Table 1

Articles obtained from the literature search

Lead authorYearCountryType and number of subjects (or target places)Study designOutcomes measuredSummaryMain findingsExclusion of other sources of second-hand smoke
Cobb et al152013USA28 venues in Virginia (17 waterpipe cafes, 5 restaurants permitting cigarette smoking and 6 smoke-free restaurants (5 with valid data))ObservationalPM with a 2.5 μm aerodynamic diameter or smaller (PM2.5)Waterpipe café smoking rooms have a hazardous level of PM2.5 that could be potentially harmful to customers and workersPM2.5 was greater in waterpipe café smoking rooms (374 μg/m3, n=17) compared with waterpipe café non-smoking rooms, cigarette smoking-permitted restaurant smoking rooms, cigarette smoking-permitted restaurant non-smoking rooms, and smoke-free restaurantsMeasurements began 5 min prior to entering the venue and ended 5 min after exiting each venue to compare outdoor ambient air to the air inside the venue
Daher et al72010Lebanon4 repeated waterpipe-smoking sessions and 4 repeated cigarette trialsObservationalSidestream smoke from waterpipes or cigarettes for ultrafine particles, carcinogenic polyaromatic hydrocarbons, volatile aldehydes, and COSecond-hand waterpipe smoke emits significant harmful substancesSidestream waterpipe smoke had nearly 4 times the carcinogenic PAH, 4 times the volatile aldehydes and 30 times the CO of 1 cigaretteSmoking-machine and environmental chamber approach allowed for repeated measurements under controlled conditions and few confounding variables
Fiala et al142012USA10 indoor hookah lounges in OregonObservationalPM smaller than 2.5 μm in diameterAir quality in hookah lounges in Oregon ranges from unhealthy to hazardous2 hookah lounges had peak PM2.5 measurements in the hazardous EPI air quality category, 4 were very unhealthy, and 4 were unhealthy. None had good air qualityMeasurements began prior to entering the venues and ended after exiting the venues to compare the outdoor ambient air to the air in the hookah lounges
Fini et al122013Iran387 total persons (172 male and 215 female)ObservationalDemographic characteristics and questions related to environmental tobacco smoke exposureA large proportion of citizens of Bandar Abbas city are exposed to environmental tobacco smokeThe most common places that people were exposed to hookah smoke were in the home (93.4%), coffee shops (17.1%) and restaurants (11.5%). People were exposed to environmental cigarette smoke in public vehicles (52.2%) and the home (31.3%)NA
Hammal et al192013Canada3 replicates of each of the 3 brands were analysed. 6 randomly selected waterpipe cafes were visitedObservationalChemical constituents of tobacco-free products used in waterpipes, waterpipe emission under controlled conditions, and air quality markers in waterpipe cafesSecond-hand smoke from herbal shisha contains carcinogens equal to or greater than that found in cigarettes and may be hazardousSecond-hand waterpipe smoke had significant levels of aromatic hydrocarbons, CO, PM2.5 and trace metalsMeasurements taken outdoors before and after the visit for comparison
Kassem et al212014USA24 homes were visited 3 times during a 7-day periodObservationalLevels of indoor air and surface nicotine, child uptake of nicotine, the carcinogen NNK, and the toxicant acrolein by measuring corresponding metabolites cotinine, NNAL and NNAL-glucuronides and 3-HPMAChildren living in homes of hookah smokers are exposed to nicotine, the carcinogen NNK and the toxicant acrolein, which pose a threat to long-term healthCompared with homes of non-smokers, children living in homes of daily or weekly/monthly hookah smokers had significantly elevated levels of cotinine and NNAL, with children of daily smokers also having significantly elevated 3-HPMA2 air samples were collected with passive diffusion monitor badges in the living room and child's bedroom. A blank non-analysed badge was placed in a third room
Markowicz et al182014SwedenFilters from 10 replicate sessions of waterpipe smokingObservationalMicrobial compounds in waterpipe smokeWaterpipe smoke creates a bioaerosol similarly to cigarette smokeIn a 1–2 h session, second-hand smoke from waterpipes produced a concentration of 2.8 pmol/m3 of LPS. Ergosterol was not detected. This is comparable to 22.2 pmol/m3 of LPS and 87.5 ng/m3 of ergosterol from smoking 5 cigarettesNA
Tamim et al222003Lebanon625 students from 5 different private schoolsObservationalInformation on demographic, in-home smoking, and students’ respiratory tract illnesses (cough, wheezing, runny nose, or nasal congestion)Children exposed to second-hand waterpipe smoke may develop respiratory problems22.6% (12/53) had wheezing or nasal congestion, 11.3% (6/53) had just wheezing, and 15.1% (8/53) had just nasal congestionNA
Zaidi et al172011Pakistan39 indoor venues (13 shisha smoking, 13 cigarette smoking, and 13 non-smoking)ObservationalMean concentration of PM2.5Air quality at shisha smoking venues had hazardous air qualityShisha smoking venues had an average PM2.5 of 1745 μg/m3Venues with other sources of indoor air pollution and non-air-conditioned venues exposed to outdoor pollution were excluded. Samples were obtained before entering the venues to calibrate the device
Zeidan et al232014Lebanon147 people surveyedObservationalQuestionnaires on sociodemographic characteristics, respiratory symptoms and exposure to second-hand smoke. Exhaled CO levelsSecond-hand waterpipe smoke may cause respiratory symptoms in non-smokersOf the 147 surveyed, 48 were exposed only to second-hand waterpipe smoke. 58% reported a chronic coughMeasurements of expired-air CO were calibrated with local environmental CO concentration
Zhang et al162013CanadaIndoor (n=12) and outdoor (n=5) air quality was assessed in Toronto, Canada waterpipe cafesObservationalAir nicotine, fine PM less than 2.5 μm in diameter, and ambient COAir quality of waterpipe cafés is a health hazard. Waterpipe smoking should be eliminated from indoor and outdoor hospitality venuesIndoor values were 1419 µg/m3 for PM2.5, 17.7 ppm for ambient CO, and 3.3 µg/m3 for air nicotine. Outdoor values were 80.5 µg/m3 for PM2.5, 0.5 ppm for ambient CO, and 0.6 µg/m3 for air nicotineMeasurements taken as far as possible from kitchen areas and open windows to reduce contamination. Background readings obtained outdoors in areas without nearby smokers
  • 3-HPMA, 3-hydroxypropylmercapturic acid; CO, carbon monoxide; EPI, Environmental Performance Index; LPS, lipopolysaccharides; NA, not applicable; NNAL, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol; NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; PAH, polycyclic aromatic hydrocarbon; PM, particulate matter.