Simultaneous indoor and outdoor on-line hourly monitoring of atmospheric volatile organic compounds in an urban building. The role of inside and outside sources

Estimate of the C-Cl photoionization cross section and absolute photoionization cross sections of chlorinated organic compounds

Chlorinated organic compounds are prominently used for industrial production, but their vapors and emission byproducts can cause detrimental effects to human health and the environment. To accurately quantify organochlorine compounds, the absolute photoionization cross section of tetrachloroethylene, chlorobenzene, 1,2-dichlorobenzene, and chloroacetone are measured using multiplexed synchrotron photoionization mass spectrometry at the Advanced Light Source at Lawrence Berkeley National Laboratory. These measurements allow for the estimation of the C-Cl photoionization cross section, increasing quantification accuracy of chlorinated emissions for kinetic modeling and pollutant mitigation. CBS-QB3 calculations of adiabatic ionization energies and thermochemical appearance energies are also presented and agree well with the experimental results.

Exposure to BTEX is associated with cardiovascular disease, dyslipidemia and leukocytosis in national US population

BACKGROUND

Comprehensive research on the effects of individual benzene, toluene, ethylbenzene, and xylenes (BTEX) and their mixture measured in blood samples, on cardiovascular diseases (CVD) and related risk factors among the general population is limited.

OBJECTIVES

To investigate the effects of blood individual and mixed BTEX on total CVD and its subtypes, lipid profiles, and white blood cell (WBC) count.

METHODS

Survey-weighted multivariate logistic regression was used to examine the associations between blood individual and mixed BTEX with CVD and its subtypes in 17,007 participants from NHANES 1999-2018. The combined effect of BTEX mixture on CVD was estimated using weighted quantile sum modeling and quantile g-computation. Weighted multivariate linear regression assessed the effects of BTEX on lipid profiles and WBC, including its five-part differential count.

RESULTS

In comparison to the reference quartile of BTEX mixture, individuals in the highest quartile had a significantly increased adjusted odds ratio of CVD risk (1.64, 95 % CI: 1.23 to 2.19, P for trend = 0.008). Positive associations were observed for benzene, toluene, ethylbenzene, and m-/p-xylene, demonstrating a monotonically increasing exposure-response relationship. Mixed BTEX was associated with congestive heart failure (CHF), angina pectoris, and heart attack. Individual benzene, toluene, and ethylbenzene were associated with CHF, while toluene, ethylbenzene, and all xylene isomers were linked to angina pectoris. Benzene, toluene, and o-xylene were associated with heart attack. Both mixed and individual BTEX showed positive associations with triglycerides, cholesterol, low-density lipoprotein, and WBC, including its five-part differential count, but a negative relationship with high-density lipoprotein. Subgroup analyses identified modifying effects of smoking, drinking, exercise, BMI, hypertension, and diabetes on the associations between specific toxicants and CVD risk.

CONCLUSIONS

Exposure to BTEX was associated with cardiovascular diseases and cardiovascular risk factors. These findings emphasize the importance of considering blood BTEX levels when assessing cardiovascular health risks.

A Compact Monitor for Ethylene and Other Plant-Produced Volatile Organic Compounds for NASA Space Missions

In this work, we discuss the development of a compact analytical instrument for monitoring ethylene in compact greenhouses utilized by NASA to grow fresh vegetables in space. Traditionally, ethylene measurements are conducted by GC-MS systems. However, in space, they are not applicable due to their bulky size, heavy weight, special carrier gas requirement and high maintenance. Our group developed a compact and robust battery-powered ethylene monitor based on the principles of analytical gas chromatography. The device utilizes purified ambient air as a carrier gas and a metal oxide sensor as a GC detector. Implementation of a CarboWax 20 M packed column from Restek together with a Tenax TA pre-concentrator allowed us to achieve a 20 ppb limit of detection for ethylene. Full automation of measurements and reporting of concentrations was accomplished via the implementation of a Raspberry Pi 4 computer and a 7″ 720P LED capacitive touchscreen utilized for data output. Based on a feasibility study, a fully automated, industrial-grade ethylene monitoring and removal system for greenhouses was developed.

Low-dose blood BTEX are associated with pulmonary function through changes in inflammatory markers among US adults: NHANES 2007-2012

The effects of blood benzene, toluene, ethylbenzene, and xylenes (BTEX) on lung function among general adults remain unknown. We enrolled 5519 adults with measured blood BTEX concentrations and lung function from the US National Health and Nutrition Examination Survey 2007-2012. Weighted linear models were fitted to assess the associations of BTEX with lung function and inflammation parameters (white blood cell five-part differential count and C-reactive protein). The mediating effect of inflammation between BTEX and lung function was also examined. Blood BTEX concentrations decreased yearly from 1999 and were extremely low from 2007 to 2012. Benzene and toluene exerted the greatest influence on lung function in terms of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), calculated FEV1:FVC ratio, peak expiratory flow rate (PEFR), and forced mid expiratory flow (FEF_25-75%). Both ethylbenzene and all xylene isomers had no effects on FVC but reduced FEV1, FEV1:FVC ratio, PEFR, and FEF_25-75%. Weighted quantile analyses demonstrated that BTEX mixture was associated with decreases in FVC, FEV1, FEV1:FVC ratio, PEFR, and FEF_25-75%, with benzene weighted most heavily for all lung function parameters. BTEX also increased the levels of inflammation indicated by white blood cell five-part differential count and C-reactive protein, and increased levels of inflammation also reduced lung function. From multiple mediation analysis, inflammation mediated the effects of benzene on FEV1 and PEFR, the effects of toluene on FEV1, and the effects of ethylbenzene on FEV1 and PEFR. Low-dose exposure to BTEX was associated with reduced pulmonary function both in large and small airways. Inflammation could be involved in this pathogenesis.

