publications

Comparison of carcinogen, carbon monoxide, and ultrafine particle emissions from narghile waterpipe and cigarette smoking: Sidestream smoke measurements and assessment of second-hand smoke emission factors
Atmospheric Environment (2009), doi:10.1016/j.atmosenv.2009.10.004
N. Daher, R. Saleh, E. Jaroudi, H. Sheheitli, T. Badr, E. Sepetdjian, M. Al Rashidi, N. Saliba, A. Shihadeh

Abstract – The lack of scientific evidence on the constituents, properties, and health effects of second-hand waterpipe smoke has fueled controversy over whether public smoking bans should include the waterpipe. The purpose of this study was to investigate and compare emissions of ultrafine particles (UFP, <100 nm), carcinogenic polyaromatic hydrocarbons (PAH), volatile aldehydes, and carbon monoxide (CO) for cigarettes and narghile (shisha, hookah) waterpipes. These smoke constituents are associated with a variety of cancers, and heart and pulmonary diseases, and span the volatility range found in tobacco smoke. Sidestream cigarette and waterpipe smoke was captured and aged in a 1 m3 Teflon-coated chamber operating at 1.5 air changes per hour (ACH). The chamber was characterized for particle mass and number surface deposition rates. UFP and CO concentrations were measured online using a fast particle spectrometer (TSI 3090 Engine Exhaust Particle Sizer), and an indoor air quality monitor. Particulate PAH and gaseous volatile aldehydes were captured on glass fiber filters and DNPH-coated SPE cartridges, respectively, and analyzed off-line using GC–MS and HPLC–MS. PAH compounds quantified were the 5- and 6-ring compounds of the EPA priority list. Measured aldehydes consisted of formaldehyde, acetaldehyde, acrolein, methacrolein, and propionaldehyde. We found that a single waterpipe use session emits in the sidestream smoke approximately four times the carcinogenic PAH, four times the volatile aldehydes, and 30 times the CO of a single cigarette. Accounting for exhaled mainstream smoke, and given a habitual smoker smoking rate of 2 cigarettes per hour, during a typical one-hour waterpipe use session a waterpipe smoker likely generates ambient carcinogens and toxicants equivalent to 2–10 cigarette smokers, depending on the compound in question. There is therefore good reason to include waterpipe tobacco smoking in public smoking bans.

Determination of evaporation coefficients of semi-volatile organic aerosols using an integrated volume—tandem differential mobility analysis (IV-TDMA) method
Journal ofAerosolScience (2009),doi:10.1016/j.jaerosci.2009.09.008
R. Saleh, A. Shihadeh, and A. Khlystov

Abstract – We present the integrated volume--tandem differential mobility analysis method for determining evaporation coefficients of semi-volatile aerosols. This thermodenuder-based method allows separate determination of the three parameters governing aerosol evaporation, namely, saturation pressure, surface free energy and evaporation coefficient. Saturation pressure is determined by measuring particle volume changes as the aerosol passes through equilibrium states, while evaporation coefficient and surface free energy are determined by fitting particle evaporation rates measured under non-equilibrium conditions to a numerical model of the evaporation process. Evaporation coefficient is determined in a size range where surface free energy effects are negligible, allowing for single parameter optimization. We demonstrate the technique by applying it to dicarboxylic acid aerosols which are pertinent to atmospheric chemistry problems. We obtained evaporation coefficients and surface free energy values of 0.07±0.02 and 0.15±0.07, 0.08±0.02 and 0.17±0.12 and 0.24±0.04 and 0.23 ±0.08 J/m2 for succinic, adipic, and pimelic acids, respectively.

