Volatile Organic Compounds (VOCs) in Conventional and High Performance School Buildings in the U.S

Investigation on the source of VOCs emission from indoor construction materials using electronic sensors and TD-GC-MS

Indoor air quality (IAQ) is critical to the health and wellbeing of people. As the majority of people spend greater amounts of time indoors, either in office spaces or households, the level of air pollutants in such environments is critical. Building materials and furniture are known sources of air pollutants such as Volatile Organic Compounds (VOCs) and may be associated with discomfort, detrimental health of the occupants, etc. In this study, the VOCs found in a brand new office complex were monitored over a period of 6 months, with an emphasis on monitoring and quantifying harmful VOCs and identifying their emission source. Air samples were taken from a closed, unoccupied office space on a weekly basis and analysed using Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS), while continuous monitoring of the air quality was performed using two commercially available IAQ sensors. To identify the source of the emitted VOCs, pieces of all construction material that were used in the office, including flooring, finished wall material, and adhesive glues, were removed, and placed in air-tight glass containers prior to analysis confirming that the source of VOCs is indeed the flooring. Identified compounds included mainly material origin VOCs such as BTEX (benzene, toluene, ethylbenzene, xylene) and styrene, but also common VOCs such as acetone and propan-2-ol. Of significant importance was the concentration of toluene that was found to be the most abundant VOC in both the flooring material and the indoor air.

Impact of Climate Change on Indoor Air Quality

Climate change may affect the quality of the indoor environment through heat and mass transfer between indoors and outdoors: first by a direct response to global warming itself and related extreme weather phenomena and second by indirect actions taken to reduce greenhouse gas emissions that can lead to increased concentrations of indoor air contaminants. Therefore, both indoor and outdoor air pollution contribute to poor indoor air quality in this context. Exposures to high concentrations of these pollutants contribute to inflammatory respiratory diseases. Climate change adaptation and mitigation measures could minimize these risks and bring associated health benefits.

Microglial NF-κB Signaling Deficiency Protects Against Metabolic Disruptions Caused by Volatile Organic Compound via Modulating the Hypothalamic Transcriptome

Prolonged exposure to benzene, a prevalent volatile organic compound (VOC), at concentrations found in smoke, triggers hyperglycemia, and inflammation in mice. Corroborating this with existing epidemiological data, we show a strong correlation between environmental benzene exposure and metabolic impairments in humans. To uncover the underlying mechanisms, we employed a controlled exposure system and continuous glucose monitoring (CGM), revealing rapid blood glucose surges and disturbances in energy homeostasis in mice. These effects were attributed to alterations in the hypothalamic transcriptome, specifically impacting insulin and immune response genes, leading to hypothalamic insulin resistance and neuroinflammation. Moreover, benzene exposure activated microglial transcription characterized by heightened expression of IKKβ/NF-κB-related genes. Remarkably, selective removal of IKKβ in immune cells or adult microglia in mice alleviated benzene-induced hypothalamic gliosis, and protected against hyperglycemia. In summary, our study uncovers a crucial pathophysiological mechanism, establishing a clear link between airborne toxicant exposure and the onset of metabolic diseases.

Volatile Organic Compounds in Disposable Diapers and Baby Wipes in the US: A Survey of Products and Health Risks

Many thousands of diapers are worn by young children and the elderly, who have thin and sensitive skin that is highly vulnerable to chemicals, including volatile organic compounds (VOCs) that may be ingredients of these products or present as inadvertent or residual components. The levels and potential health risks of VOCs in diapers have not been reported previously. In this study, we collected 31 disposable hygiene products in the US market based on market share and analyzed 98 target VOCs using purge and trap sampling and thermal desorption/gas chromatography/mass spectrometer analysis. Exposures and risks were modeled using reasonable upper level exposure scenarios. Adult diapers contained the highest total target VOC concentration (median level of 23.5 μg/g), and the predominant VOCs were alkanes. In some diapers, the estimated noncancer risk from these VOCs was sometimes very large (hazard quotient of 1609) due to n-heptane. Baby diapers contained several known or suspected carcinogens, including benzene and 1,4-dioxane, and the lifetime cancer risk from some diapers approached 1 per million under a worst-case scenario. Store-brand products had higher levels of VOCs than generic brands, and products labeled "organic" or "for sensitive skin" did not necessarily have lower levels. Our results show that toxic VOCs were found in all tested disposable diapers and wipes at trace levels, and risks from using some diapers in high use exposure scenarios are high enough to warrant additional attention and possibly corrective measures. We recommend eliminating and monitoring toxic ingredients and disclosing all chemicals that may be in these products.

