Najat A. Saliba

Measurement of 16 polycyclic aromatic hydrocarbons in narghile waterpipe tobacco smoke.

An analytical method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in the mainstream of narghile smoke is presented. The smoke was generated using a digital waterpipe smoking machine connected to the mouthpiece of a narghile that was loaded with 10 g of a popular flavored tobacco and kept alight with quick-light charcoal briquettes that are commonly used for this purpose. A standard smoking regimen consisting of 171 puffs of 530 ml volume and 2.6s duration spaced 17s apart was used, and the smoke condensates were collected on glass fiber filters. PAHs were extracted with toluene assisted by sonication. For purification, the extract was passed through a silica cartridge and eluted with hexane. The eluent was preconcentrated, reconstituted in acetonitrile, and analyzed using a GC-MS-SICP method. The method showed good selectivity, repeatability, accuracy and sensitivity. The limit of detection ranged from 15 to 96 ng for benzo[a]pyrene and indeno[1,2,3-cd]pyrene, respectively. It was found that a single narghile smoking session delivers approximately 50 times the quantities of carcinogenic 4- and 5-membered ring PAHs as a single 1R4F cigarette smoked using the FTC protocol. The pattern of PAH concentrations suggested that formation pathways differ from those of the cigarette, possibly reflecting the differing combustion conditions of the two smoking devices.

Volatile aldehydes in the mainstream smoke of the narghile waterpipe

Very little is known about the quality and quantity of toxicants yielded by the narghile, a subject of increasing importance as this method of tobacco smoking has become popular all over the world. This study is concerned with the identification and quantification of volatile aldehydes in the gas and particle phases of mainstream narghile smoke generated using a popular type of flavored massel tobacco mixture. These compounds were analyzed based on a modified version of the Environmental Protection Agency compendium method TO-11A. Using a standardized smoking machine protocol consisting of 171 puffs, 2.6s puff duration and 17s inter puff interval, the average yields of formaldehyde, acetaldehyde, acrolein, propionaldehyde and methacrolein were 630, 2520, 892, 403, and 106 microg/smoking session, respectively. The results showed that none of the aldehydes identified in this study are found in the particulate phase of the smoke, except for formaldehyde for which the partitioning coefficient was estimated as Kp = 3.3 x 10(-8) microg/m3. Given previously reported lung absorption fractions of circa 90% for volatile aldehydes, the yields measured in this study are sufficient to induce various diseases depending on the extent of exposure, and on the breathing patterns of the smokers.

Carcinogenic PAH in waterpipe charcoal products.

Because narghile waterpipe (shisha, hooka) smoking normally involves the use of burning charcoal, smoke inhaled by the user contains constituents originating from the charcoal in addition to those from the tobacco. We have previously found that charcoal accounts for most of the polyaromatic hydrocarbons (PAH) and carbon monoxide in the smoke of the waterpipe, both of which are present in alarming quantities. Because charcoal manufacturing conditions favor formation of PAH, it is reasonable to assume that charcoal sold off the shelf may be contaminated by PAH residues. These residues may constitute a significant fraction of the PAH inhaled by the waterpipe user and those in her/his vicinity. We measured PAH residues on three kinds of raw waterpipe charcoal sampled from Beirut stores and cafés. We found that PAH residues in raw charcoal can account for more than half of the total PAH emitted in the mainstream and sidestream smoke, and about one sixth of the carcinogenic 5- and 6-ring PAH compounds. Total PAH content of the three charcoal types varied systematically by a factor of six from the charcoal with the least to the greatest PAH residue. These findings indicate the possibility of regulating charcoal carcinogen content.

Oxidative potential and chemical speciation of size-resolved particulate matter (PM) at near-freeway and urban background sites in the greater Beirut area