Waterpipe Tobacco and Cigarette Smoking: Direct Comparison of Toxicant Exposure
American Journal of Preventive Medicine, in press (2009)
T. Eissenberg and A. Shihadeh

Abstract – Waterpipe (hookah, shisha) tobacco smoking has spread worldwide. Many waterpipe smokers believe that, relative to cigarettes, waterpipes are associated with lower smoke toxicant levels and fewer health risks. For physicians to address these beliefs credibly, waterpipe and cigarette must be compared directly. Participants (N=31; mean=21.4 years, SD=2.3) reporting monthly waterpipe use (mean=5.2 uses/month, SD=4.0) and weekly cigarette smoking (mean 9.9 cigarettes/day, SD=6.4) completed a crossover study in which they each smoked a waterpipe for a maximum of 45 minutes or a single cigarette. Outcomes included expired air carbon monoxide (CO) 5 minutes after session’s end, and blood carboxyhemoglobin (COHb), plasma nicotine, heart rate, and puff topography. CO increased, on average, by 23.9 ppm for waterpipe (SD=19.8) and 2.7 ppm for cigarette (SD=1.8) while peak waterpipe COHb levels (mean=3.9%, SD=2.5) were three times those observed for the cigarette (mean=1.3%, SD=0.5; Ps<0.001). Peak nicotine levels did not differ (mean ng/ml waterpipe=10.2, SD=7.0; cigarette=10.6, SD=7.7). Significant heart rate increases relative to pre-smoking were observed 5, 10, 15, 20, 25, and 35 minutes during the cigarette session and at every 5 minute interval during the waterpipe session (Ps<0.001). Mean total puff volume was 48.6 liters for waterpipe as compared to 1.0 liters for cigarette (P<0.001). Relative to a cigarette, waterpipe use is associated with greater CO, similar nicotine, and dramatically more smoke exposure. Physicians can inform patients that these tobacco smoking methods expose them to some of the same toxicants.

Volatile aldehydes in the mainstream smoke of the narghile waterpipe
Food and Chemical Toxicology, Volume 46, Issue 11, November 2008, Pages 3546-3549
M. Al Rashidi, A. Shihadeh, N.A. Saliba

Abstract –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 ma’ssel 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, 2.6 s puff duration and 17 s inter puff interval, the average yields of formaldehyde, acetaldehyde, acrolein, propionaldehyde and methacrolein were 630, 2520, 892, 403, and 106 lg/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 _ 10_8 lg/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.

Charcoal emissions as a source of CO and carcinogenic PAH in mainstream narghile waterpipe smoke
Food and Chemical Toxicology, Volume 46, Issue 9, September 2008, Pages 2991-2995
B. Monzer, E. Sepetdjian, N. Saliba, A. Shihadeh

Abstract –Burning charcoal is normally placed atop the tobacco to smoke the narghile waterpipe. We investigated the importance of charcoal as a toxicant source in the mainstream smoke, with particular attention to two well-known charcoal emissions: carbon monoxide (CO) and polyaromatic hydrocarbons (PAH). CO and PAH yields were compared when a waterpipe was machine smoked using charcoal and using an electrical heating element. The electrical heating element was designed to produce spatial and temporal temperature distributions similar to those measured using charcoal. With a popular type of ma’assel tobacco mixture, and using a smoking regimen consisting of 105 puffs of 530 ml volume spaced 17 s apart, it was found that approximately 90% of the CO and 75–92% of the 4- and 5-membered ring PAH compounds originated in the charcoal. Greater than 95% of the benzo(a)pyrene in the smoke was attributable to the charcoal. It was also found that the relative proportions of individual PAH species, the ‘‘PAH fingerprint”, of the mainstream smoke were highly correlated to those extracted from the unburned charcoal (R2 > 0.94). In contrast, there was no correlation between the PAH fingerprint of the electrically heated and charcoal-heated conditions (R2 < 0.02). In addition to inhaling toxicants transferred from the tobacco, such as nicotine, ‘‘tar”, and nitrosamines, waterpipe smokers thus also inhale large quantities of combustion- generated toxicants. This explains why, despite the generally low temperatures attained in the narghile tobacco, large quantities of CO and PAH have been found in the smoke.