A systematic review on mitigation of common indoor air pollutants using plant-based methods: a phytoremediation approach

Environmental pollution, especially indoor air pollution, has become a global issue and affects nearly all domains of life. Being both natural and anthropogenic substances, indoor air pollutants lead to the deterioration of the ecosystem and have a negative impact on human health. Cost-effective plant-based approaches can help to improve indoor air quality (IAQ), regulate temperature, and protect humans from potential health risks. Thus, in this review, we have highlighted the common indoor air pollutants and their mitigation through plant-based approaches. Potted plants, green walls, and their combination with bio-filtration are such emerging approaches that can efficiently purify the indoor air. Moreover, we have discussed the pathways or mechanisms of phytoremediation, which involve the aerial parts of the plants (phyllosphere), growth media, and roots along with their associated microorganisms (rhizosphere). In conclusion, plants and their associated microbial communities can be key solutions for reducing indoor air pollution. However, there is a dire need to explore advanced omics technologies to get in-depth knowledge of the molecular mechanisms associated with plant-based reduction of indoor air pollutants.

Volatile Organic Compounds in Finnish Office Environments in 2010-2019 and Their Relevance to Adverse Health Effects

We gathered recent (2010-2019) data on the VOC and formaldehyde levels in Finnish non-industrial indoor work environments. The data comprised 9789 VOC and 1711 formaldehyde samples collected from the indoor air of offices, schools, kindergartens, and healthcare offices. We assessed the health risks by comparing the measured concentrations to the health-based RW I/II and EU-LCI reference values. The concentrations of individual VOCs and formaldehyde in these work environments were generally very low and posed no health risks. Total VOC concentration (TVOC) as well as concentrations of several individual compounds, including aromatic compounds, alkanes, 2-ethyl-1-hexanol, and formaldehyde, showed clearly decreasing trends. In contrast, several aldehydes, acids, and a few other compounds showed increasing trends. However, the increasing trends did not seem to affect the higher ends of the distributions, as the 95th percentile values remained fairly stable or decreased over the years. The VOC patterns in the environments of the offices, schools, kindergartens, and healthcare offices varied, probably reflecting the differences in typical activities and the use of materials. However, we do not expect these differences to be relevant to health outcomes.

Understanding "Atmosome", the Personal Atmospheric Exposome: Comprehensive Approach

BACKGROUND

Modern environmental health research extensively focuses on outdoor air pollutants and their effects on public health. However, research on monitoring and enhancing individual indoor air quality is lacking. The field of exposomics encompasses the totality of human environmental exposures and its effects on health. A subset of this exposome deals with atmospheric exposure, termed the "atmosome." The atmosome plays a pivotal role in health and has significant effects on DNA, metabolism, skin integrity, and lung health.

OBJECTIVE

The aim of this work is to develop a low-cost, comprehensive measurement system for collecting and analyzing atmosomic factors. The research explores the significance of the atmosome in personalized and preventive care for public health.

METHODS

An internet of things microcontroller-based system is introduced and demonstrated. The system collects real-time indoor air quality data and posts it to the cloud for immediate access.

RESULTS

The experimental results yield air quality measurements with an accuracy of 90% when compared with precalibrated commercial devices and demonstrate a direct correlation between lifestyle and air quality.

CONCLUSIONS

Quantifying the individual atmosome is a monumental step in advancing personalized health, medical research, and epidemiological research. The 2 main goals in this work are to present the atmosome as a measurable concept and to demonstrate how to implement it using low-cost electronics. By enabling atmosome measurements at a communal scale, this work also opens up potential new directions for public health research. Researchers will now have the data to model the impact of indoor air pollutants on the health of individuals, communities, and specific demographics, leading to novel approaches for predicting and preventing diseases.

