Levels Of Benzene Research Articles

Ameliyathanenin Hava Kalitesi: Cerrahi Duman-Tanımlayıcı Bir Çalışma

Objective: Electrosurgery is used in almost all surgeries. The entire surgical team working in these operating rooms is exposed to surgical smoke. In the literature, there is no study examining the direct effect of surgical smoke on operating room staff and involving the entire surgical team in sampling. This study aimed to examine the operating room air quality due to surgical smoke. Material and Methods: This descriptive study was conducted in August 2018 in the operating room of the department of general surgery of a university hospital. Air samples were taken from different parts of the operating room during surgery, and levels of volatile organic compounds in the breathing zone of the surgical team were measured. Results: Volatile organic compounds were not detected in the air samples taken during the surgery. The measured levels were well below the limits that could affect human health. Levels of some volatile organic compounds in the breathing zone of the surgical team were above the limit. Benzene levels in the breathing zone of the surgical resident, scrub nurse, circulating nurse and support staff were above the normal limit, and the chloroform level of the support staff was above the normal limit. Conclusion: Levels of some volatile organic compounds in the surgical smoke from the breathing zone of operating room health care professionals were above the normal limit. It is recommended to establish a protocol for protection from surgical smoke in operating rooms and to take the necessary measures.

Predicting conditional maximum contaminant level exceedance probabilities for drinking water after wildfires with Bayesian regularized network ensembles

The severity and frequency of wildfires have increased throughout the Pacific Northwest in recent decades, costing lives and destroying large amounts of valuable resources and assets. This trend is predicted to persist because of climate change and the associated increased fire risk caused by prolonged droughts in combination with changes in land cover and land use, including rapid increases in wildland urban interface areas. The threat of benzene and other contaminants in drinking water from water distribution systems after wildfires is a relatively recently discovered problem that gained attention because of the significant health hazards that high levels of benzene in drinking water pose for humans. Driving processes leading to post-fire benzene contamination in water distribution systems are largely unknown. Currently, no deterministic process models exist to predict the risk of exceeded benzene levels in water distribution systems after wildfires. To address the lack of predictive models, we developed and tested an approach based on neural network models to spatially predict the conditional probabilities of exceeding maximum contaminant levels for benzene after wildfires. The Bayesian regularized neural networks were trained using high-resolution data layers comprising topography, soil properties, landcover, vegetation, meteorological parameters, fuel load, and infrastructure data for two wildland urban interface areas in northern California. The generalized model ensemble encompassing data from both communities exhibits an accuracy of 83% to 88% in spatially predicting the post-fire exceedance of benzene levels, offering a planning tool for emergency response and future risk mitigation efforts.

The competing role of moisture in adsorption of gaseous benzene on microporous carbon

The effects of moisture on adsorption of gaseous benzene have been investigated using microporous activated carbon (AC). Here, the performance metrics of an AC bed are explored in terms of the interplay between benzene concentrations (1–20 Pa) and relative humidity (RH, 0–100%). At lower benzene levels (<10 Pa), the adsorption capacity of AC bed was affected sensitively by water vapor with the performance reduction by 27–65% at 100% RH (e.g., relative to 0% RH). In contrast, the negative effect of water on AC performance was not so evident at higher benzene levels (~20 Pa) with only less than 5.3% decrease in the adsorption capacity. A test on the combinatory effects of temperature (25, 40, and 60 °C) and humudity (0 and 100% RH) confirms the relative dominance of temperature over moisture conditions in lowering AC performance. The isotherm analysis of benzene indicates complex fitting results of microporous AC across varying RH levels. The kinetic analysis further demonstrates that the physical nature of benzene is best explained by the pseudo-first order fitting. The test of temperature-swing cycles between adsorption–desorption clarifies the slight decreases in the adsorption capacity (reduction of 11.9% at 0% RH and 3.4% at 50% RH) at lower RH levels, although there is a prominent reduction (35.5%) at the saturated RH. As a whole, the commercial AC product is verified as an excellent adsorbent for purifying the atmosphere from gaseous aromatic pollutants like benzene under dynamically varying environmental conditions (e.g., in the presence of competing component like water vapor at different temperature conditions).