Elevated toxicant yields with narghile waterpipes smoked using a plastic hose
Food and Chemical Toxicology, Volume 46, Issue 5, May 2008, Pages 1461-1466
R. Saleh and A. Shihadeh

Abstract –The effect of hose permeability on toxicant yields for the narghile waterpipe is investigated with special reference to the recent adoption of plastic as a hose construction material. Measurements of air infiltration rates for 23 leather and plastic hoses representing 11 types commonly available in Beirut, Lebanon were made, revealing that while leather hoses allowed significant outside air infiltration during a puff – constituting up to 32% of the puff volume – plastic hoses were found to be air-tight, indicating that the smoke reaching the waterpipe user can be considerably more concentrated when delivered via a plastic hose. Total particulate matter (TPM), nicotine and carbon monoxide (CO) yields were compared when a waterpipe was machine smoked using a highly permeable leather and an air-tight plastic hose. It was found that the plastic hose resulted in similar yields of nicotine, but more than double the CO yielded with the highly permeable leather hose. Thus, even if narghile smokers titrate for nicotine intake, the use of a plastic hose will likely greatly increase exposure to CO, a major causative agent in cardiovascular disease.

Measurement of 16 polycyclic aromatic hydrocarbons in narghile waterpipe tobacco smoke
Food and Chemical Toxicology, Volume 46, Issue 5, May 2008, Pages 1582-1590
E. Sepetdjian, A. Shihadeh, and N. Saliba

Abstract–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 2.6 s duration spaced 17 s 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 and 96 ng for benzo[a]pyrene and indeno[123-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.

Comparison of trip average in-vehicle and exterior CO determinations by continuous and grab sampling using an electrochemical sensing method
Atmospheric Environment, Volume 41, Issue 28, 2007
L. Abi Esber, M. El-Fadel, A. Shihadeh

Abstract–In air quality monitoring studies, continuous sampling is capable of reflecting real time variation of gas levels, however, with a margin of uncertainty related to the response time of the sensor and to the speed of concentration fluctuation. In contrast, grab sampling allows the determination of average gas concentration over the whole sampling period eliminating thus the uncertainties associated with the continuous method. As studies of in-vehicle carbon monoxide (CO) exposure often show rapidly fluctuating CO levels and are increasingly using the continuous electrochemical sensing method, the present activity aims at validating the suitability of the latter method for this monitoring task. For this purpose, an electrochemical CO sensing monitor was used to continuously monitor CO level inside and outside of a vehicle moving in an urban area, and to analyze the content of concomitantly taken grab samples. Trip-average CO levels measured using the two testing methods were compared. For CO levels higher than the instrument detection limit (1 ppm), the observed percent difference between continuous and grab sampling results varied within a fairly acceptable range (0.6–15.4%). The regression of continuous sampling data against grab sampling data revealed an average error of 6.9%, indicating the suitability of the continuous electrochemical method for monitoring in-vehicle and exterior average CO concentration under typical urban traffic conditions.

In situ carbon monoxide, “tar,” and topography measurements for 20 narghile waterpipe smokers in natural settings using a novel smoke sampling device
M. Katurji and A. Shihadeh
13th Annual Meeting of the SRNT, Austin, Tx, February 2007

Abstract -This study reports in situ measurements of CO and “tar” intake of 20 narghile waterpipe smokers in Beirut cafés and homes using a novel real-time smoke sampling/topography instrument. Whenever a smoker draws a puff, approximately 2% the smoke is proportionally sampled from a special mouthpiece by a computer-controlled miniature pump. The sample passes through a particulate trap and into a Teflon bag for off-line chemical analysis. The instrument has been validated by attaching it to a laboratory waterpipe smoking machine and comparing mainstream and sampled smoke composition. By sampling the smoke as it is generated by real smokers in their natural settings, difficulties associated with reproducing smoker idiosyncrasies in laboratory smoking machine studies are avoided. Using this instrument, a pilot study was conducted in two cafés (n = 11 participants, 10 men, mean age = 27), and homes (n = 9 participants, 5 men, mean age = 24) in Beirut, Lebanon. The objectives of this study were to measure toxicant intake and smoker topography of waterpipe tobacco (ma’assel) smokers in their natural settings, and to compare these to previous toxicant yield data derived using a laboratory smoking machine. Results showed that smokers inhaled 111.4±0.11 milligrams CO (mean±standard error) and 350±120 milligrams “tar”. Mean smoking time, puff duration, interpuff interval, number of puffs, puff volume, and total inhaled smoke volume were 48±1.6 minutes, 2.8±0.06 seconds, 15.2±0.59 seconds, 178±9.4 puffs, 0.59±0.02 liters, and 95.6±4.7 liters, respectively. Inhaled CO and “tar” increased monotonically with smoked volumes (R-square of 0.58 and 0.64), with an average slope of 1.2 and 3.7 milligrams/liter respectively. These data are comparable to previous smoking machine study data, and confirm that - contrary to the widespread perception that the water bubbler renders the smoke safe for consumption - CO and “tar” intakes by narghile waterpipe smokers during a single use session are many times greater than those associated with a single cigarette.

