Ana Rule
Johns Hopkins University, Environmental Health Science, Faculty Member
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School environment is a key exposure for school age children. Understanding the link between school community, school building, and indoor environment characteristics and student performance and he...
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Indoor air pollution is associated with adverse health effects; however, few studies exist studying indoor air pollution on the Navajo Nation in the southwest U.S., a community with high rates of respiratory disease. Indoor PM2.5... more
Indoor air pollution is associated with adverse health effects; however, few studies exist studying indoor air pollution on the Navajo Nation in the southwest U.S., a community with high rates of respiratory disease. Indoor PM2.5 concentration was evaluated in 26 homes on the Navajo Nation using real-time PM2.5 monitors. Household risk factors and daily activities were evaluated with three metrics of indoor PM2.5: time-weighted average (TWA), 90th percentile of concentration, and daily minutes exceeding 100 μg/m3. A questionnaire and recall sheet were used to record baseline household characteristics and daily activities. The median TWA, 90th percentile, and daily minutes exceeding 100 μg/m3 were 7.9 μg/m3, 14.0 μg/m3, and 17 min, respectively. TWAs tended to be higher in autumn and in houses that used fuel the previous day. Other characteristics associated with elevated PM exposure in all metrics included overcrowded houses, nonmobile houses, and houses with current smokers, pets, and longer cooking time. Some residents of the Navajo Nation have higher risk of exposure to indoor air pollution by Environmental Protection Agency (EPA) standards. Efforts to identify the causes and associations with adverse health effects are needed to ensure that exposure to risks and possible health impacts are mitigated.
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BackgroundAs more is known about the components of electronic cigarettes (e-cigarettes), it is important to characterize metal exposure from use. Nickel (Ni) and chromium (Cr) are frequent componen...
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Abstract Since April 2020, the U.S. Center for Disease Control (CDC) has asked for people to wear face masks in public to curb the spread of COVID-19. This shift has given rise to a mass movement of cloth mask making. Artists have leapt... more
Abstract Since April 2020, the U.S. Center for Disease Control (CDC) has asked for people to wear face masks in public to curb the spread of COVID-19. This shift has given rise to a mass movement of cloth mask making. Artists have leapt into action to produce masks for healthcare and frontline workers or as an alternative economy for lost income, while others customize masks to communicate identity, beliefs, or concerns. Mask making has also raised questions about the future of fashion with regards to health and sustainability. Through a series of conversations, experts from the arts, fashion, sustainability, and medical fields were invited to talk about the variety of issues, and questions this moment of mask making and wearing have produced. Since the beginning of the COVID-19 crisis, Dr. Ana María Rule has been helping the scientific community and the public understand the spread of particulates and the effectiveness of masks. Through scholarly publications, Rule has proposed ways of safely reusing limited personal protective equipment, and questioned the results of studies gauging the safety of textile facemasks. Rule agreed to speak in the Art of Masks series as a way to educate the textile interested community about the limits of fabric facemasks, and how best to protect themselves and others.
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Exposure to inorganic arsenic (iAS) through drinking water is well-associated with adverse cardiovascular outcomes, yet the mechanisms through which it induces these effects are not fully understood. Recent epidemiological findings... more
Exposure to inorganic arsenic (iAS) through drinking water is well-associated with adverse cardiovascular outcomes, yet the mechanisms through which it induces these effects are not fully understood. Recent epidemiological findings highlight an association between iAS exposure and altered left ventricular geometry in both the presence and absence of hypertension. We therefore tested the hypothesis that iAS exposure has a bimodal impact on cardiac-intrinsic and hemodynamic mechanisms that together induce pathological remodeling of the myocardium. Adult male and female mice were exposed to an environmentally relevant dose of 615 μg/L NaAsO 2 for eight weeks. Males (n=9-10 mice/group) exhibited increased systolic blood pressure (115.1±3.0 vs. 106.0±2.3 mmHg, p=0.0350) via tail cuff photoplethysmography, left ventricular wall thickening (0.98±0.01 vs. 0.88±0.01 mm, p<0.0001) via transthoracic echocardiography, increased heart weight to tibia length (8.56±0.21 vs. 7.15±0.24 mg/mm; n=2...
