Distribution of volatile organic compounds in ambient air of Tehran

Low-level occupational exposure to BTEX and dyschromatopsia: a systematic review and meta-analysis

Objectives. The present study aimed to assess whether occupational exposure to low concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) is associated with color vision impairment. Methods. We queried PubMed, Scopus, Embase, Web of Science and ProQuest as the main databases, as well as gray literature such as Google Scholar. A random-effects model was used to assess relative risk. A funnel plot was created to assess publication bias. Meta-regression analysis was applied to identify variables that explain the between-study variation in the reported risk estimate. Results. An overall standardized mean difference of 0.529 (95% confidence interval [0.269, 0.788]; p < 0.0001) was obtained in the random-effects model, which corresponded to a medium-size effect. Duration and the levels of exposure to benzene, toluene and xylene were the significant predictors of the magnitude of the combined risk estimate. Chronic exposure to low levels of BTEX was associated with dyschromatopsia determined by the color confusion index. Conclusions. The impairments can occur even at exposures lower than the occupational exposure limits of BTEX. However, there are several flaws in the determination of workers' exposure, which did not allow to establish how low a level of these chemicals can cause color vision impairment.

Characterization and exposure assessment to urban air toxics across Middle Eastern and North African countries: a review

Middle East and North African (MENA) countries over the decades are experiencing rapid industrial and infrastructural growth combined with being the global hub of oil and gas industries. These economic transformations are associated with release of air pollutants including urban air toxics (UAT) through industrial, traffic, and constructional activities into ambient urban environments. UAT concentrations levels may exacerbate in most MENA countries considering high number of vehicular traffic populations and petrochemical industries which are one of the main sources of this pollutant. Therefore, the main objective of the study is to review major findings of UAT levels in urban areas across thirteen (13) MENA countries. The study characterizes various measured UAT, assesses their concentrations in ambient environment, and identifies their major sources of emissions by reviewing more than 100 relevant UAT papers across the selected MENA countries. It was found that benzene, heavy metals, formaldehyde, and dioxin-like compounds are the most reported UAT. The study concluded that road traffic, fuel stations, and petrochemical industries were identified as the main sources of ambient UAT levels. It was further reported that most of the studies were based on short-term ambient environment with limited studies in indoor environments. Therefore, it is highly recommended that future research should focus on innovative health impact assessment and epidemiological studies from exposure to UAT levels. Also embarking on sustainable mitigation approaches through urban greenery, eco-industrial estates infrastructural developments, and renewable energy shares will reduce UAT levels and improve human health.

Analysis of benzene air quality standards, monitoring methods and concentrations in indoor and outdoor environment

Benzene is a proven carcinogen. Its synergistic action with other pollutants can damage different components of the biosphere. Literature comparing the air quality standards of benzene, its monitoring methods and global concentrations are sparse. This study compiles the worldwide available air quality standards for benzene and highlights the importance of strict and uniform standards all over the world. It was found that out of the 193 United Nation member states, only 53 countries, including the European Union member states, have ambient air quality standard for benzene. Even where standards were available, in most cases, they were not protective of public health. An extensive literature review was conducted to compile the available monitoring and analysis methods for benzene, and found that the most preferred method, i.e, analyzing by Gas Chromatography and Mass spectroscopy is not cost effective and not suitable for real-time continuous monitoring. The study compared the concentrations of benzene in the indoor and outdoor air reported from different countries. Though the higher concentrations of benzene noticed in the survey were mostly from Asian countries, both in the case of indoor and outdoor air, the concentrations were not statistically different across the various continents. Based on the analyzed data, the average benzene level in the ambient air of Asian countries (371 μg/m3) was approximately 3.5 times higher than the indoor benzene levels (111 μg/m3). Similarly, the outdoor to the indoor ratio of benzene level in European and North American Countries were found to be 1.2 and 7.7, respectively. This compilation will help the policymakers to include/revise the standards for benzene in future air quality guideline amendments.