Assessing volatile organic compound level in selected workplaces of Kathmandu Valley

Volatile organic compounds (VOCs) are one of the major contributors to poor indoor air quality. Due to advancements in sensor technologies, continuous if not regular monitoring total VOC (TVOC) and or some specific VOC in potential high risk workplaces is possible even in resource limited settings. In this study, we implemented a portable VOC sensor to measure concentration of TVOC and formaldehyde (HCHO) in six types of potential high risk workplaces (n = 56 sites) of Katmandu Valley. For comparison, concentration was also measured in immediate surroundings (n = 56) of all the sites. To get preliminary information on safety practices, a survey study was also conducted. The mean TVOC and HCHO concentration in the sites ranged from 1.5‒8 mg/m³ and <0.01–5.5 mg/m³, respectively. The indoor: outdoor TVOC and HCHO ratio (I/O) was found to be significantly higher (I/O > 1.5 and p < 0.05) in 34 (~61%) and 47 sites (∼84%), respectively. A strong positive correlation between HCHO and TVOC concentration was observed in furniture industry (R = 0.91) and metal workshops (R = 0.98). Interestingly, we found TVOC and HCHO concentration higher than WHO safe limit in ∼64% and ∼32% sites, respectively. A rough estimate of chronic daily intake (CDI) of formaldehyde showed that CDI is higher than WHO limit in four sites. These findings suggested that indoor air quality in the significant number of the workplaces is poor and possible measures should be taken to minimize the exposure.

Volatile Organic Compounds in Primary Schools in Ho Chi Minh City, Vietnam: Characterization and Health Risk Assessment

Limited information about exposure to volatile organic compounds (VOCs) in primary schools in Vietnam is available. In this study, we aimed to characterize indoor VOCs in four primary schools situated in Ho Chi Minh City, a metropolis in the south of Vietnam and assess health risks linked to the students’ exposure to VOCs. Indoor and outdoor air samples were collected in the schools and analyzed for volatile composition using gas chromatography coupled with mass spectrometry. Different classes of VOCs, including aromatic hydrocarbons, alkanes, aldehydes, esters, cyclic terpenes, and chlorinated hydrocarbons, were identified and quantified in classrooms of the schools. The results showed that the concentrations of the VOCs differed significantly among the schools and between ground-floor and first floor classrooms. In addition, VOC profiles differed considerably between air-conditioned and non-air-conditioned classrooms. Limonene, a compound associated with fragrance products, was the most abundant VOC, with the median (range) concentration of 26.12 (10.29, 50.08) μg/m3. The concentrations of the compounds examined in the study were in general found to be higher indoors compared with outdoors, signifying indoor emission sources. Potential harmful effects are expected as a result of exposure to benzene, ethylbenzene, naphthalene, 1,4-dichlorobenzene and tetrachloroethylene in the investigated schools. Further research is needed to fully assess the health risks to students, teachers, and staff in these educational environments.

Limonene Emissions: Do Different Types Have Different Biological Effects?

Limonene is one of the most abundant pollutants indoors, and it contributes to the formation of additional pollutants, such as formaldehyde and photochemical smog. Limonene is commonly used in fragranced consumer products, such as cleaning supplies and air fresheners, which have also been associated with health problems. Limonene can exist in different enantiomeric forms (R-limonene and S-limonene) and be derived from different sources. However, little is known about whether different forms and sources of limonene may have different effects. This research explored whether different types of limonene, at the same concentrations, could elicit different biological effects. To investigate this question, the study employed Aedes aegypti mosquitoes, which have sophisticated olfactory abilities, in olfactometer tests of repellency/attraction. The results indicate that a synthetic source of R-limonene is more repellent than a natural source of R-limonene. In addition, synthetic sources of both R-limonene and S-limonene are not significantly different in repellency. These findings can contribute to our understanding and further exploration of the effects of a common fragrance compound on air quality and health.

Airborne volatile organic compounds at an e-waste site in Ghana: Source apportionment, exposure and health risks

Informal e-waste recycling processes emit various air pollutants. While there are a number of pollutants of concern, little information exists on volatile organic compounds (VOCs) releases at e-waste sites. To assess occupational exposures and estimate health risks, we measured VOC levels at the Agbogbloshie e-waste site in Ghana, the largest e-waste site in Africa, by collecting both fixed-site and personal samples for analyzing a wide range of VOCs. A total of 54 VOCs were detected, dominated by aliphatic and aromatic compounds. Mean and median concentrations of the total target VOCs were 46 and 37 μg/m³ at the fixed sites, and 485 and 162 μg/m³ for the personal samples. Mean and median hazard ratios were 2.1 and 1.4, respectively, and cancer risks were 4.6 × 10^-4 and 1.5 × 10^-4. These risks were predominantly driven by naphthalene and benzene; chloroform and formaldehyde were also high in some samples. Based on the VOC composition, the major sources were industry, fuel evaporation and combustion. The concentration gradient across sites and the similarity of VOC profiles indicated that the e-waste site emissions reached neighboring communities. Our results suggest the need to protect e-waste workers from VOC exposure, and to limit emissions that can expose nearby populations.