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The emergence of low-cost air quality sensors as viable tools for the monitoring of air quality at population and individual levels necessitates the evaluation of these instruments. The Flow air quality tracker, a product of Plume Labs,... more
The emergence of low-cost air quality sensors as viable tools for the monitoring of air quality at population and individual levels necessitates the evaluation of these instruments. The Flow air quality tracker, a product of Plume Labs, is one such sensor. To evaluate these sensors, we assessed 34 of them in a controlled laboratory setting by exposing them to PM10 and PM2.5 and compared the response with Plantower A003 measurements. The overall coefficient of determination (R2) of measured PM2.5 was 0.76 and of PM10 it was 0.73, but the Flows’ accuracy improved after each introduction of incense. Overall, these findings suggest that the Flow can be a useful air quality monitoring tool in air pollution areas with higher concentrations, when incorporated into other monitoring frameworks and when used in aggregate. The broader environmental implications of this work are that it is possible for individuals and groups to monitor their individual exposure to particulate matter pollution.
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Abstract: Nearly three billion people use solid fuels for cooking and heating, which leads to extremely high levels of household air pollution and is a major cause of morbidity and mortality. Many stove manufacturers have developed... more
Abstract: Nearly three billion people use solid fuels for cooking and heating, which leads to extremely high levels of household air pollution and is a major cause of morbidity and mortality. Many stove manufacturers have developed alternative cookstoves (ACSs) that are aimed at reducing emissions and fuel consumption. Here, we tested a traditional clay chulha cookstove (TCS) and five commercially available ACSs, including both natural draft (Greenway Smart Stove, Envirofit PCS-1) and forced draft stoves (BioLite HomeStove, Philips Woodstove HD4012, and Eco-Chulha XXL), in a test kitchen in a rural village of western India. Compared to the TCS, the ACSs produced significant reductions in particulate matter less than 2.5 µm (PM2.5) and CO concentrations (Envirofit: 22%/16%, Greenway:
Introduction: E-cigarettes have gained popularity among the youth with peak initiation risk at 14-15 years, and as a tool to combat tobacco addiction. Current scientific literature indicates that e...
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Hairdressers are exposed to volatile organic compounds (VOCs), many of which have been linked to acute and chronic health effects. Those hairdressers serving an ethnic clientele may potentially experience disproportionate exposures from... more
Hairdressers are exposed to volatile organic compounds (VOCs), many of which have been linked to acute and chronic health effects. Those hairdressers serving an ethnic clientele may potentially experience disproportionate exposures from frequent use of products containing VOCs or different VOC concentrations contained in products which are marketed to the specific needs of their clientele. However, no biomonitoring studies have investigated occupational exposures in this population. In the present pilot study, we sought to characterize concentrations and exposure determinants for 28 VOC biomarkers in post-shift urine samples among 23 hairdressers primarily serving an ethnic clientele. VOC biomarker concentrations among hairdressers of color were compared to concentrations among a comparison group of 17 office workers and a representative sample of women participating in the U.S. National Health and Nutrition Examination Survey. VOC biomarkers were detected in all hairdressers with higher concentrations observed among hairdressers serving a predominantly Black versus Latino clientele, and among hairdressers overall versus office workers and women in the U.S. general population. Median biomarker concentrations for acrolein,1,3-butadiene, and xylene in hairdressers were more than twice as high as those observed among office workers. Median concentrations for 1-bromopropane, acrolein and 1,3-butadiene were more than four times higher among all hairdressers compared to those reported among women in the U.S. general population. Select salon services (e.g., sister locs, flat ironing, permanent hair coloring, permanent waves or texturizing, Brazilian blowout or keratin treatment, etc.) were also associated with higher VOC biomarker concentrations among hairdressers. This pilot study represents the first biomonitoring analysis to characterize VOC exposures among women hairdressers of color and to provide evidence that this occupational population may experience elevated VOC exposures compared to women in the U.S. general population. Results from our study represent an important first step in elucidating occupational VOC exposures in this understudied occupational group. Larger studies among a racially and ethnically diverse cohort of hairdressers are warranted to confirm our findings and inform future exposure interventions in this understudied occupational population.