Temporal variations of atmospheric benzene and its health effects in Tehran megacity (2010-2013)

The main aims of the present research were (1) investigation of the temporal trends of atmospheric benzene concentrations in Tehran city during the period 2010 to 2013 and (2) assessment of carcinogenic and non-carcinogenic health risks of inhalation exposure to benzene. For the first objective, the data of ambient air benzene concentrations were derived from 15 air quality monitoring stations (AQMSs) in Tehran during the years 2010 to 2013 and they were temporally investigated after data cleaning and missing data imputation. The excess lifetime cancer risk (ELCR) and hazard quotient (HQ) were estimated to reveal the carcinogenic and non-carcinogenic health effects of exposure to ambient benzene. Our findings indicated that over 2010-2013, annual mean concentrations of benzene were in the range of 1.84 to 2.57 μg m^-3, and the highest annual mean concentration was observed in 2011 with a mean of 2.57 μg m^-3. The four-year average concentration of benzene during the period from 2010 to 2013 was 2.14 μg m^-3. Furthermore, the HQ for inhalation exposure to ambient benzene was lower than the acceptable risk level (HQ < 1) over the study time period which indicated that the non-carcinogenic effects are very unlikely to happen. In addition, health risk assessment for ELCR showed that the potential cancer risk for inhalation exposure to benzene was 1.67 × 10^-5 over the study period, which is significantly higher than the limits recommended by the U.S. EPA (1 × 10^-6). Our study clearly proves that the ambient benzene concentration in Tehran has substantially higher carcinogenic effects on the population. Appropriate sustainable control measures should be taken to reduce air benzene concentration and protect public health.

The safety of non-incineration waste disposal devices in four hospitals of Tehran

BACKGROUND

The safe management of hospital waste is a challenge in many developing countries.

OBJECTIVES

The aim of this study was to compare volatile organic compounds (VOCs) emissions and the microbial disinfectant safety in non-incineration waste disposal devices.

METHODS

VOC emissions and microbial infections were measured in four non-incineration waste disposal devices including: autoclave with and without a shredder, dry heat system, and hydroclave. Using NIOSH and US EPA-TO14 guidelines, the concentration and potential risk of VOCs in emitted gases from four devices were assessed. ProSpore2 biological indicators were used to assess the microbial analysis of waste residue.

RESULTS

There was a significant difference in the type and concentration of VOCs and microbial infection of residues in the four devices. Emissions from the autoclave with a shredder had the highest concentration of benzene, ethyl benzene, xylene, and BTEX, and emissions from the hydroclave had the highest concentration of toluene. The highest level of microbial infection was observed in the residues of the autoclave without a shredder.

CONCLUSIONS

There is an increased need for proper regulation and control of non-incinerator devices and for monitoring and proper handling of these devices in developing countries.

Oxidative DNA damage and influence of genetic polymorphisms among urban and rural schoolchildren exposed to benzene

Traffic related urban air pollution is a major environmental health problem in many large cities. Children living in urban areas are exposed to benzene and other toxic pollutants simultaneously on a regular basis. Assessment of benzene exposure and oxidative DNA damage in schoolchildren in Bangkok compared with the rural schoolchildren was studied through the use of biomarkers. Benzene levels in ambient air at the roadside adjacent to Bangkok schools was 3.95-fold greater than that of rural school areas. Personal exposure to benzene in Bangkok schoolchildren was 3.04-fold higher than that in the rural schoolchildren. Blood benzene, urinary benzene and urinary muconic acid (MA) levels were significantly higher in the Bangkok schoolchildren. A significantly higher level of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in leukocytes and in urine was found in Bangkok children than in the rural children. There was a significant correlation between individual benzene exposure level and blood benzene (rs=0.193, P<0.05), urinary benzene (rs=0.298, P<0.05), urinary MA (rs=0.348, P<0.01), and 8-OHdG in leukocyte (rs=0.130, P<0.05). In addition, a significant correlation between urinary MA and 8-OHdG in leukocytes (rs=0.241, P<0.05) was also found. Polymorphisms of various xenobiotic metabolizing genes responsible for susceptibility to benzene toxicity have been studied; however only the GSTM1 genotypes had a significant effect on urinary MA excretion. Our data indicates that children living in the areas of high traffic density are exposed to a higher level of benzene than those living in rural areas. Exposure to higher level of benzene in urban children may contribute to oxidative DNA damage, suggesting an increased health risk from traffic benzene emission.