Novel Porous Carbon Material for the Detection of Traces of Volatile Organic Compounds in Indoor Air

A highly sensitive and selective silicon-based microanalytical prototype was used to identify a few ppb of volatile organic compounds (VOCs) in indoor air. Herein, a new nonactivated tannin-derived carbon synthesized by an environmentally friendly method, DM2C, a MIL-101(Cr) MOF, and a DaY zeolite were selected for the preconcentration of BTEX compounds (i.e., benzene, toluene, ethylbenzene, and xylenes). Integrating a small amount of these nanoporous solids inside a miniaturized preconcentration unit led to excellent preconcentration performance. By taking advantage of the high adsorption-desorption capacities of the DM2C adsorbent, concentrations as low as 23.5, 30.8, 16.7, 25, and 28.8 ppb of benzene, toluene, ethylbenzene, ortho- and para-xylene, respectively, were detected in a short analysis time (∼10 min) even in the presence of 60% relative humidity at 25 °C. The DM2C showed excellent stability over a period of 4 months and more than 500 tests, as well as repeatability, which makes it a very reliable adsorbent for the detection of trace VOCs in indoor air under realistic conditions in the presence of humidity.

Treatment of waste gas contaminated with dichloromethane using photocatalytic oxidation, biodegradation and their combinations

The treatment of waste gas (WG) containing dichloromethane (DCM) using advanced oxidation processes (AOPs) [UV and UV-TiO₂], biological treatment (BT), and their combination (AOPs-BT) was tested. AOP tests were performed in an annular photo-reactor (APHR), while BT was conducted in a continuous stirred tank bioreactor (CSTBR). The effects of gas flow rate (Q_gas), inlet DCM concentration ([DCM]_i), residence time (τ), photocatalyst loading (PH-C_L) and % relative humidity (% RH) on the AOPs performance and the removal of DCM (%DCM_r) were studied and optimized. The UV process exhibited %DCM_r ≤ 12.5 % for tests conducted at a [DCM]_i ≤ 0.45 g/m³, Q_gas of 0.12 m³/h and τ of 27.6 s, respectively, and < 4 % when the [DCM]_i ≥ 4.2 g/m³. The UV-TiO₂ achieved a %DCM_r ≥ 71 ± 1.5 % at Q_gas of 0.06 m³/h, [DCM]_i of 0.45 g/m³, τ of 55.2 s, PH-C_L of 10 g/m², and %RH of 50, respectively. The BT process removed ∼97.6 % of DCM with an elimination capacity (EC) of 234.0 g/m³·h. Besides, the high %DCM_r of ∼98.5 % in the UV-BT and 99.7 % in the UV-TiO₂-BT processes confirms AOPs-BT as a promising technology for the treatment of recalcitrant compounds present in WG.

A state-of-the-art review on indoor air pollution and strategies for indoor air pollution control

Indoor air pollution has traditionally received less attention than outdoors pollution despite indoors pollutant levels are typically twice higher, and people spend 80-90% of their life in increasing air-tight buildings. More than 5 million people die every year prematurely from illnesses attributable to poor indoor air quality, which also causes multi-millionaire losses due to reduced employee's productivity, material damages and increased health system expenses. Indoor air pollutants include particulate matter, biological pollutants and over 400 different chemical organic and inorganic compounds, whose concentrations are governed by several outdoor and indoor factors. Prevention of pollutant is not always technically feasible, so the implementation of cost-effective active abatement units is required. Up to date no single physical-chemical technology is capable of coping with all indoor air pollutants in a cost-effective manner. This problem requires the use of sequential technology configurations at the expenses of superior capital and operating costs. In addition, the performance of conventional physical-chemical technologies is still limited by the low concentrations, the diversity and the variability of pollutants in indoor environments. In this context, biotechnologies have emerged as a cost-effective and sustainable platform capable of coping with these limitations based on the biocatalytic action of plants, bacteria, fungi and microalgae. Indeed, biological-based purification systems can improve the energy efficiency of buildings, while providing additional aesthetic and psychological benefits. This review critically assessed the state-of-the-art of the indoor air pollution problem and prevention strategies, along with the recent advances in physical-chemical and biological technologies for indoor pollutants abatement.