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Hairdressers are exposed to particulate matter (PM), a known air pollutant linked to adverse health effects. Still, studies on occupational PM exposures in hair salons are sparse. We characterized indoor air PM concentrations in three... more
Hairdressers are exposed to particulate matter (PM), a known air pollutant linked to adverse health effects. Still, studies on occupational PM exposures in hair salons are sparse. We characterized indoor air PM concentrations in three salons primarily serving an African/African American (AA) clientele, and three Dominican salons primarily serving a Latino clientele. We also assessed the performance of low-cost sensors (uRAD, Flow, AirVisual) by comparing them to high-end sensors (DustTrak) to conduct air monitoring in each salon over 3 days to quantify work shift concentrations of PM2.5 , respirable PM (RPM), and PM10 . We observed high spatial and temporal variability in 30-min time-weighted average (TWA) RPM concentrations (0.18-5518 μg/m3 ). Readings for the uRAD and AirVisual sensors were highly correlated with the DustTrak (R2 = 0.90-0.99). RPM 8-hour TWAs ranged from 18 to 383 µg/m3 for AA salons, and 9-2115 µg/m3 for Dominican salons. Upper 95th percentiles of daily RPM exposures ranged from 439 to 2669 µg/m3 . The overall range of 30-min TWA PM2.5 and PM10 concentrations was 0.13-5497 and 0.36-,541 μg/m3 , respectively. Findings suggest that hairdressers could be overexposed to RPM during an 8-hour shift. Additional comprehensive monitoring studies are warranted to further characterize temporal and spatial variability of PM exposures in this understudied occupational population.
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Hairdressers may be differentially exposed to phthalates through hair salon services provided and products used, yet no U.S. studies have investigated these exposures in this population. We characterized concentrations and exposure... more
Hairdressers may be differentially exposed to phthalates through hair salon services provided and products used, yet no U.S. studies have investigated these exposures in this population. We characterized concentrations and exposure determinants to nine phthalate metabolites in postshift urine samples among 23 hairdressers from three Black and three Dominican salons, as well as a comparison group of 17 female office workers from the Maryland/Washington D.C. metropolitan area. Overall, hairdressers had higher metabolite concentrations than office workers. The geometric mean (GM) for monoethyl phthalate (MEP) was 10 times higher in hairdressers (161.4 ng/mL) than office workers (15.3 ng/mL). Hairdressers providing select services and using certain products had higher GM MEP concentrations than those who did not: permanent waves/texturizing (200.2 vs 115.4 ng/mL), chemical straightening/relaxing (181.6 vs 92.1 ng/mL), bleaching (182.3 vs 71.6 ng/mL), permanent hair color (171.9 vs 83.2 ng/mL), and Brazilian blowout/keratin treatments (181.4 vs 134.6 ng/mL). Interestingly, hairdressers providing natural services had lower GM MEP concentrations than those who did not: twists (129.1 vs 215.8 ng/mL), sister locs/locs (86.0 vs 241.9 ng/mL), and afros (94.7 vs 203.9 ng/mL). Larger studies are warranted to confirm our findings and identify disparities in occupational phthalate exposures.
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O3 is a principal pollutant that coexists with PM in urban ambient air. Studies associate O3 and PM exposure with adverse health effects; however the mechanisms of action remain unclear. We implant...
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This presentation describes an occupational health needs assessment to identify the knowledge of occupational health hazards and barriers that impede the protection of Latino/a immigrants' health and safety in the workplace. In... more
This presentation describes an occupational health needs assessment to identify the knowledge of occupational health hazards and barriers that impede the protection of Latino/a immigrants' health and safety in the workplace. In addition to the influence of immigration status, we are particularly interested in differences according to gender and the types of labor. This work represents a partnership between university and workers' center leaders, with the intent of developing programs at a workers' center in Baltimore, MD. Baltimore, a new destination for Latino immigrants, lacks baseline data regarding Latinos' health and working conditions. There is also an invisibility of female immigrants and non-Mexican Latinos in the occupational health literature. Procedures include four focus groups (n=20) and 10 key informant interviews. Inclusion criteria are: 1) being at least 18 years old; 2) self-identifying as Latino/a immigrant; and 3) working in Baltimore for the past ...
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Secondhand smoke (SHS) exposure remains a major public health concern in the United States. Homes have become the primary source of SHS exposure, with elevated risks for residents of multiunit housing. Though this differential risk is... more
Secondhand smoke (SHS) exposure remains a major public health concern in the United States. Homes have become the primary source of SHS exposure, with elevated risks for residents of multiunit housing. Though this differential risk is well-documented, little is known about whether SHS exposure varies by floor height. The aim of this study was to examine whether SHS accumulates in higher floors of multiunit housing. Using validated passive nicotine sampling monitors, we sampled air nicotine concentrations on multiple floors of 21 high-rise (>15 floors) buildings in New York City. Within the buildings, measurements were collected in three locations: non-smoking individual apartments, hallways and stairwells. Measurements were collected in two winter and two summer waves to account for potential seasonality effects. We analyzed the percent of filters with detectable nicotine and quantified nicotine concentration (µg/m3). Higher floor levels were positively associated with both airbo...
