1. Introduction
The brand L&M is produced by the Philip Morris Company, based in New York, NY, USA. L&M cigarettes are globally available and quite popular in the USA, Latin America, Central and Northern Europe, the Arab World and the Far East and South Asia. In 2013, L&M was ranked the third best-selling international cigarette brand outside the United States and China, with a 2013 shipment volume of 95 billion units [
1].
Philip Morris has expanded its range of products by offering cigarillos listed under the same name as the established cigarette brand L&M. In the European Union, these cigarillos are considerably cheaper than cigarettes of the same brand mainly due to a favorable taxation (e.g., one packet L&M cigarettes, containing 20 cigarettes “red label”, “blue label” or “red without additives” costs 5 EUR compared to 2.20 EUR for a packet of 17 L&M filtered cigarillos). This price edge will enable brand-loyal cigarette smokers to stick to their usual brand despite rising cigarette taxes. This allows them to continue exposing their fellow humans including children to ETS of one brand up to decades. Several studies have shown that especially low-income smokers switch to cheaper brands or reduce consumption when cigarette prices rise [
2,
3]. Inconsistent taxation will counteract this effect. In the present study, we want to investigate whether there are significant differences in the amounts of ETS-associated particulate matter that different types of L&M cigarettes and L&M cigarillos emit. We believe that against the background of inconsistent taxation, these differences would be of public interest.
According to the United States Environmental Protection Agency (EPA) that defines, regulates and categorizes particulate matter (PM) in the National Air Quality Standard for Particulate Matter [
4], PM is the term for a mixture of microscopic solid and liquid matter suspended in the air. Its sources are natural (e.g., fires, volcanic eruptions,
etc.) or human activities (e.g., tobacco smoke, traffic, industrial processes or use of fossil fuels). Particulate matter is categorized into different sizes of the particles. All particles with aerodynamic diameters smaller than 10 μm are inhalable and categorized as PM
10. The fraction of PM
10 with an aerodynamic diameter larger than 2.5 μm is called “inhalable coarse particles”. All particles with an aerodynamic diameter smaller than 2.5 μm are called PM
2.5 or “fine particles”. The fraction of particles with aerodynamic diameters smaller than 1 μm is called PM
1. PM
2.5 includes PM
1, and consequently PM
10 includes PM
1 and PM
2.5. The smaller the particles are, the more deeply they can be inhaled. Particles of the PM
1 fraction can reach the gas exchange regions of the lung and eventually penetrate the bloodstream. Surface area and solubility also determine PM’s toxicity as they limit the extend of gasses and vapors that can be absorbed (e.g., carcinogenic benzopyrenes) permitting their transport into distal lung areas [
5].
Apart from its suitability as a surrogate parameter for ETS-exposure, both long-term and short-term exposure to PM affects human morbidity and mortality, independently of its origin. According to several studies, these PM effects occur in various ways and are dose-dependent [
6,
7,
8,
9,
10,
11,
12,
13,
14,
15]. Many of the harmful effects are probably caused by oxidative stress, inflammation and DNA-damage [
16,
17]. All health effects (e.g., carcinogenesis, cardiovascular diseases,
etc.) can also be attributed to cigarillo consumption. Unfortunately, the level of knowledge about health effects attributed to cigarillo consumption appears to be low. Many cigarillo smokers consider cigarillo smoke less problematic than cigarette smoke as long as they do not directly inhale the mainstream smoke [
18,
19]. We think that ETS-associated PM ought to be considered an independent hazard factor, separately from nicotine, tar, and the many other known harmful compounds of ETS. Anti-smoking legislation cannot be enforced in a non-public environment. However, better information about brand-specific differences in ETS-associated PM could help raise a general awareness.
3. Results and Discussion
The results of our measurements are shown in
Table 3. Statistically significant differences in Cmean PM
2.5 were found for L&M without additives (red) cigarettes, L&M blue cigarettes and L&M cigarillos (red) compared with the 3R4F reference cigarette respectively. Regarding AUC PM
2.5, differences were significant for L&M blue cigarettes and L&M cigarillos (red) compared with the 3R4F as a reference respectively
Figure 4 and
Figure 5. PM
2.5 mean concentration of L&M cigarillos exceeded those of the 3R4F research cigarette by 69%. When comparing the AUC PM2.5 of L&M cigarillos with the 3R4F cigarette, the cigarillos emit an even 3.8 fold higher dosage than the 3R4F cigarettes. Of all tested tobacco products, L&M filtered cigarillos proved to emit highest amounts of both Cmean PM
2.5 and AUC PM
2.5.
Table 3.
Cmean- and AUC-values of PM2.5 fractions.
Table 3.
Cmean- and AUC-values of PM2.5 fractions.
| PM2.5-Values | 3R4F Reference | L&M without Additives (Red) | L&M Blue | L&M Red | L&M Filtered Cigarillo (Red) |
|---|
| Cmean PM2.5 (μg/m3) | 518 ± 161 | 576 ± 166 | 448 ± 154 | 547 ± 153 | 755 ± 259 |
| AUC PM2.5 (μg/m3·s) | 208,214 ± 67,324 | 204,629 ± 55,191 | 152,718 ± 45,183 | 238,098 ± 67652 | 796,909 ± 271710 |
In the present study we want to juxtapose PM2.5 amounts generated by L&M filtered brand cigarettes and L&M filtered brand cigarillos, compared to PM2.5 generated by filtered 3R4F reference cigarettes, using an automatic environmental tobacco smoke emitter and an aerosol spectrometer. We would like to emphasize, however, that we were not primarily interested in the absolute amounts of Cmean and AUC PM2.5. All absolute data remain imprecise, as long as the aerosol spectrometer is not calibrated against ETS. The manufacturer has not done so yet. For this study we used the Grimm manufacturer’s calibration. For future studies, we plan to create a correction factor for ETS, using a gravimetric filter. Our main focus for now lies on the relative results (the statistically significant differences between the different tobacco products). We were successful to demonstrate that the amounts of ETS-associated PM2.5 differ significantly between most varieties of L&M cigarettes and the 3R4F research cigarette respectively, and that L&M filtered cigarillos release considerable amounts of PM excelling those of the L&M cigarettes and the 3R4F cigarettes by far.