Occupational exposure and health risks of volatile organic compounds of hotel housekeepers: Field measurements of exposure and health risks

Hotel housekeepers represent a large, low-income, predominantly minority, and high-risk workforce. Little is known about their exposure to chemicals, including volatile organic compounds (VOCs). This study evaluates VOC exposures of housekeepers, sources and factors affecting VOC levels, and provides preliminary estimates of VOC-related health risks. We utilized indoor and personal sampling at two hotels, assessed ventilation, and characterized the VOC composition of cleaning agents. Personal sampling of hotel staff showed a total target VOC concentration of 57 ± 36 µg/m3 (mean ± SD), about twice that of indoor samples. VOCs of greatest health significance included chloroform and formaldehyde. Several workers had exposure to alkanes that could cause non-cancer effects. VOC levels were negatively correlated with estimated air change rates. The composition and concentrations of the tested products and air samples helped identify possible emission sources, which included building sources (for formaldehyde), disinfection by-products in the laundry room, and cleaning products. VOC levels and the derived health risks in this study were at the lower range found in the US buildings. The excess lifetime cancer risk (average of 4.1 × 10-5 ) still indicates a need to lower exposure by reducing or removing toxic constituents, especially formaldehyde, or by increasing ventilation rates.

BTEX indoor air characteristic values in rural areas of Jordan: Heaters and health risk assessment consequences in winter season

Benzene, toluene, ethylbenzene, and xylene isomers (BTEX) are known to affect environmental air and health quality. In this study, the levels of BTEX compounds were determined in indoor air environments during the winter generated by several different heaters: diesel pot-bellied heater with chimney (DH); electric heater (EH); unfluted gas heater (GH); kerosene heater (KH); and wood pot-bellied heater with chimney (WH). The samples were collected using a diffusion passive adsorbent (activated charcoal) and then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the heaters differ in the quantity of BTEX released during operation. The KH was the most polluted heater based on BTEX measurement, followed by DH. The ∑BTEX for heaters were observed as follows: KH (290 μg m^-3); DH (120 μg m^-3); GH (84 μg m^-3); WH (31 μg m^-3); EH (16 μg m^-3). Toluene was the predominant compound in all air samples. In KH and DH, the toluene to benzene ratios (T/B) were higher than 4 due to fuel evaporation, while GH had a T/B ratio of 3.9, indicating that the combustion of liquefied petroleum gas (LPG) was the main source. Moreover, a risk assessment was performed to evaluate where the cancer risks (CR) for benzene and ethylbenzene exceeded the critical values (10^-6). KH was found to be the most harmful heater for residents, followed by DH and GH. For non-carcinogenic compounds, hazard quotients (HQ) were found to be less than one and thus unlikely to cause health problems.

Volatile organic compounds in feminine hygiene products sold in the US market: A survey of products and health risks

Feminine hygiene products (FHPs) are used on highly permeable and sensitive vaginal and vulvar tissues by many women. These products contain a variety of chemicals, and few regulations require disclosure of their ingredients. The objectives of this study are to identify volatile organic compounds (VOCs) that may be present in these products and to evaluate the potential for exposure and health risk associated with product use. We collected 79 commercially available FHPs, including washes, tampons, menstrual pads, wipes, sprays, powders and moisturizers, and analyzed their composition using purge and trap sampling, thermal desorption, gas chromatography and mass spectroscopy. Exposures and risks were modeled using reasonable upper bound exposure scenarios. The highest VOC concentrations (as total target VOCs) were found in washes, sprays and powders, with median concentrations from 25,000 to 34,000 ng/g. Benzene (maximum: 3,604 ng/g) was detected in 83% of the collected products, and 1,4-dioxane (maximum: 24,354 ng/g) in 50% of the products. VOC composition depended on the FHP type, manufacturer and brand. Products labeled as "organic," "natural," or "for sensitive skin" did not necessarily have lower VOC concentrations. For most FHPs, calculated risks were low; however, menstrual pads had hazard ratios of up to 11, sprays and powders had hazard ratios of up to 2.2 and excess cancer risks of up to 2.1 × 10^-6, and washes had excess cancer risks of up to 3.3 × 10^-6. Our data suggest that all tested FHPs contained some toxic VOCs, and that risks of using some products should be addressed. We recommend the elimination of toxic ingredients and the disclosure of all chemicals that are used in these products.

