nonsmoked tobacco, and 1.3% from nicotine replacement products. For men, 63% of the nicotine consumed comes from nonsmoked tobacco. Per-capita nicotine intake per year for adults aged 15 years or older is 3,321 mg for Austria, 3,043 mg for Sweden, 3,014 mg for Denmark, 2,955 mg for the United States, 2,244 mg for Norway, and 2,023 mg for Finland. Compared with cigarette smokers, snus users seem to have a somewhat higher daily intake (34 mg vs. 25 mg). The cleanest nicotine products, nicotine replacement products, represent a negligible part (about 1%) of the total nicotine consumption in most countries.     

Determination of 14 polycyclic aromatic hydrocarbons in mainstream smoke from U.S. brand and non-U.S. brand cigarettes

Tobacco smoke contains thousands of chemical compounds, including many carcinogenic polycyclic aromatic hydrocarbons (PAHs). To determine the concentration ranges of PAHs in tobacco smoke and to understand what factors alter their levels, we quantitatively measured 14 PAHs in mainstream smoke from a transnational U.S. brand (Marlboro) and from locally popular brand cigarettes from 14 countries. We used standardized machine smoking conditions (35-mL puff volume, 60-s puff interval, and 2-s puff duration), extraction of total particulate matter from the Cambridge filters, and gas chromatography/mass spectrometry detection. Deliveries of total PAHs in mainstream smoke of local brands were statistically significantly higher (p < 0.01) than Marlboros in seven countries. In four countries, Marlboro cigarettes had mainstream smoke total PAH levels that were statistically significantly higher (p < 0.01) than local brands. In the remaining three countries, the differences in PAH levels were not statistically significant. Under standard machine smoking conditions, PAH levels were negatively correlated with cigarette filter ventilation levels. We found that several local brands containing primarily flue-cured tobacco filler had relatively high mainstream smoke PAH deliveries, in agreement with findings by previous researchers that flue-cured tobacco typically delivers more PAHs than other tobacco types. We also observed that PAHs were inversely correlated with total carcinogenic tobacco-specific nitrosamines and nitrate content, but these correlations were not statistically significant at the 95% confidence interval. The findings suggest that tobacco blend and nitrate levels may influence PAH deliveries, but other factors may confound this relation.     

甘油施加比例对加热卷烟水分、烟碱和甘油分布的影响

目的：优化加热卷烟烟草薄片的工艺参数。方法：制备了甘油添加比例为5%~30%的12个梯度等级的加热卷烟烟草薄片,制成加热卷烟烟支。使用GC-TCD方法检测加热卷烟烟气、滤嘴冷凝段和烟芯段中水分、烟碱和甘油质量,分析主要成分的质量分布特点,以及释放率、截留率和转移率。结果：加热卷烟烟草薄片在5%~30%甘油添加比例下,水分释放率较高为88.6%~92.3%,主要分布在烟气和滤嘴冷凝段;烟碱释放率次之,为25.5%~34.2%,主要分布在滤嘴冷凝段和烟芯段;甘油释放率最低,为13.9%~21.3%,主要分布在烟芯段。结论：当烟草薄片选择10%~18%的甘油添加比例时,加热卷烟的烟碱和甘油具有较高的转移率和较低的截留率。     

Brand differences of free-base nicotine delivery in cigarette smoke: the view of the tobacco industry documents

The recent availability of internal tobacco industry documents provides significant insight into industry knowledge and manipulation of tobacco smoke delivery. One critical area of research is the role of smoke chemistry in determining the absorption and effects of smoke constituents, especially harm producing or pharmacologically active compounds. Independent scientific research has suggested that the nicotine dosing characteristics, hence the addiction potential of cigarettes, may be determined in part by the amount of free‐base nicotine in cigarette smoke and its effects on the location, route, and speed of absorption in the body and on the sensory perception effects of the inhaled smoke. Tobacco industry documents describe the use of a number of methods internally for measuring free‐base nicotine delivery. These include the common use of cigarette “smoke pH” as a means to estimate the fraction of free‐base nicotine in the particulate matter (PM) in cigarette smoke, as well as efforts to measure free‐base nicotine directly. Although these methods do not provide accurate absolute measures of free‐base nicotine in smoke, consistencies observed in the findings across the various manufacturers indicate: (1) real relative differences in the acid/base chemistry of the smoke from different brands of cigarettes; (2) a connection between differences in free‐base levels and brand‐dependent differences in sensory perception and smoke “impact”; and (3) levels of free‐base nicotine that are greater than have typically been publicly discussed by the industry. Furthermore, the results of these methods are generally consistent with those of a recent study from the Centers for Disease Control and Prevention which directly measured the free‐base fraction of nicotine across a range of cigarette types. Consideration of the likely fundamental importance of free‐base nicotine levels in cigarette smoke, together with the efforts discussed in the tobacco industry documents to measure such levels, indicates that the public health community would benefit from additional research to assess directly the delivery of free‐base nicotine in cigarette smoke across brands. This may be especially useful for those products (“light”, “ultralight”, “reduced carcinogen”, etc) that have been promoted, either explicitly or implicitly, as “harm reducing”.     

