The effects of ventilation and building characteristics on indoor air quality in waterpipe cafés

Ranking the environmental factors of indoor air quality of metropolitan independent coffee shops by Random Forests model

Independent coffee shops are the alternative workplaces for people working remotely from traditional offices but are not concerned about their indoor air quality (IAQ). This study aimed to rank the environmental factors in affecting the IAQ by Random Forests (RFs) models. The indoor environments and human activities of participated independent coffee shops were observed and recorded for 3 consecutive days including weekdays and weekend during the business hours. The multi-sized particulate matter (PM), particle-bound polycyclic aromatic hydrocarbons (p-PAHs), total volatile organic compounds (TVOCs), CO, CO₂, temperature and relative humidity were monitored. RFs models ranked the environmental factors. More than 20% of the 15-min average concentrations of PM₁₀, PM_2.5, and CO₂ exceeded the World Health Organization guidelines. Occupant density affected TVOCs, p-PAHs and CO₂ concentrations directly. Tobacco smoking dominated PM₁₀, PM_2.5, TVOCs and p-PAHs concentrations mostly. CO concentration was affected by roasting bean first and tobacco smoking secondly. The non-linear relationships between temperature and these pollutants illustrated the relative low concentrations happened at temperature between 22 and 24 °C. Tobacco smoking, roasting beans and occupant density are the observable activities to alert the IAQ change. Decreasing CO₂ and optimizing the room temperature could also be the surrogate parameters to assure the IAQ.

BTEX levels in rural households: Heating system, building characteristic impacts and lifetime excess cancer risk assessment

BTEX (benzene, toluene, ethylbenzene, and xylene) are a group of toxic organic compounds that exposure to them can cause adverse short and long terms health effects. We measured the levels of BTEX in the indoor and outdoor air of rural areas in Ardebil, Iran. We further assessed their health risks and determinants parameters. BTEX were sampled by drawing air through activated charcoal tubes, using low flow SKC pumps. Samples were extracted by adding carbon disulfide and analyzed by subjecting the aromatic fraction to GC-FID. The results indicated that the concentrations of BTEX in the indoor air were significantly higher than those of outdoor (p-value<0.05). The mean indoor concentrations of benzene, toluene, ethylbenzene, and xylene were 41.69 ± 30.70, 96.73 ± 60.75, 38.73 ± 33.59, and 59.42 ± 35.99 μg m^-3, while the mean outdoor concentrations of them were 8.94 ± 7.32, 36.93 ± 21.82, 7.66 ± 5.63, and 18.14 ± 10.25 μg m^-3, respectively. The concentrations of BTEX in indoor and outdoor of the rural areas that used kerosene fuel for heating systems were significantly higher than those used natural gas. The results indicated that the tobacco smoke is a notable temporary source of indoor BTEX. The mean inhalation lifetime cancer risk (LTCR) value of benzene for residents of rural houses with the natural gas and kerosene heating systems were 28.6 × 10^-6 and 97.2 × 10^-6, while for ethylbenzene these figures stood out at 29.1 × 10^-6 and 95.8 × 10^-6, respectively. LTCR value for residents who used kerosene fuel for heating was higher than the World Health Organization (WHO) recommended limit.

Latent class analysis of initial nicotine dependence among adult waterpipe smokers

Waterpipe (WP) tobacco smoking increases the risk of smoking-related health problems. In this study, we sought to identify the unobserved class memberships of WP-associated initial nicotine dependence (ND) symptoms and assess the predictors of each latent class. This cross-sectional study was conducted among a convenience sample of 900 current (past 30-day) WP smokers who were recruited from 94 WP-serving venues surrounding Tehran and Ardebil metropolitans in Iran. All participants completed a self-administrated questionnaire. We performed latent class analysis using PROC LCA in SAS to identify class memberships of initial ND symptoms using 10-item Hooked on Nicotine Checklist. Five latent classes were identified as non-dependent (25.4 %), low dependent (7.1 %), low-moderate dependent (19.6 %), moderate dependent (15.6 %), and high dependent (32.2 %). Using flavored WP tobacco significantly increased the odds of belonging to low-moderate dependent class [adjusted OR (aOR) = 1.89; 95 % confidence interval (CI): 1.07-3.34] compared to non-dependent class. Also, having academic education decreased the odds of belonging to low-moderate dependent (aOR = 0.43; 95 %CI: 0.26-0.67) and moderate dependent (aOR = 0.39; 95 %CI: 0.23-0.67) class in comparison to non-dependent class. Also, WP smoking initiation at an older age was associated with belonging to high dependent (OR = 2.05; 95 %CI: 1.39-3.03) class compared to non-dependent. This study revealed that nearly half of WP smokers fell under moderate and high-dependent classes. Our findings showed that some items of HONC had more role in the clustering of participants based on ND symptoms. The WP-specific cessation programs and targeted clinical trials should consider the diversity of ND levels among smokers to achieve successful quit rates among these smokers. Additionally, limiting flavors would be a strong strategy to limit the rate of ND, especially among young people who are eager to smoke flavored WP tobacco.