To assess particle oxidative potential in the greater Beirut area, size-resolved PM10-2.5, PM2.5-0.25 and PM0.25 samples were collected at near-freeway and urban background sites. Metals and trace elements, including Mn, Cr, Cu, Ba, Mo and Sb, displayed increased levels and crustal enrichment factors at the roadway, indicating their vehicular origin. These elements in addition to Co, V, Ni and Zn were mostly distributed in PM2.5-0.25 and PM0.25 at both sites, with moderate-to-high water-solubility (>30%). The presence of these metals, mainly air toxics, in small size ranges constitutes an added health risk. Of particular concern are elements with strong correlations (R ≥ 0.70) with reactive oxygen species (ROS)-activity, measured by a cellular assay. In PM10-2.5, road dust component Mn and soil-related element Co were highly correlated with ROS-activity. In PM2.5-0.25, vehicular abrasion element Cu and soil-derived component Co were highly associated with ROS-activity. In PM0.25, V and Ni, originating from fuel oil combustion, strongly correlated with ROS formation. ROS-activity displayed a particle-size dependency, with lowest activity associated with PM10-2.5. On a per air volume basis, size-resolved ROS-activity was 1.5-2.8 times greater at the roadside than background location, indicating that exposure to redox-active species may be greatest near the freeway. Size-fractionated PM intrinsic activity (i.e. PM mass-normalized) was comparable at both sites, possibly suggesting a similarity in the sources of ROS-active species. Relative to other urban settings, while the intrinsic redox activity of PM10-2.5 in Beirut is comparable to that measured at an urban site in Los Angeles (LA), its PM0.25-induced ROS-activity is ~2.3-fold greater. Moreover, the intrinsic ROS-activity of ambient PM2.5 in Beirut is comparable to that reported in Milan-Italy, but 3.1-times PM2.5 activity in the heavily-polluted Lahore-Pakistan. Lastly, findings suggest a dominant role of transition metals in generating ROS compared to organic carbon in the LA area.

Phenolic Compounds in Particles of Mainstream Waterpipe Smoke

INTRODUCTION Waterpipe tobacco smoking has in recent years become a popular international phenomenon, particularly among youth. While it has been shown to deliver significant quantities of several carcinogenic and toxic substances, phenols, an important class of chemical compounds thought to promote DNA mutation and cardiovascular diseases, however, has not been studied. Due to the relatively low temperature characteristic of waterpipe tobacco during smoking (i.e., <450 °C), it was hypothesized that phenolic compounds, which form at approximately 300 °C, will be found in abundance in waterpipe smoke. METHODS In this study, phenolic compounds in the particle phase of waterpipe mainstream smoke were quantified. Waterpipe and cigarette mainstream smoke generated using standard methods were collected on glass fiber pads and analyzed using gas chromatography/mass spectroscopy selected ion current profile chromatogram method for quantification. RESULTS We found that relative to a single cigarette, a waterpipe delivers at least 3 times greater quantities of the 7 analyzed phenols (phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol, and hydroquinone). Moreover, phenol derivatives such as methylcatechol, and flavorings such as vanillin, ethyl vanillin, and benzyl alcohol were found in quantities up to 1,000 times greater than the amount measured in the smoke of a single cigarette. CONCLUSION The large quantities of phenols and phenol derivatives in waterpipe smoke add to the growing evidence that habitual waterpipe use may increase the risk of cancer and cardiovascular diseases.

Transport phenomena governing nicotine emissions from electronic cigarettes: Model formulation and experimental investigation

ABSTRACT Electronic cigarettes (ECIGs) electrically heat and aerosolize a liquid-containing propylene glycol (PG), vegetable glycerin (VG), flavorants, water, and nicotine. ECIG effects and proposed methods to regulate them are controversial. One regulatory focal point involves nicotine emissions. We describe a mathematical model that predicts ECIG nicotine emissions. The model computes the vaporization rate of individual species by numerically solving the unsteady species and energy conservation equations. To validate model predictions, yields of nicotine, total particulate matter, PG, and VG were measured while manipulating puff topography, electrical power, and liquid composition across 100 conditions. Nicotine flux, the rate at which nicotine is emitted per unit time, was the primary outcome. Across conditions, the measured and computed nicotine flux were highly correlated (r = 0.85, p < .0001). As predicted, device power, nicotine concentration, PG/VG ratio, and puff duration influenced nicotine flux (p < .05), while water content and puff velocity did not. Additional empirical investigation revealed that PG/VG liquids act as ideal solutions, that liquid vaporization accounts for more than 95% of ECIG aerosol mass emissions, and that as device power increases the aerosol composition shifts towards the less volatile components of the parent liquid. To the extent that ECIG regulations focus on nicotine emissions, mathematical models like this one can be used to predict ECIG nicotine emissions and to test the effects of proposed regulation of factors that influence nicotine flux. Copyright

Road versus roadside particle size distribution in a hot Mediterranean summer--estimation of fleet emission factors.