The Relationship between Duration of Benzene Exposure with Liver Enzymes in Car Painting Workshop Workers

Introduction: Benzene is a carcinogenic compound that can be found in a car painting workshop in Surabaya. The source of benzene in the car painting workshop comes from thinners. Inhalation is the main route for benzene to enter the body. The duration of benzene exposure can affect the accumulation of benzene concentrations. If work safety is not considered, the benzene compound can cause the liver disease. Furthermore, SGOT and SGPT are basic parameters of liver function. The study aims to determine the relationship between the duration of benzene exposure with SGOT and SGPT levels in car painting workshop workers. Method: observational research with a cross-sectional approach was applied as the method of this study. The research was conducted in a car painting workshop in 2019 with 20 workers. The variables were the duration of benzene exposure (hours/day) and levels of SGOT and SGPT. Data analysis used the Fisher's Exact Test and Coefficient Contingency test. Results: Workers worked with a duration of benzene exposure ≤ 8 hours/day by 70% and &gt; 8 hours/day by 30%. The measurement results exceeded the normal limit with the value of SGOT of 15% and the SGPT of 30%. Furthermore, the Sstatistical test show p-values between the duration of benzene exposure and SGOT (0.202) and SGPT (0.303), body weight with SGOT (1.000) and SGPT (1.000), education with SGOT (0.199) and SGPT (0.182) and alcohol consumption with SGOT (1.000) and SGPT (1.000). Conclusion: There was no relationship between the duration of benzene exposure with SGOT and SGPT levels in car painting workshop workers in Surabaya with a p-value &gt;0.05.Keywords: car painting workers, duration of benzene exposure, SGOT, SGPT

Estimating Exposure Intensity Based on Odor.

The odor detection threshold for a chemical typically varies widely across population members, and the values can be described by a lognormal distribution. Assuming that the parameters of a chemical's odor detection threshold distribution can be estimated, a method is presented to retrospectively estimate exposure intensity based on detecting the chemical's odor. The context is a single exposure period involving a single air contaminant. In brief, where k out of n identically exposed persons detect the chemical's odor, the best estimate of the chemical's concentration in air corresponds to the k ÷ n fractile of the odor detection threshold distribution. Where n is small and/or k ÷ n is close to zero or one, exact 100×(1-α)% confidence bounds for the fractile estimate can be computed without using the normal distribution assumption. In addition, statistical uncertainty in the parameter estimates of the chemical's odor detection threshold distribution can be considered via a parametric bootstrap procedure, such that an overall 100×(1-α)% confidence interval on the chemical's concentration in air is obtained. The method is illustrated for benzene. Analysis of the available benzene odor detection threshold literature provides best estimates of a population geometric mean equal to 37.8 ppm and geometric standard deviation equal to 1.92. In a hypothetical example in which two out of six workers detect the odor of benzene, the point estimate of the benzene exposure level is 28.5 ppm, and the approximate one-sided lower 95% confidence limit is 8.2 ppm. The present analysis also makes clear that odor does not provide an adequate warning of excessive levels of airborne benzene.

Childhood cancer and residential proximity to petrol stations: a nationwide registry-based case–control study in Switzerland and an updated meta-analysis

PurposeBenzene is a known carcinogen for adult leukemia. Exposure to benzene through parental occupation and the use of household products has been associated with childhood leukemia (CL). Ambient benzene has also been associated with CL and central nervous system (CNS) tumors. We aimed to investigate whether the higher ambient levels of benzene in proximity of petrol stations are associated with a greater risk of childhood cancers, leukemia, and CNS tumors.MethodsWe identified children diagnosed with cancer at age 0–15 years during 1985–2015 from the Swiss Childhood Cancer Registry and selected 10 age and sex-matched controls per case from national censuses. We calculated the distance from children’s home to the nearest petrol station using precise geocodes. We estimated odds ratios using conditional logistic regression adjusting for ambient levels of NO2, distance to highways, level of urbanization, and presence of a cantonal cancer registry. In addition, we ran a meta-analysis pooling current results for CL with those of previous studies.ResultsWe identified 6129 cases, of which 1880 were leukemias and 1290 CNS tumors. 24 cases lived within 50 m from a petrol station. The adjusted odds ratio of a cancer diagnosis for children thus exposed compared to unexposed children (> 500 m) was 1.29 (0.84–1.98) for all cancers combined, 1.08 (0.46–2.51) for leukemia, and 1.30 (0.51–3.35) for CNS tumors. During 2000–2015, when exposure assessment was more precise, the adjusted odds ratio for any cancer diagnosis was 1.77 (1.05–2.98). The summary relative risk estimate for CL in the meta-analysis including four studies was 2.01 (1.25–3.22).ConclusionsOur study provides weak support for an increased risk of childhood cancers among children living close to petrol stations. A meta-analysis including our study suggests an increased risk for CL.