Hygroscopic growth and evaporation in an aerosol with boundary heat and mass transfer
Journal of Aerosol Science, Volume 38, Issue 1, January 2007, Pages 1-16
R. Saleh and A. Shihadeh

Abstract –This study demonstrates an experimental method for using temperature measurements as a means for validating computations of particle size distribution in a growing or evaporating high-concentration aerosol flowing in a tube with wall heat and mass transfer. The method is based on the premise that aggregate growth or condensation from an ensemble of aerosol droplets can be inferred by comparing temperature evolution of an aerosol-laden and aerosol-free flow through a heated or cooled tube. The difference in bulk temperature is used as an indicator of latent heat effect which is directly related to condensational and evaporative particle size changes. Dimensional analysis is used to derive the conditions under which such an approach can be used. Two parameters, the “coupling number” and the dimensionless mass concentration are found to govern the sensitivity of continuous phase temperature to aggregate evaporation or condensation of the droplet ensemble, and the sensitivity of temperature to droplet diameter changes, respectively. Experimental data for an aqueous saline aerosol flowing through a heated, constant wall temperature tube are presented and compared to predictions derived using a Lagrangian plug-flow model with a fully moving particle bin structure. Measured and predicted bulk phase temperatures agree to within 3%. Using sensitivity analysis, it is shown that hygroscopic particle diameter changes will be at least as accurate.

Effect of smoke CO concentration and overall puff duration on CO boost in waterpipe smokers: direct evidence linking toxicant exposure and uptake
A. Shihadeh, S. Rustom, M. Katurji, W. Maziak, T. Eissenberg, K. Ward
World Conference on Tobacco OR Health, Washington DC, July 2006

Abstract -Despite its long history and widespread use, only recently have methods begun to be developed for studying waterpipe smoke chemistry. Using a “best estimate” waterpipe machine smoking method, a recent study found that a single smoking session yields staggering quantities of carbon monoxide. Given the tentative stage of waterpipe testing methods, the current study objectives were: 1) to validate whether the current machine smoking laboratory protocol (Shihadeh and Saleh, 2005) yields realistic levels of smoke CO, and 2) to determine whether smoke CO concentration indicates CO uptake by smokers, and how this depends on smoking topography parameters. A novel instrument was developed to simultaneously measure smoking topography and sample the inhaled smoke. It was attached to the waterpipes of 14 volunteers in a clinic in Aleppo, Syria. Participants were free to prepare and smoke a waterpipe using any method they choose. At the end of a smoking session, the sampled smoke was analyzed for CO concentration. Expired air CO was measured before and after each waterpipe use session to determine CO boost. CO boost in smokers ranged from 2-53 ppm (median boost = 13 ppm). The data showed that the higher the smoke CO concentration and the longer the overall puff duration, the greater the CO boost. This can be regarded as definitive evidence that users absorb the CO present in waterpipe smoke in a dose dependent manner. We also found that the smoking machine method results in a smoke CO concentration consistent with that of in vivo smokers.