Particle size distribution at major on-road, roadside, and university-ground sites in Lebanon were studied in summer 2011. In a predominant old traffic fleet, it is shown that calculated PM2.5 mass emission factors (EFs) conform to those of heavy duty vehicles. When compared to roads in California, higher PM2.5 mass but similar particle number EFs are obtained for the average fleet of the on-road sites. This confirms the observed particle size distribution pattern, rich in particles in the accumulation range mainly between 0.425 and 0.675 µm with a prevalent peak at 0.475 µm. Corresponding total particle counts (TC) measured on the roadside are as high as 14,050 particles/cm3 and are up to 67% higher than particle counts measured at the university-ground site. In a hot, dry and humid summer weather with consistent temperature oscillations, particle dispersion is shown to be a function of meteorological factors, mainly the effect of the boundary-layer thickness, with particle counts measured during the morning being around 40% higher than particle counts measured during the afternoon. Implications In a hot and humid Mediterranean summer, high emission factors are associated with an old car fleet. The observed diurnal variation in the particle count is attributed to the change in the thickness boundary layer in summer. In comparison to road sites, the particle size distribution shows the prevalence of larger size particles. Particle counts measured at the roadside sites are at least 20% higher than those of the road sites. The findings call for the reinforcement of local regulations on car age. Furthermore, the high number of particles can cause or aggravate a number of health and ecosystem problems.

Dust episodes in Beirut and their effect on the chemical composition of coarse and fine particulate matter.

Particles captured during dust episodes in Beirut originated from both the African and Arabian deserts. This particular air mixture showed an increase, over non-dust episodes, in particle volume distribution which was mostly noticed for particles ranging in sizes between 2.25 and 5 μm. It also resulted in an increase in average mass concentration by 48.5% and 14.6%, for the coarse and fine fractions, respectively. Chemical analysis of major aerosol components accounted for 93% of fine PM and 71% of coarse PM. Crustal material (CM) dominated the coarse PM fraction, contributing to 39 ± 15% of the total mass. Sea salt (SS) (11 ± 10%) and secondary ions (SI) (11 ± 7%) were the second most abundant elements. In the fine fraction, SI (36 ± 14%) were the most abundant PM constituent, followed by organic matter (OM) (33 ± 7%) and CM (13 ± 2%). Enrichment factors (EF) and correlation coefficients show that biogenic and anthropogenic sources contribute to the elemental composition of particles during dust episodes. This study emphasizes on the role played by the long-range transport of aerosols in changing the chemical composition of the organic and inorganic constituents of urban coarse and fine PM. The chemical reactions between aged urban and dust aerosols are enhanced during transport, leading to the formation of organo-nitrogenated and -sulfonated compounds. Their oligomeric morphologies are further confirmed by SEM-EDX measurements.

A Comparative Review of PM Levels, Sources, and Their Likely Fates in the Eastern Mediterranean Region

This review highlights measurements from a number of studies investigating levels, origins, chemical processes, and health implications of particulate matters (PMs) in the Eastern Mediterranean region. In this region, assessment of PMs is still scarce although several studies from other countries related PMs with cardiovascular and respiratory problems. Field and modeling studies in the Eastern Mediterranean region have shown that PM levels affected by local sources including dust resuspension, industrial activities, marine aerosols, and seasonal dust storms originating from the Arabian and the Saharan deserts. In autumn and spring natural dust increases the levels of crustal and other elements and organic compounds that are adsorbed on dust surfaces. In summer, pollutants are trapped due to land and sea breezes. Hence, the influence of marine aerosols on the levels of inorganic ions in the coarse and fine particles is noticeable. Given the importance of PM chemical composition and particle size distribution on understanding global atmospheric phenomena, it is essential that particle mass closure in this semi-arid region be comprehensively evaluated.

“Juice Monsters”: Sub-Ohm Vaping and Toxic Volatile Aldehyde Emissions

An emerging category of electronic cigarettes (ECIGs) is sub-Ohm devices (SODs) that operate at ten or more times the power of conventional ECIGs. Because carcinogenic volatile aldehyde (VA) emissions increase sharply with power, SODs may expose users to greater VAs. In this study, we compared VA emissions from several SODs and found that across device, VAs and power were uncorrelated unless power was normalized by coil surface area. VA emissions and liquid consumed were correlated highly. Analyzed in light of EU regulations limiting ECIG liquid nicotine concentration, these findings suggest potential regulatory levers and pitfalls for protecting public health.