Sunscreen use is not associated with increased blood concentrations of benzene among adults in the United States: Data from the National Health and Nutrition Examination Survey 2003-2006 and 2009-2018

To the Editor: Sunscreens are widely used photoprotective agents and regulated as over-the-counter drugs by the US Food and Drug Administration.1 Valisure, an independent pharmaceutical testing company, recently found elevated levels of benzene, a known human carcinogen of all exposure routes, in 78 batches of sunscreen and after-sun care products, with some containing nearly 3 times the US Food and Drug Administration concentration limit (2 parts per million).2,3 Benzene exposure is strongly linked to hematologic malignancies.

Screening-level assessment of cancer risk associated with ambient air exposure in Aamjiwnaang First Nation

BACKGROUND AND AIM: The manuscript reports findings from a screening-level assessment of cancer risk from outdoor air in and around Aamjiwnaang First Nation. Aamjiwnaang is situated in the Sarnia-Lambton area, which is known for its industrial and petrochemical industry. The area is also known for poor air quality, chemical spills and other environmental events. Residents are concerned about the health impacts of these exposures. Ambient air pollution can contribute to cardiovascular, respiratory diseases, and certain types of cancer. Some communities may be at higher risk to these negative health impacts due to their geographical proximity to pollution sources. METHODS: Outdoor air concentrations were collected from four monitoring stations in the Aamjiwnaang region for known carcinogens benzene and 1,3-butadiene. Air quality data from both current (2015-2016) and historical (1995-1996, 2005-2006) records were examined. Air concentrations were mapped with geographic information systems to assess spatial variations. Outdoor air concentrations were compiled and the Lifetime Excess Cancer Risks (LECR) associated with long-term exposure to known carcinogens were estimated. RESULTS:LECR results for both benzene and 1,3-butadiene were above one per million. The LECR for benzene was 6.4 per million when the Health Canada slope factor was applied and 12.0 when using the US EPA. For 1,3-butadiene the LECR estimate was 8.8 per million. While air quality has improved over time, in 2015-2016 benzene and 1,3 butadiene levels were higher in Aamjiwnaang than provincial averages. Furthermore, benzene levels were above the Ambient Air Quality Criteria target. CONCLUSIONS:We found that ambient air in and around Aamjiwnaang contains a higher annual average concentration of benzene than recommended and may be related to higher cancer risks. This work provides a better understanding of environmental exposures and potential associated cancer risks for residents in the Aamjiwnaang community. This study highlights the need for further air monitoring and a more detailed risk assessment. KEYWORDS: Cancer and cancer-precursors, Risk assessment, Air pollution

Proximity to petrochemical industry and risk of childhood asthma occurrence

BACKGROUND AND AIM: Petrochemical industrial complexes would emission s several pollutants that were associated with adverse effect in respiratory system. Aim of present study is using different surrogate indices of petrochemical exposure to evaluate the effect on childhood asthma. METHODS: We conducted a singleton birth cohort by using the 2000-2014 Taiwan Birth Certificate Database (TBCD), linked with Nation Health Insurance Research Database (NHIRD) for follow-up. The distance to the nearest petrochemical industrial parks (PIPs) and benzene exposure level were uses as surrogating petrochemical exposure indices. Exposure windows were divided into prenatal and postnatal periods. The Cox proportional hazard models were applied to evaluate the effects. RESULTS:In total, 227601 asthma cases were newly diagnosed until to 2016/12/31. Younger maternal age and greater proportions of male, preterm birth, low birth weight, delivery by Caesarean section, maternal gestational hypertension were observed for asthma children than non-asthma children. The results showed that compared with those living in the farthest, living close to PIPs (HR = 1.67, 95% CI: 1.65–1.70, for 10 km vs. ≥ 40 km) were observed to have an increased risk of asthma occurrence. Higher benzene exposure levels during prenatal or postnatal period having higher risks of asthma were also found. CONCLUSIONS:In present study, we found living near PIPs and exposure to higher level of benzene during prenatal or postnatal period would increase the risk of childhood asthma occurrence. KEYWORDS: Children's environmental health, Asthma, Chemical exposures