Distribution of volatile organic compounds in ambient air of Kaohsiung, Taiwan

Automobile emissions have created a major hydrocarbon pollution problem in the ambient air of Taiwan. The aim of this study was to determine the volatile organic compounds (VOCs) in the ambient air of Kaohsiung, Taiwan. The spatial distribution, temporal variation, and correlations of VOCs at three study sites, selected based on traffic densities and distances from a freeway, were discussed. Sixty-four hydrocarbons were identified in the ambient air. Among all of the VOC species, acetone, aromatic and aliphatic compounds constituted the major constituents. Higher concentrations of VOCs existed further away from major arteries as compared to those found near the freeway. Therefore, the distance from the freeway may not be a sufficient index for reflecting actual air quality in the study area. Weather conditions, wind speed and direction did not affect the distribution of VOC concentrations in the three study sites. Other factors, such as the height and density of buildings, traffic conditions or commercial activities, might affect the distribution of VOCs.

Survey of air pollution in Cotonou, Benin--air monitoring and biomarkers

Exposure to genotoxic compounds present in ambient air has been studied in Cotonou, Benin, a city where two-stroke motorbikes are the major form of transportation and gasoline quality is poor. Personal monitoring and biomarkers were used to assess the exposure. Non-smoking taxi-moto drivers (city) and village residents were the study subjects. Benzene exposure was significantly higher in the city, as compared to the village (76.0+/-26.8 microg/m(3) versus 3.4+/-3.0, p=0.0004). Urinary excretion of benzene and S-phenylmercapturic acid (S-PMA) were also highest in subjects living in the city, whereas 1-hydroxypyrene was not different. The level of total polycyclic aromatic hydrocarbons (PAHs), associated with particles, ranged from 76.21 to 103.23 in Cotonou versus 1.55 ng/m(3) for the village. Determination of DNA damage in lymphocytes showed that subjects from the city had elevated number of lesions compared to subjects in the village in terms of bulky DNA adducts, 8-hydroxy-2'-deoxyguanosine and 5-methylcytosine, whereas DNA fragmentations analysed by alkaline gel electrophoresis was not different between the subjects. In conclusion, this study shows that air pollution is pronounced in Cotonou, Bénin and is associated with elevated levels of DNA damage in residents of the city compared to people living in a non-polluted rural village.

An investigation of the relationship between air emissions of volatile organic compounds and the incidence of cancer in Indiana counties

Cancer is a health endpoint influenced by a multitude of factors, including genetic history, individual behavior, and environmental insults. The ubiquity of toxicants in the environment has raised questions about the extent of their role in causing cancer in humans. More specifically, it is desirable to understand the cancer incidence due to airborne toxicants in anthropogenic pollution. One particular class of such pollutants is volatile organic compounds (VOCs). This paper reports an epidemiological investigation of the incidence of cancer in the 92 counties of Indiana. We evaluated the relationship between the amount of VOCs released in each county, as reported by the Toxic Release Inventory, and the county-by-county incidence of various types of cancer, especially those of less common organ systems not directly associated with the absorption or distribution of toxicants. Our evaluation considered chlorinated versus nonchlorinated emissions as well as stack versus fugitive emissions. We evaluated three models: linear, quadratic, and polynomial. Of these, the quadratic model appeared to be the best predictor (highest r2) for most endpoints for which there was a positive correlation. However, the linear model was the most sensitive (lowest P-value) for skin, melanoma, and endocrine-related cancers, including female genital system cancers. Our results indicate a relationship between emissions of VOCs and the incidence of some types of cancers. Most notable were strong correlations between VOC emissions and cancers of the brain, nervous system, endocrine system, and skin.

Gas chromatographic–mass spectroscopic determination of benzene in indoor air during the use of biomass fuels in cooking time

A gas chromatography-mass spectroscopic method in electron ionization (EI) mode with MS/MS ion preparation using helium at flow rate 1 ml min(-1) as carrier gas on DB-5 capillary column (30 m x 0.25 mm i.d. film thickness 0.25 microm) has been developed for the determination of benzene in indoor air. The detection limit for benzene was 0.002 microg ml(-1) with S/N: 4 (S: 66, N: 14). The benzene concentration for cooks during cooking time in indoor kitchen using dung fuel was 114.1 microg m(-3) while it was 6.6 microg m(-3) for open type kitchen. The benzene concentration was significantly higher (p < 0.01) in indoor kitchen with respect to open type kitchen using dung fuels. The wood fuel produces 36.5 microg m(-3) of benzene in indoor kitchen. The concentration of benzene in indoor kitchen using wood fuel was significantly (p < 0.01) lower in comparison to dung fuel. This method may be helpful for environmental analytical chemist dealing with GC-MS in confirmation and quantification of benzene in environmental samples with health risk exposure assessment.