Exposure to indoor air contaminants in school buildings with and without reported indoor air quality problems

Reported indoor air quality (IAQ) complaints are common even in relatively new or renovated school buildings in Finland. However, detecting the causes for complaints with commonly used indoor air measurements is difficult. This study presents data on perceived and measured IAQ in six comprehensive school buildings in Finland. The aim of this study was to discover the possible differences of perceived and measured IAQ between schools with reported IAQ complaints and schools without reported IAQ complaints. The initial categorisation of schools with ('problematic schools') and without ('comparison schools') complaints was ensured via a validated indoor climate survey and a recently developed online questionnaire, which were completed by 186 teachers and 1268 students from the six schools. IAQ measurements of physical parameters, gaseous pollutants, particulate matter and bioaerosols were conducted in four problematic school buildings (26 classrooms) and two comparison school buildings (12 classrooms). Using air sampling as well as exhaust air filters and classroom settled dust to detect the presence of elevated concentrations of airborne cultivable microbes and pathogenic, toxigenic and mycoparasitic Trichoderma strains were the most indicative methods in distinguishing problematic schools from comparison schools. Other IAQ-related measurements did not detect clear differences between problematic and comparison schools, as the concentration levels were very low. The results indicate that the complaints reported by occupants could have been related to excess moisture or mould problems that had not been found or repaired. Ventilation pressure condition investigations and simultaneous exhaust and supply air filter dust culture should be addressed precisely in future studies.

Outdoor benzene highly impacts indoor concentrations globally

Benzene is a carcinogen. Exposure to benzene severely threatens people's health. While its indoor sources such as paint and solvent have been tightly regulated as a result of its inclusion into indoor air standards globally, its outdoor emission from traffic and industry is less addressed. Since human's exposure to benzene mainly occurs indoors, how outdoor benzene affects indoor concentrations is a critical issue, but not well discussed yet. This study summarized 118 pairs of outdoor-indoor measurement of benzene concentrations mainly published in the past five years. We found that the outdoor benzene concentrations measured in developing countries exceed 5 μg/m³, an annual concentration limit recommended by Europe Union, more often than developed ones. It implies a worse benzene pollution situation in the developing places, probably due to strong emission from traffic and industry. The outdoor/indoor concentration ratio is 0.69 and 0.84 for the developing and developed places, respectively. It indicates a significant, if not dominant, role of outdoor benzene in formulating indoor concentrations over indoor sources. Controlling outdoor benzene emission is therefore highlighted. Actions should be taken to regulate benzene emission sources such as traffic and industry. This is particularly urgent to protect occupants in buildings close to roads and factories.

Urban-level environmental factors related to pediatric asthma

During the 20th century, urbanization has increasing and represented a major demographic and environmental change in developed countries. This ever-changing urban environment has an impact on disease patterns and prevalence, namely on noncommunicable diseases, such as asthma and allergy, and poses many challenges to understand the relationship between the changing urban environment and the children health. The complex interaction between human beings and urbanization is dependent not only on individual determinants such as sex, age, social or economic resources, and lifestyles and behaviors, but also on environment, including air pollution, indoors and outdoors, land use, biodiversity, and handiness of green areas. Therefore, the assessment and identification of the impact of urban environment on children's health have become a priority and many recent studies have been conducted with the goal of better understanding the impacts related to urbanization, characterizing indoor air exposure, identifying types of neighborhoods, or characteristics of neighborhoods that promote health benefits. Thus, this review focuses on the role of urban environmental factors on pediatric asthma.

Indoor gaseous air pollutants determinants in office buildings-The OFFICAIR project

The aim of this study was to identify determinants of aldehyde and volatile organic compound (VOC) indoor air concentrations in a sample of more than 140 office rooms, in the framework of the European OFFICAIR research project. A large field campaign was performed, which included (a) the air sampling of aldehydes and VOCs in 37 newly built or recently retrofitted office buildings across 8 European countries in summer and winter and (b) the collection of information on building and offices' characteristics using checklists. Linear mixed models for repeated measurements were applied to identify the main factors affecting the measured concentrations of selected indoor air pollutants (IAPs). Several associations between aldehydes and VOCs concentrations and buildings' structural characteristic or occupants' activity patterns were identified. The aldehyde and VOC determinants in office buildings include building and furnishing materials, indoor climate characteristics (room temperature and relative humidity), the use of consumer products (eg, cleaning and personal care products, office equipment), as well as the presence of outdoor sources in the proximity of the buildings (ie, vehicular traffic). Results also showed that determinants of indoor air concentrations varied considerably among different type of pollutants.