Identification of Indoor Air Quality Factors in Slovenian Schools: National Cross-Sectional Study

Poor indoor air quality (IAQ) in schools is associated with impacts on pupils’ health and learning performance. We aimed to identify the factors that affect IAQ in primary schools. The following objectives were set: (a) to develop a questionnaire to assess the prevalence of factors in primary schools, (b) to conduct content validity of the questionnaire, and (c) to assess the prevalence of factors that affect the IAQ in Slovenian primary schools. Based on the systematic literature review, we developed a new questionnaire to identify factors that affect the IAQ in primary schools and conducted its validation. The questionnaires were sent to all 454 Slovenian primary schools; the response rate was 78.19%. The results show that the most important outdoor factors were the school’s micro location and the distance from potential sources of pollution, particularly traffic. Among the indoor factors, we did not detect a pronounced dominating factor. Our study shows that the spatial location of schools is key to addressing the problem of IAQ in schools.

Formaldehyde, acrolein and other carbonyls in dwellings of university students. Levels and source characterization

Fifteen carbonyl compounds were investigated in the living rooms and bedrooms of 25 university student flats in the urban area of Ciudad Real (Central Southern Spain) in wintertime. Carbonyls were sampled using Radiello ® passive samplers refilled in the laboratory according to the method described in ISO 16000-3 Standard. The most abundant carbonyls in the living rooms and bedrooms were formaldehyde, acetone, acetaldehyde, hexaldehyde and butyraldehyde. The median concentration levels in the living rooms and bedrooms were: 28.6 and 34.2 μg m^-3 for formaldehyde, 18.3 and 23.1 μg m^-3 for acetone, 14.3 and 15.8 μg m^-3 for acetaldehyde, 11.4 and 14.1 μg m^-3 for hexaldehyde and 10.8 and 12.4 μg m^-3 for butyraldehyde. The median concentration of formaldehyde, benzaldehyde, valeraldehyde and hexaldehyde was significantly higher in the bedrooms than in the living rooms. Indoor concentrations were significantly higher than outdoor concentrations for all carbonyl measured, indicating that sources in the indoor environment are prevailing in all flats. Principal component analysis, multiple linear regressions and Spearman correlation coefficients were used to investigate the origin, the indoor pollutants determinants and to establish common sources between carbonyls. Eight components were extracted from the application of PCA to the indoor and outdoor measurements accounting for 97.7% of the total variance. Formaldehyde, acetone, acetaldehyde and acrolein presented different indoor sources. In the multiple linear regression analysis, higher formaldehyde concentrations were found in those living rooms with wood floor and smoking was positively associated to acetone, propionaldehyde, benzaldehyde and isovaleraldehyde. Formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde and benzaldehyde concentrations were compared with relevant international guidelines, being their concentrations below recommended values except acrolein, where all measured flats exceeded the reference levels; it would be important to focus on the characterization of emission sources of acrolein in indoor air in order to minimise the exposure and health risk.

Source characterization and health risks of BTEX in indoor/outdoor air during winters at a terai precinct of North India

BTEX are the consistently found air contaminants in indoor and outdoor environments. In order to investigate the exposure levels of BTEX, the indoor and outdoor air was analyzed during winter season at homes located at four selected sites of Gorakhpur, Uttar Pradesh, India, which comprised residential, roadside, industrial and agricultural areas. BTEX were sampled with a low-flow pump (SKC model 220). Samples were extracted with CS₂ and the aromatic fraction was subjected to GC-FID. Mean indoor concentration of BTEX was highest at the agricultural (70.9 µg m^-3) followed by industrial (30.0 µg m^-3), roadside (17.5 µg m^-3) and residential site (11.8 µg m^-3). At outdoor locations, the mean BTEX levels were highest at the roadside (22.0 µg m^-3) followed by industrial (18.7 µg m^-3), agricultural (11.0 µg m^-3) and residential site (9.1 µg m^-3). The I/O ratios were greater than 1 at all the sites except roadside site, where I/O ratios for toluene, ethylbenzene and xylene were less than unity. Poor correlation between indoor and outdoor levels at each site further indicated the dominance of indoor sources. Factor analysis followed by one-way analysis of variance depicts that the presence of BTEX compounds at all the sites indicate a mixture of vehicular and combustion activities. For benzene, the ILTCR values exceeded the safe levels, whereas ethylbenzene was nearby to the recommended level 1 × 10^-6. The HQ values were above unity for agricultural (indoors) and industrial (outdoors) as an exception to all the other sites which indicted the value below unity.