Every tobacco product is made of a special tobacco mixture (at the discretion of the company) including additives to ensure its unique flavor. Differences in PM emissions may be due to these production details such as the composition of tobacco, density of the tobacco filling, as well as the design of the tobacco product and addition of substances in order to improve flavor and burning qualities. The amount of cellulose, which is used as a binding substance for machine-made short filler tobacco, may also contribute to the generation of PM. On the other hand, one might assume that structure and length of a filter crucially affect the amount of PM released by a smoked cigarette—and, in fact, our findings suggest a correlation between filter length and measured PM concentration of the tested tobacco products
Table 1 and
Table 3. The filter seems to have a greater effect on PM than tar and nicotine quantities of the tobacco product. Wertz
et al. (2011) call attention to the effects of additives relating to PM [
21]. They demonstrate an increase of toxicants, including PM, depending on the amount of additives admixed to a tobacco product by the manufacturer. As part of the present study, we compared the standard research reference cigarette 3R4F (without additives) and the L&M without additives (red) to the L&M blue Label and L&M red Label (both with additives), but did not find any differences.
Besides the fact that L&M filtered cigarillos being equipped with the smallest filter, the amount of tobacco burned is largest in the cigarillos
Table 1. Hence, L&M filtered cigarillos generate by far the largest amount of PM
2.5 not only as far as Cmean is concerned, but also regarding AUC, the latter taking the extended period of smoking into account. This is an advantage of our chosen approach, using the AUC method and assuming that smokers do not smoke their cigarettes or cigarillos for an exact given period but rather until they are burned down.
A handicap of our method is the standard deviation of about 30% regarding the amounts of CmeanPM
2.5 between individual packs of one brand “
Table 3”. Heterogeneity was lowest in L&M “red” cigarettes (27%). Mechanical non-return valves may have contributed to this weakness of our method. They had to be replaced every time a tobacco product had been smoked down due to the clogging effects caused by the MS. As mentioned above, the aerosol spectrometer has not been calibrated against tobacco smoke, which leads to inexact absolute data. For our future studies, we plan to improve the accuracy of our measured data by means of a correction factor, which has to be generated, using a gravimetric filter. We also noticed an inter-observer variability of about 10%–20% when comparing the Cmean amounts of the 3R4F research cigarette of different projects performed by different students [
20,
22]. However, individual parameters of all tested varieties were normally distributed and the differences between most of the L&M varieties and the research cigarettes respectively were significant. This and the large differences between all cigarettes and the filtered cigarillos support our impression that the reliability of our method is acceptable for this purpose.
One may also ask why we did not follow an internationally accepted smoking protocol to generate our data with an AETSE (e.g., the “ISO machine smoking regime” or the “Canadian intense”) [
18,
23]. In fact, we followed the ISO intense regime [
23] in puff frequency, but used a smaller puff volume tailor-made to the technical requirements of our AETSE. We believe our protocol is reasonable when comparing with the smoking habits of real smokers [
24]. No protocol is arguably able to exactly imitate human smoking behavior with all its inter- and intra-individual variations in a realistic way. All internationally accepted protocols have been heavily criticized [
25] and other research groups have reconsidered and modified parameters as well [
26].
It should be mentioned, though, that our aim was not to imitate real-life conditions. We did not intend to provide absolute PM data for defined situations. We rather wanted to enable a comparison of different brands and tobacco products, using a standardized smoking protocol according to our requirements, an automatic environmental tobacco smoke emitter that works as reliably as possible within our technical possibilities, and a standard research cigarette as a reference.
In recent years, many studies have been conducted to quantify ETS-associated PM
2.5. Measurements in outdoor smoking areas of restaurants showed mean concentrations between 8.32 μg/m
3 and 124 μg/m
3, depending on the number and distance of smokers to the measurement device [
27]. Our own observations on public railway stations showed a comparable PM burden [
28]. Other studies tested concentrations in closed rooms (e.g., the passenger cabin of a car) and documented Cmean from 85 μg/m
3 up to 3850 μg/m
3 [
29]. We believe that specific differences in the amounts of ETS-associated PM do matter, especially when considering that in addition to their inflammatory and immunologic effects, particles may also serve as transporters for low volatile carcinogenic substances such as polycyclic aromatic hydrocarbons or aromatic amines, permitting them access to distal lung areas. Vardavas
et al. recently demonstrated that concentrations of the carcinogenic and tobacco specific 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine correlate with concentrations of PM
2.5 attributable to second-hand smoke [
5]. The scientists therefore examined non-smoking employees in semi-open air cafés in Athens, Greece. They found that NNAL concentrations increased by 9.5%, per 10 μg/m
3 increase in PM
2.5.
We consider ETS-associated PM emissions as an important independent risk factor for passive smokers. While measures to reduce tar and nicotine yield of cigarettes are already legally required in most countries, efforts to reduce PM in environmental tobacco smoke should be undertaken.