Filter ventilation and nicotine content of tobacco in cigarettes from Canada, the United Kingdom, and the United States

OBJECTIVES: The purpose was to determine filter ventilation and the nicotine content of tobacco and their contribution to machine-smoked yields of cigarettes from the United States, Canada, and the United Kingdom. METHODS: Ninety-two brands of cigarettes (32 American, 23 Canadian, and 37 British brands) were purchased at retail outlets in State College, Pennsylvania, United States, Toronto, Canada, and London, United Kingdom. A FIDUS FDT filter ventilation tester measured the percentage air-dilution from filter vents. High-pressure, liquid chromatography was used to measure the nicotine content of tobacco. Regression techniques were used to examine the contributions of tobacco nicotine content and filter ventilation to machine-smoked yields of tar, nicotine, and carbon monoxide (CO). RESULTS: Ninety-four per cent of the American brands, 91% of the Canadian brands, and 79% of British brands were ventilated. The total nicotine content of tobacco and percent nicotine (by weight of tobacco) averaged 10.2 mg (standard error of the mean (SEM) 0.25, range: 7.2 to 13.4) and 1.5% (SEM 0.03, range 1.2 to 2) in the United States, 13.5 mg (SEM 0.49, range: 8.0 to 18.3) and 1.8% (SEM 0.06, range: 1.0 to 2.4) in Canada, 12.5 mg (SEM 0.33, range: 9 to 17.5) and 1.7% (SEM 0.04, range: 1.3 to 2.4) in the United Kingdom. Multiple regression analyses showed that ventilation was by far the largest factor influencing machine-smoked yields of tar, nicotine, and CO. CONCLUSION: Filter ventilation appears to be the predominant method for reducing machine-smoked yields of tar, nicotine, and CO in three countries. However, some brands contain about twice as much nicotine (total content or percent nicotine) as do others, indicating that tobacco types or blends and tobacco castings can be used to manipulate nicotine content and nicotine delivery of cigarettes.     

Determination of carcinogenic tobacco-specific nitrosamines in mainstream smoke from U.S.-brand and non-U.S.-brand cigarettes from 14 countries.

Tobacco-specific nitrosamines (TSNAs) comprise one of the major classes of carcinogenic compounds in mainstream cigarette smoke. As part of collaborative efforts between the World Health Organization and the U.S. Centers for Disease Control and Prevention (CDC) to reduce tobacco use and resulting disease, the CDC examined carcinogenic TSNA levels from cigarettes obtained from selected countries around the world. Using a modern, high-throughput liquid chromatography/mass spectrometry/mass spectrometry method under stringent quality control protocols, we determined the carcinogenic TSNA levels in mainstream smoke from a globally marketed brand, Marlboro, and from local top-selling cigarette brands from 14 countries. The levels of carcinogenic TSNAs in mainstream smoke collected using a 35-ml puff volume, 60-s puff interval, and 2-s puff duration correlated well (R=0.79, p<.0001) with previously reported levels in the corresponding tobacco filler. Marlboro cigarettes purchased in 10 countries had significantly higher carcinogenic TSNA levels in mainstream smoke than did local-brand cigarettes from the same country. In only one country, Brazil, were the carcinogenic TSNA levels in mainstream smoke from Marlboro cigarettes significantly lower than in the locally popular brand. However, carcinogenic TSNA levels in mainstream smoke from Brazilian Marlboro cigarettes were usually lower than those in mainstream smoke from the Marlboros purchased in the other 13 countries, suggesting a reason for the difference. The wide range of mainstream smoke carcinogenic TSNA levels measured in the present study (8.7-312 ng/cigarette) suggest that manufacturers can lower the carcinogenic TSNA levels and that, for similar filter ventilation, carcinogenic TSNA levels in the tobacco filler of a cigarette are a useful indicator of the corresponding levels in mainstream smoke.     