Air quality evaluation during COVID-19 in Southern Italy: the case study of Avellino city

The present study relies on the air quality evaluation during COVID-19 pandemic in Avellino, described in the last years and for several consecutive years, among the worst Italian cities in this context. The main purpose of this manuscript was to investigate the effects of quarantine and lockdown measures on air pollution. The concentrations of the main atmospheric pollutants (Carbon monoxide (CO), Ozone (O3), Fine Particulate (PM2.5 and PM10), Benzene (C6H6) and Nitrogen dioxide (NO2) were recorded during the period January–December 2020 using two stationary monitoring stations (AV1 and AV2) of the Regional Environmental Protection Agency (ARPAC). During the lockdown period (March 9-May 18, 2020), results indicated significant reductions only in the levels of CO, benzene and NO2, while for PM10 the limit of 50 μg m−3 was passed 8 times for AV1 and 13 times for AV2. The results showed the not predominant role of traffic on air quality in Avellino regards to PM levels and make it necessary a serious reflection about important and not extendable decisions to improve the air quality.

Assessment of Occupational Exposure to BTEX in a Petrochemical Plant via Urinary Biomarkers

This work presents the results of the first Serbian monitoring campaign performed to assess the occupational exposure of petrochemical industry workers to benzene (B), toluene (T), ethylbenzene (E), and xylene (X), known collectively as BTEX. The following urinary biomarkers were investigated: phenol, hippuric acid, o-Cresol, p-Cresol, and creatinine. BTEX compounds were collected in 2014 using Casella passive samplers. Multivariate statistical analysis was performed to put in evidence the correlation between the BTEX measured in air and the concentration of urinary biomarkers. While the results indicate an elevated presence of benzene in the air in the working environment studied that surpasses the national and European Occupational Exposure Limits (OEL), the levels of the remaining (TEX) parameters measured were below the OEL. The high relative standard deviations (RSD) for the concentrations of each BTEX compound (68–161 mg m−3) point toward an intensive occupational exposure to BTEX. This was confirmed by relevant urine biomarkers, particularly by the mean values of phenol, which were ten and fourteen times higher than the ones found in the control group (14–12 mg g−1 of creatinine). On average, workers are at a higher risk of developing cancer (6.1 × 10−3), with risk levels exceeding the US EPA limits. Benzene levels should therefore be maintained under tight controls and monitored via proper urinary biomarkers.

Survey of airborne organic compounds in residential communities near a natural gas compressor station: Response to community concern

IntroductionNatural gas compressor stations are located throughout the country and are used to maintain gas flow and ensure continuous distribution through the pipeline network. Compressor stations emit many air contaminants including volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs). While the serious health effects associated with the inhalation of elevated pollutant levels are clear, the relationship between proximity to natural gas compressor stations and residential health effects is not well understood. Community members living near a natural gas compressor station in Eastern Ohio expressed concerns regarding their air quality; therefore, the objective of this study was to assess exposure to airborne organics in residential air near the compressor station. MethodsOur team conducted a 24-hour air sampling campaign to assess outdoor and indoor air contaminant levels at 4 homes near the Williams Salem Compressor Station in Jefferson County, Ohio. Air quality was assessed using two techniques: 1) summa canisters to quantify VOC concentrations and 2) passive air samplers to evaluate a broader panel of VOCs and SVOCs. ResultsAmong the three homes situated < 2 km from the compressor station, indoor benzene levels were 2-17 times greater than the Ohio Environmental Protection Agency (EPA) indoor standard due to vapor intrusion. Multiple other VOCs, including ethylbenzene, 1,2,4-trimethylbenzene, 1,2 dichloroethane, 1,3 butadiene, chloroform, and naphthalene also exceeded state standards for indoor concentrations. Several SVOCs were also detected inside and outside participants’ homes, including benzene and naphthalene derivatives. ConclusionOur results validate the community members’ concerns and necessitate a more comprehensive epidemiological investigation into the exposures associated with natural gas compressor stations and methods to mitigate elevated exposures.Alarming levels of VOCS were detected inside of homes. Further research is needed to determine the source of VOC exposure and potential health effects.