Bacteria bioaerosol in the indoor air of educational microenvironments: Measuring exposures and assessing health effects

Exposure to bioaerosols has been identified to be linked the incidence of various health effects, i.e., infectious diseases, acute toxic effects, allergies, and cancer. The aim of this study was to determine the bacterial bioaerosols in the indoor air of the educational environments of Ardabil universities and to evaluate the exposure and to determine its health risk. In this cross-sectional study, different sections of the educational environments of Ardabil universities were studied. For differential diagnosis of bacteria, methods such as gram staining and biochemical detection methods including DNAse, catalase, oxidase, coagulase, bile esculin hydrolysis test, urease, citrate test, antibiotic resistance to novobiocin and Bacitracin, optochin, glucose uptake, and other differential tests were used. For sampling, a single-stage Anderson sampler was used at a flow rate of 28.3 l at a duration of 10 min per minute. The results showed that, in medical school of Ardabil University of Medical Sciences, the average concentration of bacteria in the outdoor air of school, halls, classes and rooms of professors and staff were 18, 88.4, 76.6, and 77.4 CFU/m³, respectively, and, in Ardabil Islamic Azad University, the average bacterial concentration was 103, 97, 124, and 132 CFU/m³ in the outdoor air of the schools, halls, classrooms, and rooms of professors and staff, respectively. The predominant bacterial species in indoor air are S. aureus, S. epidermidis, Actinomycetes, and Bacillus, respectively. As results indicated, the concentration of bacterial bioaerosols in indoor air is within the standard levels, but due to frequency of bacterial species, occurrence of different in lung and intestinal diseases can be expected among faculty, staff and students in the long-term.

Characteristics of flavored and non-flavored waterpipe tobacco users: a real-world setting study

We aimed to compare sociodemographic characteristics, smoking patterns, beliefs and perceptions, nicotine dependence, and psychological indicators between flavored waterpipe (WP) tobacco (FWT) and non-flavored WP tobacco (non-FWT) smokers in Iran. A cross-sectional study was conducted in 94 WP-serving venues surrounding Tehran and Ardabil metropolitans in Iran. Convenience sampling was applied to select 900 current WP smokers [508 (56%) FWT-only and 392 (44%) non-FWT-only smokers] aged 18 years and older. Multivariable logistic regression was used to examine the independent characteristics of FWT and non-FWT smokers. Compared to non-FWT smokers, FWT smokers were younger (adjusted odds ratio [AOR]=0.88, 95% confidence interval [CI]: 0.87-0.90) and more likely to have ≥ 1 sibling who smoked WP (AOR=1.54, 95% CI: 1.06-2.24), share WP with others (AOR=2.52, 95% CI: 1.68-3.77), report current cigarette smoking (AOR=2.05, 95% CI: 1.23-3.42), and report confidence in quitting at any time (AOR=3.64, 95% CI: 2.45-5.39). FWT smokers were less likely to have seen (AOR=0.40, 95% CI: 0.27-0.60) or read (AOR=0.44, 95% CI: 0.24-0.80) warning messages on WP tobacco packages relative to non-FTW smokers. The most common self-reported reason for smoking WP was entertainment for both groups, followed by stress relief for non-FWT smokers and the escape from loneliness for FWT smokers. FWT-only smokers differ from non-FWT-only smokers in several aspects including being younger, having more positive beliefs and perceptions regarding WP use, and having higher cigarette smoking prevalence. These findings will help in developing more effective and targeted policies and cessation interventions for WP smokers according to flavor type they use, especially in the Middle East.

COVID-19 and beliefs about tobacco use: an online cross-sectional study in Iran

There is mixed evidence surrounding the relationship between tobacco use and COVID-19 infection/progression. The current study investigates beliefs and tobacco use behaviors and COVID-19 infection among a sample of smokers and never-smokers. Data were collected using an online survey distributed through Telegram, a cloud-based social media networking application in Iran from April 1 to May 31, 2020. The study participants included never-smokers (n = 511), current (past-month) waterpipe smokers (n = 89), current cigarette smokers (n = 158), and ex-smokers (n = 172). Multinomial logistic regression was used to compare tobacco use groups with never- smokers on beliefs, controlling for potential confounders. The study participants (n = 944) was mostly male (64%), had > high school education (76%), and lived in an urban area (91%), with mean ± SD age of 35.3 ± 10.8. Key findings of this study are that compared with never-smokers: (1) cigarette smokers were less likely to believe that smoking cigarette can lead to spreading COVID-19; (2) waterpipe smokers were more likely to believe that smoking waterpipe at home was a safe practice, that waterpipe protects against COVID-19, and smoking waterpipe may lead to a more rapid recovery from COVID-19; (3) both waterpipe and cigarette smokers believed that using e-cigarettes in public places was a safe practice during the COVID-19 pandemic; and (4) more than half of the ex-smokers stopped smoking due to COVID-19 and most of them planned to continue abstaining from smoking after the pandemic. Our findings underscore the need to raise awareness about the unsupported claims of a lower hazard of using tobacco products or possible protective effects against COVID-19 and to promote cessation programs.

Exposure to BTEX concentration and the related health risk assessment in printing and copying centers

This study was derived to investigation of BTEX (benzene, toluene, ethylbenzene, xylenes) concentrations in printing and copying centers (PCCs) in Ardabil city of Iran. Fifty-three PCCs were randomly selected from all the 136 number of PCCs and BTEX was sampled form their indoor air. The results showed that the concentration of BTEX in the indoor air PCCs is lower than the OELs (occupational exposure limit) in all cases. The obtained mean concentrations of benzene, toluene, ethylbenzene, and xylene were 93.6±63.2, 150.6±99.2, 34.3±16.8, and 29.5±15.2 μg/m³ respectively. Type of printer, number of printing and copying device, and type of ventilation system had significant influence on the BTEX concentration. The mean inhalation lifetime cancer risk (LTCR) value for benzene and ethylbenzene in the indoor air of the PCCs with LaserJet and inkjet printers was 44.4 × 10^-6 and 153.3 × 10^-6, and 23.4×10^-6 and 54.2× 10^-6, respectively, which were higher than EPA (Environmental Protection Agency) and World Health Organization (WHO) recommended limits. The hazard quotient (HQ) of benzene in the indoor air of the PCCs with inkjet printers was >1, which indicates that the non-carcinogenic risks associated with exposure to these compounds are considerable.