Indoor air quality indicators and toxicity potential at the hospitals' environment in Dhaka, Bangladesh

Indoor air quality (IAQ) is a leading apprehension currently especially in the perilous atmosphere, like hospitals. Clean and fresh air is very crucial for the patients and healthcare professionals in the hospitals. Therefore, we examined IAQ indicators (PM_1.0, PM_2.5, PM₁₀, NO₂, CO₂, and TVOC) at sixteen locations of three hospitals with an emphasis on seasonal variations, indoor/outdoor correlation, and concomitant toxicity potential (TP) of human exposure between October 2019 and January 2020. For the measurement of trace gases (NO₂, CO₂, and TVOC), Aeroqual 500 series (New Zealand) sampler was used; particulate matter (PM_1.0, PM_2.5, and PM₁₀) concentrations and relative humidity (RH) were measured using the IGERESS air quality monitoring device (WP6930S, China). The total average concentration of IAQ indicators were 104.1 ± 67.6 (PM_1.0), 137.4 ± 89.2 (PM_2.5), and 159.0 ± 103.3 (PM₁₀) μgm^-3; 0.11 ± 0.02 (NO₂), 1047.1 ± 234.2 (CO₂), and 176.5 ± 117.7 (TVOC) ppm. Significant variations of IAQ indicators were observed between different locations of the hospitals. Winter IAQ indicators were much higher than post-monsoon season. Indoor particulate matter (PM) levels were lower than outdoor, but gaseous pollutants were higher in indoor than outdoor except NO₂. Indoor TVOC was about two times higher than outdoor and also higher in post-monsoon than winter. A good positive correlation was observed between indoor and outdoor particulate matter during winter. A strong positive correlation was obtained between NO₂ and RH with PM in winter. Very high (> 10) indoor toxicity potential (TP) values of PM_2.5 and PM₁₀ were determined during winter. Extremely high TP values indicated potential severe health consequences of the healthcare professionals and patients in indoor hospitals' environment.

Liquid crystal display screens as a source for indoor volatile organic compounds

Liquid crystal displays (LCDs) have profoundly shaped the lifestyle of humans. However, despite extensive use, their impacts on indoor air quality are unknown. Here, we perform flow cell experiments on three different LCDs, including a new computer monitor, a used laptop, and a new television, to investigate whether their screens can emit air constituents. We found that more than 30 volatile organic compounds (VOCs) were emitted from LCD screens, with a total screen area-normalized emission rate of up to (8.25 ± 0.90) × 10⁹ molecules ⋅ s^-1 ⋅ cm^-2 In addition to VOCs, 10 liquid crystal monomers (LCMs), a commercial chemical widely used in LCDs, were also observed to be released from those LCD screens. The structural identification of VOCs is based on a "building block" hypothesis (i.e., the screen-emitted VOCs originate from the "building block chemicals" used in the manufacturing of liquid crystals), which are the key components of LCD screens. The identification of LCMs is based upon the detailed information of 362 currently produced LCMs. The emission rates of VOCs and LCMs increased by up to a factor of 9, with an increase of indoor air humidity from 23 to 58% due to water-organic interactions likely facilitating the diffusion rates of organics. These findings indicate that LCD screens are a potentially important source for indoor VOCs that has not been considered previously.

A Systematic Review of Air Quality Sensors, Guidelines, and Measurement Studies for Indoor Air Quality Management

The existence of indoor air pollutants—such as ozone, carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen dioxide, particulate matter, and total volatile organic compounds—is evidently a critical issue for human health. Over the past decade, various international agencies have continually refined and updated the quantitative air quality guidelines and standards in order to meet the requirements for indoor air quality management. This paper first provides a systematic review of the existing air quality guidelines and standards implemented by different agencies, which include the Ambient Air Quality Standards (NAAQS); the World Health Organization (WHO); the Occupational Safety and Health Administration (OSHA); the American Conference of Governmental Industrial Hygienists (ACGIH); the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE); the National Institute for Occupational Safety and Health (NIOSH); and the California ambient air quality standards (CAAQS). It then adds to this by providing a state-of-art review of the existing low-cost air quality sensor (LCAQS) technologies, and analyzes the corresponding specifications, such as the typical detection range, measurement tolerance or repeatability, data resolution, response time, supply current, and market price. Finally, it briefly reviews a sequence (array) of field measurement studies, which focuses on the technical measurement characteristics and their data analysis approaches.

Prenatal exposure to VOCs and NOx and lung function in preschoolers

BACKGROUND

Several studies have shown that exposure to air pollutants affects lung growth and development and can result in poor respiratory health in early life.

METHODS

We included a subsample of 772 Mexican preschoolers whose mothers participated in a Prenatal Omega-3 fatty acid Supplements, GRowth, And Development birth cohort study with the aim to evaluate the impact of prenatal exposure to volatile organic compounds and nitrogen oxides on lung function measured by oscillation tests. The preschoolers were followed until 5 years of age. Anthropometric measurements and forced oscillation tests were performed at 36, 48, and 60 months of age. Information on sociodemographic and health characteristics was obtained during follow up. Prenatal exposure to volatile organic compounds and nitrogen oxides was evaluated using a land use regression models and the association between them was tested using a lineal regression and longitudinal linear mixed effect models adjusting for potential confounders.

RESULTS

Overall, the mean (standard deviation) of the measurements of respiratory system resistance and respiratory system reactance at 6, 8, and 10 Hz during the follow-up period was 11.3 (2.4), 11.1 (2.4), 10.3 (2.2) and -5.2 (1.6), -4.8 (1.7), and -4.6 hPa s L^-1 (1.6), respectively. We found a significantly positive association between respiratory resistance (β_Rrs6  = 0.011; 95%CI: 0.001, 0.023) (P < .05) and prenatal exposure to nitrogen dioxide and a marginally negatively association between respiratory reactance (β_Xrs6  = -11.40 95%CI: -25.26, 1.17 and β_Xrs8  = -11.91 95%CI: -26.51, 1.43) (P = .07) and prenatal exposure to xylene.

CONCLUSION

Prenatal exposure to air pollutants was significantly associated with the alteration of lung function measured by oscillation tests in these preschool children.