Air pollution reducer using cluster corona electric field net

This research paper presents the air pollution reducer using cluster corona electric field net on principle of high frequency plasma process, high voltage adjusting technique and efficiency filter. The switching power supply circuit based on small inverter comprises of HF pulse generator using IC number 3526 for the high voltage adjustment at 1.8 kV, 2.9 kV, 3.5 kV, 3.9 kV and 4.1 kV under frequency adjustment at 10 kHz, 11 kHz, 12 kHz, 17 kHz and 22 kHz, respectively, and IC maker was used as a ground isolator and signal expanding for Power MOSFET#IRFP450 driving to control high voltage of high frequency transformer to generate 1.8 kV, 2.9 kV, 3.5 kV, 3.9 kV and 4.1 kV to electric field net cell (cell eliminate toxic gases) for produce ozone. The results are high frequency adjusting of high voltage at 1.8 kV equal to 10 kHz, 2.9 kV equal to 11 kHz, 3.5 kV equal to 12 kHz, 3.9 kV equal to 17 kHz and 4.1 kV equal to 22 kHz which the testing of ozone measuring will observation at high voltage equal 1.8 kV enables produce ozone 1.28 ppm, 2.9 kV enables produce ozone 1.56 ppm, 3.5 kV enables produce ozone 2.35 ppm, 3.9 kV enables produce ozone 2.61 ppm and 4.1 kV enables produce ozone 2.73 ppm. As the ozone content increases, the benzene and carbon monoxide levels decrease accordingly and can be used in the photocopying, printing, laminating and baking rooms covering an area of 200 square meters. Air pollution reducer can capture dust particles of PM2.5 size and has a dust extraction efficiency of 97.16 % by using a particulate meter which has passed the Electromagnetic Compatibility Standard Analysis (EMC Testing), the Power Consumption Analysis Test, and the Electric Leakage Safety Usage Analysis Test. are completed. Testing at the test room of electrical and electronic products testing center (PTEC), NSTDA, Thailand. Therefore, this research was funded activities to promote and support research of the Ministry of Higher Education, Science, Research and Innovation from the Department of Ramkhamhaeng University, fiscal year 2021 and can be developed into commercial innovations in the future.

The influence of benzene air pollution on leukemia incidence and mortality rates

Abstract The following study identifies areas where adverse conditions related to benzene pollution are concurrent with leukaemia incidence and mortality (C91–C95). Moreover, it determines the similarities between benzene and leukaemia levels, as well and rules defining their co-occurrence. The analysis covered the period of 2015–2017. Data were obtained from Dane.gov.pl (number of leukaemia cases), the Polish National Cancer Registry website (number of deaths), the Local Data Bank of the Central Statistical Office (population data) and the Chief Inspectorate of Environmental Protection and the Air Quality Portal (data on air quality). Based on the conducted analysis, it was concluded that the following poviat towns have an unfavourable epidemic situation related to leukaemia: Kielce (incidence), Rzeszów (incidence), Elbląg (mortality); meanwhile, high leukaemia incidence and mortality co-occurred with high average benzene concentration in 2015–2017 in the following poviat towns: Kielce, Rybnik, Płock and Rzeszów. It was found that leukaemias belonging to the three-character ICD-10 categories C94, C95 and C92 show the highest rate of co-occurrence with benzene concentration. In addition, two main rules for the co-occurrence of benzene pollution and leukaemia were identified. It was also noted that it is necessary to continue the research for a longer time period, especially in the poviat towns of Kielce and Rzeszów.

A sensing network involving citizens for high spatio-temporal resolution monitoring of fugitive emissions from a petroleum pre-treatment plant