Indoor Environmental Quality Evaluation of Lecture Classrooms in an Institutional Building in a Cold Climate

In this paper, ventilation, indoor air quality (IAQ), thermal and acoustic conditions, and lighting were studied to evaluate the indoor environmental quality (IEQ) in an institutional building at the University of Alberta in Edmonton, Canada. This study examined IEQ parameters, including pressure, illuminance, acoustics, carbon dioxide (CO2) concentration, temperature, and humidity, with appropriate monitors allocated during a lecture (duration 50 min or 80 min) in four lecture classrooms repeatedly (N = 99) from October 2018 to March 2019 with the objectives of providing a comprehensive analysis of interactions between IEQ parameters. The classroom environments were maintained at 23 ± 1 °C and 33% ± 3% RH during two-season measurements. Indoor mean CO2 concentrations were 550–1055 ppm, and a mean sound level of 58 ± 3 dBA was observed. The air change rates were configured at 1.3–6.5 per hour based on continuous CO2 measurements and occupant loads in the lectures. A variance analysis indicated that the within-lecture classroom variations in most IEQ parameters exceeded between-lecture classrooms. A multilayer artificial neural network (ANN) model was developed on the basis of feedforward networks with a backpropagation algorithm. ANN results demonstrated the importance of the sequence of covariates on indoor conditions (temperature, RH, and CO2 level): Air change rate (ACR) > room operations (occupant number and light system) > outdoor conditions.

Variability of Total Volatile Organic Compounds (TVOC) in the Indoor Air of Retail Stores

Volatile organic compounds (VOCs) are released to the indoor air of retail stores from numerous products and activities, but available literature lacks a systematic understanding of the variability of VOC concentrations. In this study, we measured concentrations of total VOCs (TVOC) in 32 retail stores using a high-sensitivity photoionization detector (PID). Indoor thermal comfort parameters, including temperature, relative humidity, and air velocity, were simultaneously measured using an anemometer. The store-level TVOC concentrations ranged from 30 to 869 ppb and exceeded the LEED guideline in 31 stores. TVOC levels were notably high in hardware stores (median = 536 ppb, p = 0.0002) and paints, household, and home accessories sections within stores (p < 0.05). TVOC levels were elevated in mornings and evenings, possibly due to low ventilation and cleaning activities at the beginning and end of business hours. The between-store, within-store, and temporal variations accounted for 85%, 0.5%, and 14% of the total variance, respectively. The variance structure suggested that in-store VOC concentrations were predominantly driven by their source location, and representative monitoring should first consider covering various store types. Current store VOC levels present health concerns, but further studies are needed to evaluate risks among customers.

From one species to another: A review on the interaction between chemistry and microbiology in relation to cleaning in the built environment

Since the advent of soap, personal hygiene practices have revolved around removal, sterilization, and disinfection-both of visible soil and microscopic organisms-for a myriad of cultural, aesthetic, or health-related reasons. Cleaning methods and products vary widely in their recommended use, effectiveness, risk to users or building occupants, environmental sustainability, and ecological impact. Advancements in science and technology have facilitated in-depth analyses of the indoor microbiome, and studies in this field suggest that the traditional "scorched-earth cleaning" mentality-that surfaces must be completely sterilized and prevent microbial establishment-may contribute to long-term human health consequences. Moreover, the materials, products, activities, and microbial communities indoors all contribute to, or remove, chemical species to the indoor environment. This review examines the effects of cleaning with respect to the interaction of chemistry, indoor microbiology, and human health.

Quantifying indoor air quality determinants in urban and rural nursery and primary schools