Diurnal variation of BTEX at road traffic intersection points in Delhi, India: source, ozone formation potential, and health risk assessment

The present study was carried out to observe the variation of volatile organic compounds (VOCs) namely benzene, toluene, ethylbenzene, and xylene isomers (BTEX) at three different sites of Delhi, during 2016-2017. Four hourly sampling was carried out day and night separately. Results showed that BTEX concentration was highest in post-monsoon and lowest in monsoon season. Again, daily variation shows that benzene (47%) and toluene (35%) were more during night than day when it was 44% and 33% respectively. Mean concentration of BTEX was observed in following order: ethylbenzene ~ o-xylene < m,p-xylene < toluene < benzene, while overall seasonal variation was observed as follows: post-monsoon > summer > winter > monsoon. Possible emission sources of BTEX were also established through corresponding ratios of individual compounds. Xylene isomers together accounted highest ozone formation potential. The risk assessments of BTEX were carried out in terms of non-cancer (the hazard quotient, HQ) and cancer (the incremental lifetime cancer risk, ILCR) regarding the inhalation exposure only. It was observed that benzene and xylene isomers possessed higher HQs than ethylbenzene and toluene at all sites throughout the study. Again, benzene was found with higher mean ILCR (3.58 × 10^-5) than ethylbenzene (1.47 × 10^-5).

Surface reservoirs dominate dynamic gas-surface partitioning of many indoor air constituents

Human health is affected by indoor air quality. One distinctive aspect of the indoor environment is its very large surface area that acts as a poorly characterized sink and source of gas-phase chemicals. In this work, air-surface interactions of 19 common indoor air contaminants with diverse properties and sources were monitored in a house using fast-response, on-line mass spectrometric and spectroscopic methods. Enhanced-ventilation experiments demonstrate that most of the contaminants reside in the surface reservoirs and not, as expected, in the gas phase. They participate in rapid air-surface partitioning that is much faster than air exchange. Phase distribution calculations are consistent with the observations when assuming simultaneous equilibria between air and large weakly polar and polar absorptive surface reservoirs, with acid-base dissociation in the polar reservoir. Chemical exposure assessments must account for the finding that contaminants that are fully volatile under outdoor air conditions instead behave as semivolatile compounds indoors.

Multisensory Gas Chromatography for Field Analysis of Complex Gaseous Mixtures

A novel approach to analysis of complex gaseous mixtures is presented. The approach is based on the utilization of a compact gas chromatograph in combination with an array of highly integrated and selective metal oxide (MOX) sensors. Thanks to the implementation of a multisensory detector, the device collects multiple chromatograms in a single run. The sensors in the integrated MEMS platform are very distinct in their catalytic properties. Hence, the time separation by chromatographic column is complemented by catalytic separation by a multisensory detector. Furthermore, the device can perform the analysis in a broad range of concentrations, from ppb to hundreds of ppm. Low ppb and even sub-ppb levels of detection for some analytes were achieved. As a part of this effort, nanocomposite gas sensors were synthesized for selective detection of hydrogen sulfide, mercaptans, alcohols, ketones, and heavy hydrocarbons.

Exposure levels and health risk assessment of ambient BTX at urban and rural environments of a terai region of northern India

Benzene, toluene and xylene (BTX) belong to an important group of aromatic volatile organic compounds (VOCs) that are usually emitted from various sources. BTX play a vital role in the tropospheric chemistry as well as pose health hazard to human beings. Thus, an investigation of ambient benzene, toluene and xylene (BTX) was conducted at urban and rural sites of Gorakhpur for a span of one year in order to ascertain the contamination levels. The sampling of BTX was performed by using a low-flow SKC Model 220 sampling pump equipped with activated coconut shell charcoal tubes with a flow rate of 250 ml/min for 20-24 h. The analysis was in accordance with NIOSH method 1501. The efficiency of pump was checked weekly using regulated rotameters with an accuracy of ±1%. The samples were extracted with CS₂ with occasional agitation and analyzed by GC-FID. The total BTX concentration ranged from 3.4 μg m^-3 to 45.4 μg m^-3 with mean value 30.95 μg m^-3 and median 24.8 μg m^-3. The mean concentration of total BTX was maximum during winter (39.3 μg m^-3), followed by summer (28.4 μg m^-3) and monsoon season (25.1 μg m^-3). The mean concentration of BTX at urban site (11.8 μg m^-3) was higher than that at rural site (8.8 μg m^-3). At both the sites, T/B and X/B ratios were highest in monsoon and lowest in winters. Toluene against benzene plot shows R² value of 0.96 and 0.49 at urban and rural sites respectively. Higher R² value at urban site clearly indicates similar sources of emission for benzene and toluene. At both the sites, the estimated integrated lifetime cancer risk (ILTCR) for benzene exceeded the threshold value of 1E-06 whereas the individual hazard quotients (HQ) for BTX did not exceed unity at any of the sites.