In this study an innovative sensing network consisting of eight photoionization detectors, meteorological sensors, a video camera and a telephonic system able to systematize the population complaints was developed for the monitoring of odor emissions. The development of monitoring approaches with high temporal and spatial resolution and actively involving citizens, is strategic in areas where relevant and also short-term emissive events frequently occur and the conventional approaches fail due to the high variability of fugitive emissions. Moreover, even if unpleasant odors are not necessarily direct triggers of health effects, they could be associated with the release of other harmful compounds. Monitoring approaches also involving citizens are thus strategic tools because odors annoyance perceived by population may be a potential health risk warning. Therefore, the developed sensing network was set up in Val d'Agri (Basilicata, Italy) where a petroleum pre-treatment plant (COVA) rises in a rural and inhabited area. The data collected during the monitoring campaign from the 16th February to the 30th July 2017, showed Total Volatile Organic Compounds (TVOCs) concentrations decreasing moving away from the plant and up to five times higher than levels registered in the closest municipality (Viggiano). Moreover, recurrent short-term critical events characterized by concentration values far above the average of the period and with maximum values ranging from 0.92 to 1.89 ppm, were registered in correspondence with high levels of benzene (up to 23.9 μg/m3) and anemometric conditions able to transport pollutants from COVA to each receptor site. The spatial and temporal distribution of TVOC concentrations proved to be affected by the distance from COVA, wind direction and industrial activities verified using video reportage and citizen claims. Therefore, the developed approach has proven to be a useful tool to credit people's perception of odors and also to quantify citizen exposure to VOCs during short-term events.

NSF Response Case Study: Hazardous Materials Release at Intercontinental Terminal Company, Deer Park, Texas

ABSTRACT On March 17th, 2019 the Intercontinental Terminal Company (ITC) Deer Park, Texas river terminal and storage facility, comprised of 242 above ground storage tanks with a site capacity of 13.1 million barrels of hazardous products, experienced a tank fire. This incident would also become known as the “2nd 80s Fire” based on the identification of tanks impacted. The fire was contained to a single grouping of 15 tanks, with stored products including Naphtha, Toluene, Xylene, Benzene, Pyrolysis Gasoline, and Gasoline Blend stocks. Extended firefighting efforts resulted in volumes of water and firefighting foam that exceeded the capacity of the containment systems, resulting in the subsequent containment failure on March 22nd, which enabled the hazardous chemicals and mixture of various products to eventually reach the Houston Ship Channel. The surrounding industrial and residential communities experienced shelter-in-place orders due to the air quality concerns, and the vital waterway was shut down to commercial traffic. On-water benzene levels exceeded 20 parts per million (ppm) during the initial phases of the response near the facility while many areas within five miles exceeded the Occupational Safety Health Agency (OSHA) Permissible Exposure Limit (PEL) for benzene exposures. Benzene remained the primary chemical hazard to response crews seeking to contain, remove, and reopen the waterways for more than two weeks past the initial chemical release events. An interagency agreement was developed between the Environmental Protection Agency (EPA) and the U.S. Coast Guard (USCG) to assist in response activities, which included containing, collecting, recovering and disposing of the released materials from the shoreline and the surface water. The National Strike Force (NSF) deployed 52 personnel from each of the three Strike Teams, Public Information Assist Team (PIAT) and CG-Incident Management and Assistance Team (CG-IMAT). Due to the elevated presence of benzene, the NSF was the only USCG trained, experienced and qualified organic response resource prepared to respond to environmental threats with elevated concentrations of products that represented an inhalation hazard requiring respiratory protection devices. This paper demonstrates the significance of NSF's respiratory protection program, and how their capabilities can be used for both technical operations support, and also for site safety management, especially during complex spills or releases.

Biomarkers of Low-Level Environmental Exposure to Benzene and Oxidative DNA Damage in Primary School Children in Sardinia, Italy.

Background: The main anthropic sources of exposure to airborne benzene include vehicular traffic, cigarette smoke, and industrial emissions. Methods: To detect early genotoxic effects of environmental exposure to benzene, we monitored environmental, personal, and indoor airborne benzene in children living in an urban area and an area near a petrochemical plant. We also used urinary benzene and S-phenylmercapturic acid (S-PMA) as biomarkers of benzene exposure and urinary 8-hydroxydeoxyguanosine (8-OHdG) as a biomarker of early genotoxic effects. Results: Although always below the European Union limit of 5 μg/m3, airborne benzene levels were more elevated in the indoor, outdoor, and personal samples from the industrial surroundings compared to the urban area (p = 0.026, p = 0.005, and p = 0.001, respectively). Children living in the surroundings of the petrochemical plant had urinary benzene values significantly higher than those from the urban area in both the morning and evening samples (p = 0.01 and p = 0.02, respectively). Results of multiple regression modelling showed that age was a significant predictor of 8-OHdG excretion, independent of the sampling hour. Moreover, at the low exposure level experienced by the children participating in this study, neither personal or indoor airborne benzene level, nor personal monitoring data, affected 8-OHdG excretion. Conclusions: Our results suggest the importance of biological monitoring of low-level environmental exposure and its relation to risk of genotoxic effects among children.