Photoprotective effect of mycosporine-like aminoacids extracts on natamycin,saffron carotenoids and epigallocatechin gallate in acidified beverages exposed to different light sources

Natamycin has been used as a natural food additive to control the growth of many microorganisms. However, this polyene is very sensitive to light exposure. Therefore, the objective of this study was to evaluate the photoprotective effect of mycosporine-like aminoacids (MAA) in acidified beverages containing natamycin, epigallocatechin gallate (EGCG), and saffron carotenoids (SC) stored in three conditions: fluorescent, low and high intensity Light-Emitting Diode (LED) light. Crude MAA extract addition resulted in faster degradation of natamycin, EGCG, and SG. Even in the presence of EDTA-Na, there was higher degradation of natamycin in the presence of MAA extracts. Purification of the MAA extracts using solid-phase extraction (SPE) resulted in slight, but significantly better retention of natamycin under fluorescent and low LED lighting; this was not seen at high LED, however. Therefore, purified MAA extract expressed a potential photoprotective effect on natamycin in acidified beverages.     

超高效液相色谱-高分辨质谱法同时测定鱼肉中16种全氟烷基化合物

基于超高效液相色谱-质谱（ultra-high performance liquid chromatography-mass spectrometry,UPLC-MS/MS）定量方法以及多指标综合评价方法,对刺五加多组分超声提取工艺进行优化。开发UPLC-MS/MS定量方法,同时测定刺五加多组分（绿原酸、紫丁香苷、刺五加苷E、异嗪皮啶、咖啡酸、芝麻素）含量;再由层次分析法（analytic hierarchy process,AHP）及熵权法（entropy weight method,EWM）组建多指标综合评价方法—层次分析-熵权法（AHP-EWM）;最终由单因素结合基于Box-Behnken设计（Box-Behnken design,BBD）的响应面法（response surface methodology,RSM）优化刺五加多组分超声提取工艺。结果表明,RSM优化所得刺五加多组分超声提取最佳工艺：超声功率780 W,超声时间17.5 min,乙醇体积分数57%,料液比1:40 g:mL,原料粒径80目。由此,刺五加根茎中绿原酸、紫丁香苷、刺五加苷E、异嗪皮啶、芝麻素的含量分别为2235.841±12.17、517.959±6.09、861.247±5.30、66.657±1.22、45.745±0.77、99.355±0.69 μg/g,且基于AHP-EWM所得的综合得分为95.45±0.39,与预测理论值接近。刺五加定量分析方法与高效提取工艺的有效开发,为其资源利用以及药效基础研究奠定基础。     

Secondhand smoke levels in Scottish pubs: the effect of smoke-free legislation

Objective

To compare levels of particulate matter, as a marker of secondhand smoke (SHS) levels, in pubs before and 2 months after the implementation of Scottish legislation to prohibit smoking in substantially enclosed public places.

Design

Comparison of SHS levels before and after the legislation in a random selection of 41 pubs in 2 Scottish cities.

Methods

Fine particulate matter <2.5 μm in diameter (PM_2.5) was measured discreetly for 30 min in each bar on 1 or 2 visits in the 8 weeks preceding the starting date of the Smoking, Health and Social Care (Scotland) Act 2005 and then again 2 months after the ban. Repeat visits were undertaken on the same day of the week and at approximately the same time of the day.

Results

PM_2.5 levels before the introduction of the legislation averaged 246 μg/m³ (range 8–902 μg/m³). The average level reduced to 20 μg/m³ (range 6–104 μg/m³) in the period after the ban. Levels of SHS were reduced in all 53 post‐ban visits, with the average reduction being 86% (range 12–99%). PM_2.5 concentrations in most pubs post‐ban were comparable to the outside ambient air PM_2.5 level.