Outdoor air 1,3-butadiene monitoring near a petrochemical industry (Tarragona region) and in several Catalan urban areas using active multi-sorbent bed tubes and analysis through TD-GC/MS

1,3-Butadiene is a carcinogenic compound that can be emitted to the atmosphere from several sources, such as the combustion of organic matter or traffic. However, petrochemical industry is one of the main origins of this compound. Several campaigns (2013-2017) were conducted in twelve Catalan urban areas to determine 1,3-butadiene concentrations in outdoor air, five of which were close to Tarragona petrochemical region. 1,3-Butadiene was dynamically sampled in multi-sorbent bed tubes (Carbotrap, Carbopack X and Carboxen 569) using portable pump equipment. The analysis was performed by automatic thermal desorption coupled with capillary gas chromatography/mass spectrometry detector. El Morell, Perafort and Puigdelfí, located near petrochemical facilities, were the most impacted locations, with average concentrations up to 15±33, 33±41 and 27±39μgm^-3, respectively. Maximum 24h concentrations of 125μgm^-3 were observed in Puigdelfí. However, 1,3-butadiene average and maximum concentrations in the Tarragona petrochemical region diminished significantly (p≤0.05) in a drastic way (40-80%) since the first monitoring program in 2013. On the other hand, average concentrations in the rest of studied Catalan urban areas generally presented average values below 1μgm^-3, ranging from 0.07-1.1μgm^-3. Spain does have neither a monitoring strategy nor standard regulations related to 1,3-butadiene. Taking into account that relevant values can be found in locations near petrochemical facilities, a regulation should be implemented as soon as possible, at least in this specific areas.

Assessment of indoor levels of volatile organic compounds and carbon dioxide in schools in Kuwait

Indoor air quality (IAQ) in schools is a matter of concern because children are most vulnerable and sensitive to pollutant exposure. Conservation of energy at the expense of ventilation in heating, ventilation, and air conditioning (HVAC) systems adversely affects IAQ. Extensive use of new materials in building, fitting, and refurbishing emit various pollutants such that the indoor environment creates its own discomfort and health risks. Various schools in Kuwait were selected to assess their IAQ. Comprehensive measurements of volatile organic compounds (VOCs) consisting of 72 organic compounds consisting of aliphatic (C₃-C₆), aromatic (C₆-C₉), halogenated (C₁-C₇), and oxygenated (C₂-C₉) functional groups in indoor air were made for the first time in schools in Kuwait. The concentrations of indoor air pollutants revealed hot spots (science preparation rooms, science laboratories, arts and crafts classes/paint rooms, and woodworking shops/decoration rooms where local sources contributed to the buildup of pollutants in each school. The most abundant VOC pollutant was chlorodifluoromethane (R22; ClF₂CH), which leaked from air conditioning (AC) systems due to improper operation and maintenance. The other copious VOCs were alcohols and acetone at different locations due to improper handling of the chemicals and their excessive uses as solvents. Indoor carbon dioxide (CO₂) levels were measured, and these levels reflected the performance of HVAC systems; a specific rate or lack of ventilation affected the IAQ. Recommendations are proposed to mitigate the buildup of indoor air pollutants at school sites.

IMPLICATIONS

Indoor air quality in elementary schools has been a subject of extreme importance due to susceptibility and sensibility of children to air pollutants. The schools were selected based on their surrounding environment especially downwind direction from the highly industrialized zone in Kuwait. Extensive sampling from different sites in four schools for comprehensive VOCs and CO₂ were completed for an extended period of over a year. Different hot spots were identified where leaked refrigerant and inadequate handling of laboratory solvents contributed to the high VOCs in the respective locations. CO₂ levels reflected HVAC performance and poor ventilation. A list of recommendations has been proposed to eradicate these high levels of air pollution.

Blood pressure in indoor and outdoor workers

INTRODUCTION

The aim of our study is to evaluate the changes in systolic and diastolic blood pressure in two occupational categories: outdoor workers (traffic policemen and environment technicians) and indoor workers.

MATERIALS AND METHODS

The study was conducted comparing the results obtained from three samples of male workers: 175 outdoor traffic policemen, 175 outdoor environment technicians and 175 indoor workers. The outdoor and indoor groups were made comparable by age, length of service, body mass index, alcohol consumption, smoking status.

RESULTS

The mean values of systolic and diastolic blood pressure were found higher in traffic policemen and technicians than in indoor workers, as well as higher values of systolic blood pressure in traffic policemen than in technicians.

CONCLUSIONS

The results suggest that outdoor working affects the blood pressure, contributing to an increased cardiovascular risk.

Statistical modeling of O3, NOx, CO, PM2.5, VOCs and noise levels in commercial complex and associated health risk assessment in an academic institution

Indoor Air Quality (IAQ) is considered to be of great concern due to its adverse impact on the human health nowadays. The presence of different air pollutants along with noise may aggravate the IAQ. The present study attempts to examine IAQ in terms of major criteria air pollutants (O₃, NOx=NO+NO₂, CO and PM_2.5) along with total volatile organic compound (TVOC), individual VOC and noise pollution in indoor and outdoor environment of a Commercial Shopping Complex (CSC) in Delhi. Real time measurements have been carried out for O₃, NOx, CO, PM_2.5, TVOC and noise while thirteen individual VOCs have been estimated using NIOSH method was performed using Gas Chromatograph. The study also aimed to find out the relationship among VOCs, source estimation using Principal Component Analysis. The observed results for the targeted pollutants were also compared with international and national recommended permissible values. The mean values of O₃, NOx, CO, PM_2.5 and TVOC are found to be 17.6/(15.0) ppb, 15.8/(14.1) ppb, 8.4/(1.9) ppm, 125.4/(74.6) μg/m³ and 412.5/(226.5) μg/m³ for indoor/(outdoor), respectively. Among the individual VOC, toluene was the most abundant followed by xylene-isomers and benzene. The noise pollution level in Indoor/outdoor were found to be 51.5/46.4dB which is below the guideline value (65dB) provided by the WHO. Most of the pollutants were found to have indoor sources. The different kinds of pollutants and noise may have synergistic effect and aggravate the health of the people working and visiting the CSC.