Poor indoor air quality can adversely affect children's health, comfort and school performance, but existing literature on quantifying indoor air pollutants (IAP) determinants' in nursery and primary schools is limited. Following previous studies, this study mainly aimed to quantify determinants of selected IAP, in nursery and primary schools from both urban and rural sites, accounting for seasonal variations. In 101 indoor microenvironments (classrooms, bedrooms and canteens) from 25 nursery and primary schools, CO₂, CO, HCOH, NO₂, O₃, total volatile organic compounds, PM₁, PM_2.5, PM₁₀, total suspended particles (TSP), and meteorological/comfort parameters were continuously sampled (occupancy and background levels), from at least 24 h to 9 consecutive days (not simultaneously) in each studied room; in some cases weekend was also considered. Children faced thermal discomfort and inadequate humidity, respectively in 60.1% and 44.1% of the studied classrooms. They were also exposed to high levels of IAP, namely PM_2.5 and CO₂ respectively in 69.0% and 41.3% of the studied classrooms, mostly in urban sites, depending on season and on occupancy and activity patterns (different amongst age groups). As PM_2.5 and CO₂ were the major concerning IAP, multivariate linear regression models were built to quantify (explained variability and relative importance) their main determinants, in both occupancy and non-occupancy (background) periods. Models for occupancy periods showed higher explained variability (R² = 0.64, 0.57 and 0.47, respectively, for CO₂, PM_2.5 and PM₁₀) than for non-occupancy. Besides background concentrations (43.5% of relative importance), relative humidity (21.1%), flooring material (17.0%), heating (6.7%) and age group of the occupants (5.3%), adjusted for season of sampling (6.4%) were predictors in CO₂ occupancy model. In the cases of PM_2.5 and PM₁₀ occupancy concentrations, besides background concentrations (71.2% and 67.2% of relative importance, respectively for PM_2.5 and PM₁₀), type of school management (8.8% and 15.2%) and flooring material (13.9% and 13.9%), adjusted for season of sampling (6.1% and 3.8%), were the main predictors. These findings support the need of mitigation measures to reduce IAP levels, and prevention actions to avoid children's exposure. Reducing the time spent indoors in the same microenvironment by doing more and/or longer breaks, improving ventilation and cleaning actions, and avoiding or making a better maintenance hardwood flooring materials, chalkboard use and VOC emitting materials, are practices that should be implemented and their impacts quantified.

Sub-ppb Level Detection of BTEX Gaseous Mixtures with a Compact Prototype GC Equipped with a Preconcentration Unit

In this work, a compact gas chromatograph prototype for near real-time benzene, toluene, ethylbenzene and xylenes (BTEX) detection at sub-ppb levels has been developed. The system is composed of an aluminium preconcentrator (PC) filled with Basolite C300, a 20 m long Rxi-624 capillary column and a photoionization detector. The performance of the device has been evaluated in terms of adsorption capacity, linearity and sensitivity. Initially, PC breakthrough time for an equimolar 1 ppm BTEX mixture has been determined showing a remarkable capacity of the adsorbent to quantitatively trap BTEX even at high concentrations. Then, a highly linear relationship between sample volume and peak area has been obtained for all compounds by injecting 100-ppb samples with volumes ranging from 5⁻80 mL. Linear plots were also observed when calibration was conducted in the range 0⁻100 ppb using a 20 mL sampling volume implying a total analysis time of 19 min. Corresponding detection limits of 0.20, 0.26, 0.49, 0.80 and 1.70 ppb have been determined for benzene, toluene, ethylbenzene, m/p-xylenes and o-xylene, respectively. These experimental results highlight the potential applications of our device to monitor indoor or outdoor air quality.

VOC sources and exposures in nail salons: a pilot study in Michigan, USA

PURPOSE

Exposures of nail salon technicians have received attention due to the potentially toxic materials used in nail products, which include volatile organic compounds (VOCs) such as formaldehyde and methyl methacrylate (MMA). This study characterized area and personal concentrations and other indoor air parameters in 17 nail salons in fall and winter seasons in three areas of Michigan.

METHODS

VOC samples were analyzed using thermal desorption, gas chromatography and mass spectroscopy, and the VOC composition of 35 nail products (e.g., polish, top coat, base coat) was measured using headspace sampling. Ventilation rates were derived using CO2 concentrations, occupancy and building information, and VOC sources were apportioned by a novel application of chemical mass balance models.

RESULTS

We detected ethyl acetate, propyl acetate, butyl acetate, MMA, n-heptane and toluene in most salons, and benzene, D-limonene, formaldehyde, and ethyl methacrylate in some salons. While MMA was not measured in the consumer and professional products, and the use of pure MMA in salons has been not been permitted since the 1970s, MMA was found in air at concentrations from 100 to 36,000 µg/m3 in 15 of 17 salons; thus its use appears to be commonplace in the industry. Personal measurements, representing exposures to workers and clients, were about twice those of the area measurements for many VOCs.

CONCLUSION

This study identifies the products responsible for emissions, shows the widespread presence of MMA, and documents low ventilation rates in some salons. It also demonstrates that "informal" short-term sampling approaches can evaluate chemical exposures in nail salons, providing measurements that can be used to protect a potentially susceptible and vulnerable population. Additional controls, including restrictions on the VOC compositions and improved ventilation, can reduce exposures to salon workers and clients.

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.