 

Waterpipe tobacco smoking: health effects, research needs, and recommended action by regulators Advisory Note by the WHO Study Group on Tobacco Product Regulation, 2005 Tobacco smoking using a waterpipe: product, prevalence, chemistry/toxicology, pharmacological effects, and health hazards A monograph prepared for The WHO Study Group on Tobacco Product Regulation [document]

Polycyclic aromatic hydrocarbons, carbon monoxide, “tar”, and nicotine in the mainstream smoke aerosol of the narghile water pipe
Food and Chemical Toxicology, Volume 43, Issue 5, May 2005
Shihadeh, A. and Saleh, R.

Abstract - A smoking machine protocol and yields for “tar”, nicotine, PAH, and CO are presented for  the standard 171-puff steady periodic smoking regimen proposed by Shihadeh et al (2004).  Results show that smokers are likely exposed to more “tar” and nicotine than previously thought, and that pyronsynthesized PAH are present in the “tar” despite the low temperatures characteristic of the tobacco in narghile smoking.  With a smoking regimen consisting of 171 puffs each of 0.53 l volume and 2.6 s duration with a 17 s interpuff interval, the following results were obtained for a single smoking session of 10 g of mo’assel tobacco paste with 1.5 quick-lighting charcoal disks applied to the narghile head: 2.94 mg nicotine, 802 mg “tar”, 145 mg CO, and relative to the smoke of a single cigarette, greater quantities of chrysene, phenanthrene, and fluoranthene.  Anthracene and pyrene were also identified but not quantified.  The results indicate that narghile smoke likely contains an abundance of several of the chemicals thought to be causal factors in the elevated incidence of cancer, cardiovascular disease and addiction in cigarette smokers.

Size distribution dynamics of a hygroscopic aerosol flowing through an isothermal wall tube with coupled heat and mass transfer: modeling and experimental validation [poster]
Poster presentation at the 24th Annual AAAR Conference, Austin, Tx, October 2005
Alan Shihadeh* and Rawad Saleh

Abstract - We present an experimental and computational study of a volatile continuum regime polydisperse aerosol flowing through a constant wall temperature tube. Following Finlay and Stapleton (1995) a Lagrangian numerical method for simulating 2-way coupled heat and mass transfer between the aerosol droplets, bulk phase, and tube wall was developed to predict hygroscopic growth or shrinkage. The aerosol particle size distribution is discretized using a moving grid in which each bin is characterized by a single particle volume that is allowed to change in accordance with the coupled heat/mass transfer model. Wall heat and mass transfer is approached using a boundary layer formulation. Computations are compared to experimental data generated with a nebulized saline solution flowing through a heated constant wall temperature tube. The initial size distribution of the nebulized saline particles is determined using the residual method with a QCM cascade impactor. The evolution of the bulk temperature of the aerosol as it travels through the tube is measured for a variety of flow conditions and saline concentrations, and is compared to predictions from the 2-way coupled model. By using bulk-phase temperature as the primary diagnostic, a number of practical difficulties – which have thus far hindered presentation of experimental data for this fundamental problem – associated with analyzing a volatile aerosol are avoided. The experimental setup and data are presented which can be used to validate computational models of flowing hygroscopic aerosols, including Finlay and Stapleton’s 2-way model which has been used to predict hygroscopic particle growth for lung deposition calculations of inhaled aerosols.

A closed-loop control “playback” smoking machine for generating mainstream smoke aerosols
J. Aerosol Medicine, Volume 19, Issue 2, 2006
Shihadeh, A. and Azar, S.

Abstract - A first generation smoking machine capable of reading and replicating detailed puffing behavior from recorded smoking topography data is presented. Unlike standard smoking machines, which model human puffing behavior as a steady periodic waveform with a fixed puff frequency, volume, and duration, this novel machine generates a mainstream smoke aerosol by automatically "playing-back" puff topography recordings. Because combustion chemistry is highly non-linear, representing real smoking behavior with a smoothed periodic waveform may result in a tobacco smoke aerosol with a significantly different chemical composition and physical properties than that generated by a smoker.  The machine presented here utilizes a rapid closed-loop control algorithm coded in Labview® to generate smoke aerosols for toxicological assessment and inhalation studies. To illustrate its use, dry particulate matter and carbon monoxide yields generated using the playback and equivalent periodic puffing regimens are compared for a single smoking session by a 26 year old male narghile water-pipe smoker.  It was found that the periodic puffing regimen yielded 20% less CO than the played-back smoking session, indicating that steady periodic smoking regimens, which are widely used in tobacco smoke research, may not produce realistic smoke aerosols.