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Aims: To quantify the concentration of toxic metals in seven commercially available brands of e-cigarette liquid and to compare the metals found in e-cigarette liquid to metals found in traditional...
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A25 AIR POLLUTION MECHANISMS: OXIDATIVE STRESS AND INFLAMMATION 16/8:15 AM-10:45 AM / Room 388-390 (Third Level), Morial Convention Center ... Airway Asthmatic Inflammation And Asthma Gene Dysregulation By Airborne Particulate Matter In... more
A25 AIR POLLUTION MECHANISMS: OXIDATIVE STRESS AND INFLAMMATION 16/8:15 AM-10:45 AM / Room 388-390 (Third Level), Morial Convention Center ... Airway Asthmatic Inflammation And Asthma Gene Dysregulation By Airborne Particulate Matter In Phoenix AZ And ...
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The purpose of this study is to characterize manganese oxidation states and speciation in airborne particulate matter (PM), and describe how these potentially important determinants of PM toxicity vary by location. Ambient PM samples were... more
The purpose of this study is to characterize manganese oxidation states and speciation in airborne particulate matter (PM), and describe how these potentially important determinants of PM toxicity vary by location. Ambient PM samples were collected from five counties across the US using a high volume sequential cyclone system that collects PM in dry bulk form segregated into “coarse” and “fine” size fractions. The fine fraction was analyzed for this study. Analyses included total Mn using ICP-MS, and characterization of oxidation states and speciation using X-ray Absorption Spectroscopy (XAS). XAS spectra of all samples and ten standard compounds of Mn were obtained at the National Synchrotron Light Source. XAS data was analyzed using Linear Combination Fitting (LCF). Results of the LCF analysis describe differences in composition between samples. Mn(II) acetate and Mn(II) oxide are present in all samples, while Mn(II) carbonate and Mn(IV) oxide are absent. To the best of our knowle...
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Vaping is the action of inhaling and exhaling aerosols from electronic cigarettes. The aerosols contain various amounts of toxic chemicals, including metals. The purpose of this study was to evaluate factors that can influence metal... more
Vaping is the action of inhaling and exhaling aerosols from electronic cigarettes. The aerosols contain various amounts of toxic chemicals, including metals. The purpose of this study was to evaluate factors that can influence metal levels, including flavor and nicotine content in the e-liquid, and puff duration. Aerosols were collected from both closed-system (cartridge-based) and open-system e-cigarettes using e-liquids with different flavors (fruit, tobacco, and menthol), nicotine content (0, 6, 24, and 59 mg/mL), and puff duration (1, 2, and 4 s). The concentrations of 14 metals in the collected aerosols were measured using inductively coupled plasma mass spectroscopy. Aerosol concentrations of As, Fe, and Mn varied significantly among fruit, tobacco, and menthol flavors in both closed-system and open-system devices. Concentrations of Al, Fe, Sn, and U were significantly higher in tobacco or menthol flavored aerosols compared to fruit flavors in closed-system devices. Aerosol W levels were significantly higher in tobacco flavored aerosols compared to fruit flavors in open-system devices. Concentrations of As, Fe, and Mn were higher in tobacco flavored aerosols compared to menthol flavors in both types of devices. The median Pb concentration decreased significantly from 15.8 to 0.88 μg/kg when nicotine content increased from 0 to 59 mg/mL, and median Ni concentration was 9.60 times higher in aerosols with nicotine of 59 mg/mL compared to 24 mg/mL (11.9 vs. 1.24 μg/kg) for closed-system devices. No significant differences were observed in aerosol metal concentrations for different puff durations. Aerosol metal concentrations varied widely between different flavors and nicotine content but not by puff duration. Flavor and nicotine content of the e-liquid could be potential factors in metal emissions. Some elements showed higher concentrations under certain conditions, highlighting the urgent need of developing strict product regulations, especially on e-liquid composition and nicotine content to inform e-cigarette users about metal exposure through vaping.