Health Risk Assessment for the Exposure of Workers to BTEX at the Gasoline Stations

The study was conducted to assess the health risks of workers due to exposure to toxic gases including benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde and acetaldehyde at gasoline retail stations. In this study, data on the concentrations of the toxic gases were collected from the previously published studies in the qualified scientific journals. The health risk assessment was followed by the process of the United States Environment Protection Agency (U.S. EPA). The results show that the concentrations of benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde, and acetaldehyde were in the range of 12.40 - 357.5, 12.47 - 574.17, 2.05 - 156.5, 4.57 - 218, 2.36 - 77.04, 3.64 - 153.93 and 1.27- 27.83 µg/m3 , respectively. Life time cancer risk for gasoline station workers due to exposure to benzene, ethylbenzene, formaldehyde, and acetaldehyde was calculated in the ranges of 2.13x10-5 - 6.14x10-4 , 4.96x10-7 - 3.79x10-5 , 4.81x10-6 - 2.03x10-4 , and 7.99x10-7 - 1.75x10-5 , respectively. For non-carcinogenic compounds, the hazard index due to benzene, toluene, m, p-xylene, o-xylene were respectively in the range of 0.13 - 3.81, 7.97x10-4 - 0.04, 0.01 - 0.70 and 0.01 - 0.25. The findings revealed that there is high risk of cancer and non-cancer for the workers working at the gasolines stations if they are not taking good preventive measures. The calculation showed that the limit levels of benzene, toluene, ethylbenzene, xylene, formaldehyde and acetaldehyde should be reduced to 5.82x10-4 , 15.64, 4.13x10- 3 , 0.31, 7.57x10-4 and 1.59x10-3 mg/m3 , respectively to meet the safety levels for the workers at the gasoline stations. &#x0D; Keywords: benzene, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, life-time cancer risk, health

An optimized approach for estimating benzene in ambient air within an air quality monitoring network

Benzene is a carcinogenic air pollutant for which European legislation has set an annual limit and criteria for the number of fixed monitoring sites within air quality networks (AQMN). However, due to the limited number of fixed sites for benzene measurement, exposure data are lacking. Considering the relationship between benzene levels and other variables monitored within an AQMN, such as NO2, O3, temperature, solar radiation, and accumulated precipitation, this study proposes an approach for estimating benzene air concentrations from the related variables. Using the data of the aforementioned variables from 23 fixed stations during 2016-2017, the proposed approach was able to forecast benzene concentration for 2018 with high confidence, providing enriched data on benzene exposure and its trends. Moreover, the spatial distribution of the estimated versus the most representative benzene levels was quite similar. Finally, an artificial neural network identified the most representative fixed benzene monitoring sites within the AQMN.

Characterizing the Performance of a Compact BTEX GC-PID for Near-Real Time Analysis and Field Deployment.

In this study, we test the performance of a compact gas chromatograph with photoionization detector (GC-PID) and optimize the configuration to detect ambient (sub-ppb) levels of benzene, toluene, ethylbenzene, and xylene isomers (BTEX). The GC-PID system was designed to serve as a relatively inexpensive (~10 k USD) and field-deployable air toxic screening tool alternative to conventional benchtop GCs. The instrument uses ambient air as a carrier gas and consists of a Tenax-GR sorbent-based preconcentrator, a gas sample valve, two capillary columns, and a photoionization detector (PID) with a small footprint and low power requirement. The performance of the GC-PID has been evaluated in terms of system linearity and sensitivity in field conditions. The BTEX-GC system demonstrated the capacity to detect BTEX at levels as high as 500 ppb with a linear calibration range of 0–100 ppb. A detection limit lower than 1 ppb was found for all BTEX compounds with a sampling volume of 1 L. No significant drift in the instrument was observed. A time-varying calibration technique was established that requires minimal equipment for field operations and optimizes the sampling procedure for field measurements. With an analysis time of less than 15 min, the compact GC-PID is ideal for field deployment of background and polluted atmospheres for near-real time measurements of BTEX. The results highlight the application of the compact and easily deployable GC-PID for community monitoring and screening of air toxics.