Investigation of mainstream smoke aerosol of the argileh water pipe
Food and Chemical Toxicology, Volume 41, Issue 1, January 2003
Alan Shihadeh

Abstract - A first-generation smoking machine and protocol have been developed in order to study the mainstream smoke aerosol and elucidate thermal-fluid processes of the argileh water pipe. Results using a common mo'assel tobacco mixture show that, contrary to popular perceptions, the mainstream smoke contains significant amounts of nicotine, ''tar'' and heavy metals. With a standard smoking protocol of 100 puffs of 3 s duration spaced at 30-s intervals, the following results were obtained in a single smoking session: 2.25 mg nicotine, 242 mg nicotine-free dry particulate matter (NFDPM), and relative to the smoke of a single cigarette, high levels of arsenic, chromium and lead. It was found that increasing puff frequency increased the NFDPM but had little effect on nicotine delivery, while removing the water from the bowl increased by several-fold the nicotine, but had little effect on NFDPM. It was also found that the charcoal disk heat source contributed less than 2% of total particulate matter (TPM), and that characteristic temperatures of the tobacco varied from 450 deg C nearest the heat source to 50 deg C furthest away, indicating that the NFDPM is likely a result of devolatilization rather than chemical reaction, and will thus differ significantly in composition from that of cigarette smoke.

New Research: Narghile Smokers Exposed to Dangerous Chemicals [english] [arabic]
Press Release, February 2003

Two new studies conducted by researchers at the American University of Beirut and St. Joseph University in Beirut show that narghile smoke contains significant quantities of the same chemicals which make cigarette smoke harmful. The findings contradict the commonly held belief that the water of the narghile water pipe renders the smoke harmless

Towards a topographical model of argileh water-pipe café smoking [english]
Pharmacology, Biochemistry and Behavior, Vol 79/1, September 2004
Alan Shihadeh, Sima Azar, Charbel Antonios, Antoine Haddad

Abstract–A pilot study of argileh water-pipe smokers in a café in the Hamra neighborhood of Beirut, Lebanon was conducted in order to develop a preliminary model of argileh water-pipe smoking behavior for use in laboratory smoking machine studies. The model is based on data gathered from smoking sessions of 30 minutes or longer duration from 52 smoker volunteers using a differential pressure puff topography instrument developed for the pulsating, high-flow water-pipe, as well as anonymous visual observations of 56 smokers in the same café. Results showed that the “average” water pipe smoking session consists of 171 530 ml puffs of 2.6 s duration at a frequency of 2.8 p/min. The results indicated that previous toxicological assessment of argileh smoke that assumed a smoking session consisting of 100 300 ml puffs probably underestimated the amount of “tar” and nicotine produced in a single smoking session.

A portable, low-resistance puff topography instrument for pulsating, high flow smoking devices
Behavior Research Methods, Instruments, & Computers, Volume 37, Issue 1, 2005
Alan Shihadeh, Charbel Antonios, Sima Azar

Abstract – A smoking topography instrument appropriate for pulsating high flow rate smoking devices such as the argileh water pipe has been developed and tested. Instrument precision and repeatability was determined using a digitally controlled smoking machine, and the added draw resistance due to the topography instrument was measured over the range of expected puff flow rates. The maximum error in any topography variable was found to be less than 5%. The instrument was successfully demonstrated in a pilot field study of 30 volunteer argileh smokers. The pilot study yielded an average smoker puff volume, duration, and interpuff interval of 0.53 l, 2.47 s, 16.28 s, respectively.