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Background: Indoor particulate matter is associated with worse outcomes in adults with COPD. It remains unknown whether reductions of indoor pollutants can improve respiratory morbidity. Methods: Eligible former smokers with... more
Background: Indoor particulate matter is associated with worse outcomes in adults with COPD. It remains unknown whether reductions of indoor pollutants can improve respiratory morbidity. Methods: Eligible former smokers with moderate-severe COPD received active or sham portable HEPA air cleaners and were followed for 6 months in this blinded randomized controlled trial. The primary outcome was 6-month change in Saint George’s Respiratory Questionnaire (SGRQ) . Secondary outcomes were exacerbation risk, respiratory symptoms, rescue medication use and 6MWD. Intention to treat analysis included all subjects and per protocol analysis included adherent participants (greater than 80% use of air cleaner). Findings: 116 participants were randomized of which 84.5% completed study. There was no statistically significant difference in improvement of total SGRQ, but the active filter group had greater reduction in SGRQ symptom subscale (s -7.7 [95% CI, -15.0 to -0.37]) and respiratory symptoms (BCSS, s -0.8 [95% CI, -1.5 to -0.1); and lower risk of moderate exacerbations (IRR 0.32 [95% CI, 0.12-0.91]) and rescue medication use (IRR 0.54 [95% CI, 0.33-0.86]) compared to sham group (all p<0.05). In per protocol analysis, there was statistically significant difference in primary outcome’s improvement (SGRQ) between the active filter vs. sham group (β-4.76 [95% CI, -9.2 to -0.34]) and in moderate exacerbation risk, BCSS and 6MWD. Participants spending more time indoors were more likely to have treatment benefit. Interpretation . This is the first environmental intervention study conducted among former smokers with COPD showing potential health benefits of portable HEPA air cleaners, particularly among those with greater adherence and spending a greater time in their home. Trial Registration: clinicaltrials.gov Identifier: #NCT02236858 Funding: The Clinical trial of air cleaners to improve indoor air quality and COPD health (CLEAN AIR) was supported by NIEHS R01ES022607 and T32HL007534. Air cleaners used in this trial were donated by Austin Air Cleaners, however the company did not have any input on study design, analysis or manuscript preparation. Declaration of Interest: NNH reports grants from NIH, grants from COPD Foundation, grants and personal fees from AstraZeneca, grants and personal fees from GSK, grants from Boehringer Ingelheim, personal fees from Mylan during the conduct of the study. NP reports a grant from NIH K award, during the conduct of the study. RP reports grants from NIH during the conduct of the study and personal fees from the Health Effects Institute outside the submitted work. GD reports grants from NIH, during the conduct of the study. RW reports grants from Sanofi-Aventis, grants and personal fees from Verona and Boehringer Ingelheim, non-financial support from Propeller Health, personal fees from AstraZeneca, Contrafect, Roche-Genentech, Merck, Mylan/Thervance, AbbVie, GSK, ChemRx, Kiniksa, Bristol Myers Squibb, Galderma, Kamada, Pulmonx, Kinevant, Puretech, Arrowhead, VaxArt, Polarean, and Galderma, outside the submitted work. MD reports grants from National Institutes of Health, Office of the Director, during the conduct of the study. AR reports grants from NIH, during the conduct of the study. MCM reports grants from NIH and EPA during the conduct of the study, personal fees from Aridis, GSK and Celgene outside the submitted work. KK reports grants from NIH, during the conduct of the study. HW, AF, KR, ME, PB have nothing to disclose. Ethical Approval: Participants provided written informed consent and the Johns Hopkins Medical Institutional Review Board approved the protocol (NA_00085617).
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Environmental exposures in schools, including microbial exposures, can lead to detrimental childhood health outcomes. We evaluated two sampling techniques – standard flocked swabs versus sterile electrostatic cloths – to quantify... more
Environmental exposures in schools, including microbial exposures, can lead to detrimental childhood health outcomes. We evaluated two sampling techniques – standard flocked swabs versus sterile electrostatic cloths – to quantify Staphylococcus bacterial burden from school surfaces. Electrostatic cloths demonstrated higher test sensitivity and yielded higher surface area-standardized colony forming units compared to swabs. Despite protocol standardization, consistently larger surface areas were sampled with electrostatic cloths. This suggest that electrostatic cloths were more effective and practical for fieldwork.