The MERMAID study: indoor and outdoor average pollutant concentrations in 10 low-energy school buildings in France

Indoor air quality was characterized in 10 recently built energy-efficient French schools during two periods of 4.5 days. Carbon dioxide time-resolved measurements during occupancy clearly highlight the key role of the ventilation rate (scheduled or occupancy indexed), especially in this type of building, which was tightly sealed and equipped with a dual-flow ventilation system to provide air refreshment. Volatile organic compounds (VOCs) and inorganic gases (ozone and NO2 ) were measured indoors and outdoors by passive techniques during the occupied and the unoccupied periods. Over 150 VOC species were identified. Among them, 27 species were selected for quantification, based on their occurrence. High concentrations were found for acetone, 2-butanone, formaldehyde, toluene, and hexaldehyde. However, these concentrations are lower than those previously observed in conventional school buildings. The indoor/outdoor and unoccupied/occupied ratios are informative regarding emission sources. Except for benzene, ozone, and NO2 , all the pollutants in these buildings have an indoor source. Occupancy is associated with increased levels of acetone, 2-butanone, pentanal, butyl acetate, and alkanes.

Atmospheric carbon tetrachloride in rural background and industry surrounded urban areas in Northern Iberian Peninsula: Mixing ratios, trends, and potential sources

Latest investigations on atmospheric carbon tetrachloride (CTC) are focused on its ozone depleting potential, adverse effects on the human health, and radiative efficiency and Global Warming Potential as a greenhouse gas. CTC mixing ratios have been thoroughly studied since its restriction under the Montreal Protocol, mostly in remote areas with the aim of reporting long-term trends after its banning. The observed decrease of the CTC background mixing ratio, however, was not as strong as expected. In order to explain this behavior CTC lifetime should be adjusted by estimating the relative significance of its sinks and by identifying ongoing potential sources. Looking for possible sources, CTC was measured with high-time resolution in two sites in Northern Spain, using auto-GC systems and specifically developed acquisition and processing methodologies. The first site, Bilbao, is an urban area influenced by the surrounding industry, where measurements were performed with GC-MSD for a one-year period (2007-2008). The second site, at Valderejo Natural Park (VNP), is a rural background area where measurements were carried out with GC-FID and covering CTC data a nonsuccessive five-year period (2003-2005, 2010-2011, and 2014-2015years). Median yearly CTC mixing ratios were slightly higher in the urban area (120pptv) than in VNP (80-100pptv). CTC was reported to be well mixed in the atmosphere and no sources were noticed to impact the rural site. The observed long-term trend in VNP was in agreement with the estimated global CTC emissions. In the urban site, apart from industrial and commercial CTC sources, chlorine-bleach products used as cleaning agents were reported as promotors of indoor sources.

Comparison of the impact of the Tobacco Heating System 2.2 and a cigarette on indoor air quality

The impact of the Tobacco Heating System 2.2 (THS 2.2) on indoor air quality was evaluated in an environmentally controlled room using ventilation conditions recommended for simulating "Office", "Residential" and "Hospitality" environments and was compared with smoking a lit-end cigarette (Marlboro Gold) under identical experimental conditions. The concentrations of eighteen indoor air constituents (respirable suspended particles (RSP) < 2.5 μm in diameter), ultraviolet particulate matter (UVPM), fluorescent particulate matter (FPM), solanesol, 3-ethenylpyridine, nicotine, 1,3-butadiene, acrylonitrile, benzene, isoprene, toluene, acetaldehyde, acrolein, crotonaldehyde, formaldehyde, carbon monoxide, nitrogen oxide, and combined oxides of nitrogen) were measured. In simulations evaluating THS 2.2, the concentrations of most studied analytes did not exceed the background concentrations determined when non-smoking panelists were present in the environmentally controlled room under equivalent conditions. Only acetaldehyde and nicotine concentrations were increased above background concentrations in the "Office" (3.65 and 1.10 μg/m(3)), "Residential" (5.09 and 1.81 μg/m(3)) and "Hospitality" (1.40 and 0.66 μg/m(3)) simulations, respectively. Smoking Marlboro Gold resulted in greater increases in the concentrations of acetaldehyde (58.8, 83.8 and 33.1 μg/m(3)) and nicotine (34.7, 29.1 and 34.6 μg/m(3)) as well as all other measured indoor air constituents in the "Office", "Residential" and "Hospitality" simulations, respectively.

A systematic review of evidence and implications of spatial and seasonal variations of volatile organic compounds (VOC) in indoor human environments

Many volatile organic compounds (VOC) are classified as known or possible human carcinogens, irritants, and toxicants, and VOC exposure has been associated with asthma and other respiratory symptoms/diseases. This review summarizes recent quantitative data regarding VOC in four categories of indoor environments (schools, housing, offices, and other indoor) and compares the types and concentration levels of individual VOC that were detected, measured, and reported according to season (cold and warm). The influence of outdoor air on concentrations of indoor VOC was also assessed as ratios of indoor versus outdoor. Papers published from 2000 onward were reviewed and 1383 potentially relevant studies were identified. From these, 177 were removed after duplication, 1176 were excluded for not meeting the review criteria, and 40 were included in this review. On average, higher mean concentrations of indoor VOC were found in housing environments, in offices, and in the cold season. Volatile organic compounds are commonly present in indoor air and specific compounds, and their concentrations vary among indoor environments and seasons, indicating corresponding differences in sources (indoors and outdoors). Actions and policies to reduce VOC exposures, such as improved product labeling and consumer education, are recommended.