Conclusions

This study has produced the largest dataset of pre‐ and post‐ban SHS levels in pubs of all worldwide smoke‐free legislations introduced to date. Our results show that compliance with the Smoking, Health and Social Care (Scotland) Act 2005 has been high and this has led to a marked reduction in SHS concentrations in Scottish pubs, thereby reducing both the occupational exposure of workers in the hospitality sector and that of non‐smoking patrons.Public health policy in a growing number of countries has moved to control non‐smokers'' exposure to secondhand smoke (SHS), with recent legislation introduced in Ireland, Italy, Spain and Norway. The Smoking, Health and Social Care (Scotland) Act 2005 to ban smoking in substantially enclosed public places was implemented on 26 March 2006 with the aim of protecting non‐smokers from the health effects of SHS.¹A recent review of occupational exposure to SHS suggested that workers in the hospitality sector have among the highest exposures to SHS of all occupational groups.² Data on exposure to SHS across a wide range of entertainment establishments indicated that airborne nicotine concentrations were up to 18.5 times higher than in offices or domestic residences.³ Studies have shown that non‐smoking bar workers have salivary cotinine levels four times those of non‐smokers who live with partners who smoke.⁴ Data from New Zealand indicate that non‐smoking hospitality workers in establishments that permit smoking have salivary cotinine levels between 3 and 4 times those of non‐smoking workers in smoke‐free premises.⁵ One estimate indicates that between 1500 and 2000 non‐smokers'' deaths per year in Scotland can be attributed to SHS exposure.⁶ It has been suggested that SHS exposure may lead to the deaths of over 50 hospitality sector workers in the UK each year.⁷The introduction of smoke‐free legislation in other countries has been shown to dramatically reduce SHS levels. A recent analysis of the effect of the Norwegian legislation⁸ showed that total dust levels in 13 bars and restaurants reduced from an average level of 262 to 77 μg/m³, a 70% reduction, whereas a study in the USA indicated that respirable dust levels in a selection of 8 hospitality venues reduced to approximately 9% of the pre‐ban level.⁹ Similar work in New York State in a mixture of bars and restaurants measured levels of particulate matter <2.5 μm in diameter (PM_2.5), and found that mean levels decreased from 412 to 27 μg/m³ (93.5%).¹⁰ Mulcahy et al¹¹ measured changes in airborne nicotine levels as a result of the Irish smoking ban. Their study of 20 pubs showed nicotine reductions of approximately 83%.Although there are currently no air quality standards for PM_2.5 in the UK, both the US Environmental Protection Agency (EPA) and the World Health Organization (WHO) have issued air quality guidance for outdoor air pollution levels measured in PM_2.5.^12,13 The US EPA air quality guidance is divided into bands, and for PM_2.5 these bands are arranged at cut points of <15.4 μg/m³ (good), 15.5–40.4 μg/m³ (moderate), 40.5–65.4 μg/m³ (unhealthy for sensitive groups), 65.5–150.4 μg/m³ (unhealthy), 150.5–250.4 μg/m³ (very unhealthy) and >250.5 μg/m³ (hazardous). The US EPA standard for PM_2.5 has a 24 h averaged target of 65 μg/m³, with an annualised average of 15 μg/m³. The WHO recently revised its outdoor air quality guidance and now recommends a 24 h average limit of 25 μg/m^3, with an annual average not exceeding 10 μg/m³ measured in PM_2.5.¹³This paper describes our methods of measurement of SHS concentrations in a selection of Scottish pubs and examines the changes in SHS levels that occurred as a result of the implementation of the ban on 26 March 2006. It forms part of a comprehensive evaluation strategy to measure the effects of the introduction of the Scottish smoke‐free legislation.¹⁴     

Melanin and nicotine: A review of the literature.

The role of melanin in nicotine uptake and metabolism has received little attention. Because nicotine has been shown to accumulate in tissues containing melanin, exploring links between melanin and nicotine may provide additional clues to understanding smoking behavior and disease effects. To examine the scientific literature on the relationship between melanin and nicotine, we conducted a PubMed search. We also searched online archives of internal tobacco industry documents. We retrieved and reviewed 82 published research papers related to melanin and nicotine or melanin and metabolism of other drugs, and 150 relevant internal tobacco industry documents. The published literature suggests that nicotine may accumulate in human tissues containing melanin and this retention may increase melanin synthesis. Existing research on the relationship between melanin and nicotine lacks an adequate consideration of this relationship's potential impact, if any, on nicotine metabolism, level of nicotine dependence, and ability to quit smoking. Differential accumulation of nicotine in melanin-containing tissues could have implications for individuals with high levels of melanin.