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Tobacco smoke exposure (TSE) harms children, who are often "captive smokers" in their own homes. Project Zero Exposure is a parent-oriented, theory-based intervention designed to reduce child TSE. This paper reports on findings... more
Tobacco smoke exposure (TSE) harms children, who are often "captive smokers" in their own homes. Project Zero Exposure is a parent-oriented, theory-based intervention designed to reduce child TSE. This paper reports on findings from the pilot study, which was conducted in Israel from 2013 to 2014. The intervention consisted of motivational interviews, child biomarker and home air quality feedback, a Web site, a video, and self-help materials. The primary outcome was child TSE as measured by hair nicotine. Secondary outcome measures were air nicotine and particulate matter, parental reports of TSE, parental smoking behavior, and TSE child protection. A single-group pre- and posttest design was used. Twenty-six of the 29 recruited families completed the study. The intervention was feasible to implement and acceptable to participants. Among the 17 children with reliable hair samples at baseline and follow-up, log hair nicotine dropped significantly after the intervention (= ....
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Electronic cigarettes (e-cigarettes) generate an aerosol by heating a solution (e-liquid) with a metallic coil. Whether metals are transferred from the coil to the aerosol is unknown. Our goal was to investigate the transfer of metals... more
Electronic cigarettes (e-cigarettes) generate an aerosol by heating a solution (e-liquid) with a metallic coil. Whether metals are transferred from the coil to the aerosol is unknown. Our goal was to investigate the transfer of metals from the heating coil to the e-liquid in the e-cigarette tank and the generated aerosol. We sampled 56 e-cigarette devices from daily e-cigarette users and obtained samples from the refilling dispenser, aerosol, and remaining e-liquid in the tank. Aerosol liquid was collected via deposition of aerosol droplets in a series of conical pipette tips. Metals were reported as mass fractions (μg/kg) in liquids and converted to mass concentrations (mg/m) for aerosols. Median metal concentrations (μg/kg) were higher in samples from the aerosol and tank vs. the dispenser (all<0.001): 16.3 and 31.2 vs. 10.9 for Al; 8.38 and 55.4 vs. <0.5 for Cr; 68.4 and 233 vs. 2.03 for Ni; 14.8 and 40.2 vs. 0.476 for Pb; and 515 and 426 vs. 13.1 for Zn. Mn, Fe, Cu, Sb, an...
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Most smoke-free legislation to reduce secondhand smoke (SHS) exposure exempts waterpipe (hookah) smoking venues. Few studies have examined SHS exposure in waterpipe venues and their employees. We surveyed 276 employees of 46 waterpipe... more
Most smoke-free legislation to reduce secondhand smoke (SHS) exposure exempts waterpipe (hookah) smoking venues. Few studies have examined SHS exposure in waterpipe venues and their employees. We surveyed 276 employees of 46 waterpipe tobacco venues in Istanbul, Moscow, and Cairo. We interviewed venue managers and employees and collected biological samples from employees to measure exhaled carbon monoxide (CO), hair nicotine, saliva cotinine, urine cotinine, urine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and urine 1-hydroxypyrene glucuronide (1-OHPG). We estimated adjusted geometric mean ratios (GMR) of each SHS biomarker by employee characteristics and indoor air SHS measures. There were 73 non-smoking employees and 203 current smokers of cigarettes or waterpipe. In non-smokers, the median (interquartile) range concentrations of SHS biomarkers were 1.1 (0.2, 40.9) µg/g creatinine urine cotinine, 5.5 (2, 15) ng/mL saliva cotinine, 0.95 (0.36, 5.02) ng/mg hair nicotine, 1.48 (0.98, 3.97) pg/mg creatinine urine NNAL, 0.54 (0.25, 0.97) pmol/mg creatinine urine 1-OHPG, and 1.67 (1.33, 2.33) ppm exhaled CO. An 8-hour increase in work hours was associated with higher urine cotinine (GMR: 1.68, 95% CI: 1.20, 2.37) and hair nicotine (GMR: 1.22, 95% CI: 1.05, 1.43). Lighting waterpipes was associated with higher saliva cotinine (GMR: 2.83, 95% CI: 1.05, 7.62). Non-smoking employees of waterpipe tobacco venues were exposed to high levels of SHS, including measurable levels of carcinogenic biomarkers (tobacco-specific nitrosamines and PAHs). Smoke-free regulation should be extended to waterpipe venues to protect non-smoking employees and patrons from the adverse health effects of SHS.