Levels and sources of volatile organic compounds including carbonyls in indoor air of homes of Puertollano, the most industrialized city in central Iberian Peninsula. Estimation of health risk

Twenty nine organic air pollutants including carbonyl compounds, alkanes, aromatic hydrocarbons and terpenes were measured in the indoor environment of different houses together with the corresponding outdoor measurements in Puertollano, the most industrialized city in central Iberian Peninsula. VOCs were sampled during 8 weeks using Radiello(®) passive samplers, and a questionnaire on potential VOCs sources was filled out by the occupants. The results show that formaldehyde and hexanal was the most abundant VOCs measured in indoor air, with a median concentration of 55.5 and 46.4μgm(-3), respectively followed by butanal (29.1μgm(-3)), acetone (28.4μgm(-3)) and acetaldehyde (21.4μgm(-3)). After carbonyls, n-dodecane (13.1μgm(-3)) and terpenes (α-pinene, 13.4μgm(-3) and limonene, 13.4μgm(-3)) were the compounds with higher median concentrations. The indoor/outdoor (I/O) ratios demonstrated that sources in the indoor environment are prevailing for most of the investigated VOCs especially for limonene, α-pinene, hexanal, formaldehyde, pentanal, acetaldehyde, o-xylene, n-dodecane and acetone with I/O ratio >6. Multiple linear regressions were applied to investigate the indoor VOC determinants and Spearman correlation coefficients were used to establish common sources between VOCs. Finally, the lifetime cancer risk associated to formaldehyde, acetaldehyde and benzene exposure was estimated and they varied from 7.8×10(-5) to 4.1×10(-4) for formaldehyde, from 8.6×10(-6) to 3.5×10(-5) for acetaldehyde and from 2.0×10(-6) to 1.5×10(-5) for benzene. For formaldehyde, the attributed risk in most sampled homes was two orders of magnitude higher than the one (10(-6)) proposed as acceptable by risk management bodies.

Exhaled breath analysis in suspected cases of non-small-cell lung cancer: a cross-sectional study

Lung cancer is one of the most frequently diagnosed cancers worldwide and is still the leading cause of cancer-related deaths. There is a considerable interest in finding diagnostic methods in the disease's earliest stages. A complementary approach to imaging techniques could be provided by exhaled breath gas phase and exhaled breath condensate (EBC) analysis. The aim of this study was to quantify various biomarkers in the exhaled breath gas phase and EBC in suspected cases of non-small-cell lung cancer (NSCLC). The study involved 138 subjects with suspected lung cancer, 71 of whom had a subsequent diagnosis of NSCLC. The diagnostic power of a combination of hydrogen peroxide (H₂O₂)-EBC, and exhaled pentane, 2-methyl pentane, hexane, ethyl benzene, heptanal, trans-2-nonenal in distinguishing NSCLC and non-NSCLC subjects was poor-to-fair (area under the curve (AUC) = 0.68), similar to that of smoking history alone (expressed as pack-years, AUC = 0.70); a further improvement was observed when smoking history was combined with exhaled compounds (AUC = 0.80). The diagnostic power was increased in those patients with little or no past smoke exposure (AUC = 0.92) or where past smoke exposure was up to 30 pack-years (AUC = 0.85). Exhaled substances had a good accuracy in discriminating suspected cancerous cases only in those subjects with a modest smoking history (≤ 30 pack-years), but the inclusion of other exhaled biomarkers may increase the overall accuracy, regardless of tobacco smoke.

Making silicon solar cells in a green, low-hazardous, and inexpensive way

A facile, green, HF-free process for fabricating silicon solar cells safely at home or in school is presented.

A new agent for derivatizing carbonyl species used to investigate limonene ozonolysis

A new method for derivatizing carbonyl compounds is presented. The conversion of a series of dicarbonyls to oximes in aqueous solution and from gas-phase sampling was achieved using O-tert-butyl-hydroxylamine hydrochloride (TBOX). Some advantages of using this derivatization agent include: aqueous reactions, lower molecular weight oximes, and shortened oxime-formation reaction time. Additionally, the TBOX derivatization technique was used to investigate the carbonyl reaction products from limonene ozonolysis. With ozone (O3) as the limiting reagent, four carbonyl compounds were detected: 7-hydroxy-6-oxo-3-(prop-1-en-2-yl)heptanal; 3-Isopropenyl-6-oxoheptanal (IPOH), 3-acetyl-6-oxoheptanal (3A6O) and one carbonyl of unknown structure. Using cyclohexane as a hydroxyl (OH•) radical scavenger, the relative yields (peak area) of the unknown carbonyl, IPOH, and 3A6O were reduced indicating the influence secondary OH radicals have on limonene ozonolysis products. The relative yield of the hydroxy-dicarbonyl based on the chromatogram was unchanged suggesting it is only made by the limonene + O3 reaction. The detection of 3A6O using TBOX highlights the advantages of a smaller molecular weight derivatization agent for the detection of multi-carbonyl compounds. The use of TBOX derivatization if combined with other derivatization agents may address a recurring need to simply and accurately detect multi-functional oxygenated species in air.

Determination of volatile organic compounds and associated health risk assessment in residential homes and hostels within an academic institute, New Delhi

The purpose of this study was to investigate the concentrations of volatile organic compounds (VOCs) in different indoor microenvironments of residential homes and hostels in an academic institute, in New Delhi, during March-May 2011. Eleven VOCs (aromatic and halogenated) were assessed. Sampling and analytical procedure were based on National Institute for Occupational Safety and Health (NIOSH) standard method. The lifetime cancer and non-cancer risk were calculated for targeted VOCs using US Environmental Protection Agency guidelines. The mean concentrations of ∑ VOCs (sum of monitored VOCs) and individual VOC were found to be higher indoors as compared to outdoors at both types of premises. Indoor to outdoor (I/O) ratios of the targeted VOCs exceeded 1.0, suggesting the significant presence of indoor sources. Strong correlations between I/O concentrations of VOCs in the current study suggest the presence of common sources. Factor analysis (FA) was used for source evaluation separately at two premise types. The estimated lifetime cancer risks in the current study for all occupants at both premises exceeded 10(-6) .

Biogenic and anthropogenic isoprene in the near-surface urban atmosphere--a case study in Essen, Germany

Isoprene is emitted in large quantities by vegetation, exhaled by human beings and released in small quantities by road traffic. As a result of its high reactivity, isoprene is an important ozone precursor in the troposphere and can play a key role in atmospheric chemistry. Measurements of isoprene in urban areas in Central Europe are scarce. Thus, in Essen, Germany, the isoprene concentration was measured at various sites during different seasons using two compact online GC-PID systems. Isoprene concentrations were compared with those of benzene and toluene, which represent typical anthropogenic VOCs. In the summer, the diurnal variation in isoprene concentration was dependent on the biogenic emissions in the city. It was found that its maximum concentration occurred during the day, in contrast to the benzene and toluene concentrations. During the measurement period in the summer of 2012, the average hourly isoprene concentrations reached 0.13 to 0.17 ppb between 10 and 20 LST. At high air temperatures, the isoprene concentration exceeded the benzene and toluene concentrations at many of the sites. Isoprene became more important than toluene with regard to ozone formation in the city area during the afternoon hours of summer days with high air temperatures. This finding was demonstrated by the contributions to OH reactivity and ozone-forming potential. It contradicts the results of other studies, which were based on daily or seasonal average values. With an isoprene/benzene ratio of 0.02, the contribution of anthropogenic isoprene decreased substantially to a very low level during the last 20 years in Central Europe due to a strong reduction in road traffic emissions. In the vicinity of many people, isoprene concentrations of up to 0.54 ppb and isoprene/benzene ratios of up to 1.34 were found in the atmosphere due to isoprene exhaled by humans.

Assessment of indoor air concentrations of VOCs and their associated health risks in the library of Jawaharlal Nehru University, New Delhi

The present work investigated the levels of total volatile organic compounds (TVOC) and benzene, toluene, ethylbenzene, m/p-xylene, and o-xylene (BTEX) in different microenvironments in the library of Jawaharlal Nehru University in summer and winter during 2011-2012. Carcinogenic and non-carcinogenic health risks due to organic compounds were also evaluated using US Environmental Protection Agency (USEPA) conventional approaches. Real-time monitoring was done for TVOC using a data-logging photo-ionization detector. For BTEX measurements, the National Institute for Occupational Safety and Health (NIOSH) standard method which consists of active sampling of air through activated charcoal, followed by analysis with gas chromatography, was performed. Simultaneously, outdoor measurements for TVOC and BTEX were carried out. Indoor concentrations of TVOC and BTEX (except benzene) were higher as compared to the outdoor for both seasons. Toluene and m/p-xylene were the most abundant organic contaminant observed in this study. Indoor to outdoor (I/O) ratios of BTEX compounds were generally greater than unity and ranged from 0.2 to 8.7 and 0.2 to 4.3 in winter and summer, respectively. Statistical analysis and I/O ratios showed that the dominant pollution sources mainly came from indoors. The observed mean concentrations of TVOC lie within the second group of the Molhave criteria of indoor air quality, indicating a multifactorial exposure range. The estimated lifetime cancer risk (LCR) due to benzene in this study exceeded the value of 1 × 10(-6) recommended by USEPA, and the hazard quotient (HQ) of non-cancer risk came under an acceptable range.

The health significance of gas- and particle-phase terpene oxidation products: a review

The reactions between terpenes and ozone (or other oxidants) produce a wide variety of both gas- and particle-phase products. Terpenes are biogenic volatile organic compounds (VOCs) that are also contained in many consumer products. Ozone is present indoors since it infiltrates into the indoor environment and is emitted by some office and consumer equipment. Some of the gaseous products formed are irritating to biological tissues, while the condensed-phase products have received attention due to their contribution to ambient fine particulate matter (PM2.5) and its respective health significance. Despite common scientific questions, the indoor and ambient air research communities have tended to operate in isolation regarding this topic. This review critically evaluates the literature related to terpene oxidation products and attempts to synthesize results of indoor and ambient air studies to better understand the health significance of these materials and identify knowledge gaps. The review documents the results of a literature search covering terpene oxidation chemistry, epidemiological, toxicological, and controlled human exposure studies, as well as health studies focused more generically on secondary organic aerosol (SOA). The literature shows a clear role for gas-phase terpene oxidation products in adverse airway effects at high concentrations; however, whether these effects occur at more environmentally relevant levels is unclear. The evidence for toxicity of particle-phase products is less conclusive. Knowledge gaps and future research needs are outlined, and include the need for more consistency in study designs, incorporation of reaction product measurements into epidemiological studies conducted in both indoor and ambient settings, and more focused research on the toxicity of SOA, especially SOA of biogenic origin.