Biocide and other semi-volatile organic compound concentrations in settled indoor dust of CRESPI daycare centers and implication for public health

This study investigates the presence of biocides and other semi-volatile organic compounds (SVOCs) in cleaning products used in daycare centers and health impact through ingestion of settled dust by young children. In Paris metropolitan area, 106 daycares area were investigated between 2019-2022. Fifteen substances were analyzed in settled indoor dust by gas chromatography-tandem mass spectrometry. Detection rates and concentrations ranged from 5 to 100%, and Collapse

Key Words

• Day nurseries
• Dust ingestion
• Health relevance
• Oral exposure
• SVOCs

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MESH Headings

• Dust/analysis
• Humans
• Volatile Organic Compounds/analysis
• Child Day Care Centers
• Air Pollution, Indoor/analysis
• Disinfectants/analysis
• Infant
• Public Health
• Environmental Monitoring
• Child, Preschool

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Affiliation(s)

Mayoro Kebe Mane Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.
Gaëlle Raffy Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.
Philippe Glorennec Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.
Nathalie Bonvallot Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.
Pierre Bonnet Scientific and Technical Center for Building (CSTB), Indoor Environment Quality Unit, 77420 Champs-sur-Marne, France.
Orianne Dumas Université Paris-Saclay, UVSQ, Univ. Paris-Sud, Inserm, Équipe d'Épidémiologie Respiratoire Intégrative, CESP, 94807 Villejuif, France.
Anastasie Eworo Nchama Université Paris-Saclay, UVSQ, Univ. Paris-Sud, Inserm, Équipe d'Épidémiologie Respiratoire Intégrative, CESP, 94807 Villejuif, France.
Gaëlle Saramito Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.
Camille Duguépéroux Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.
Corinne Mandin Scientific and Technical Center for Building (CSTB), Indoor Environment Quality Unit, 77420 Champs-sur-Marne, France.
Nicole Le Moual Université Paris-Saclay, UVSQ, Univ. Paris-Sud, Inserm, Équipe d'Épidémiologie Respiratoire Intégrative, CESP, 94807 Villejuif, France.
Barbara Le Bot Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, F-35000 Rennes, France.

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Indoor exposure to ultrafine particles related to domestic activities: A systematic review and meta-analysis

Ultrafine particles (< 100 nm) are of increasing concern because of their toxicological potential. Emission processes suggest their presence in all environments, including at home, where particularly at-risk populations may be exposed. However, knowledge of their impact on health is still limited, due to difficulties in properly assessing exposure in epidemiological studies. In this context, the objective of this study was to provide a complete summary of indoor exposure to ultrafine particles in highly industrialised countries by examining the domestic activities that influence such exposure. We conducted a systematic review, according to PRISMA guidelines using PubMed, Web of Science and Scopus up to and including 2021. We carried out a qualitative and quantitative analysis of the selected studies with a standardised template. Exposure circumstances, measurement methods, and results were analysed. Finally, a meta-analysis of the measured concentrations was performed to study exposure levels during domestic activities. The review included 69 studies resulting in the analysis of 346 exposure situations. Nine main groups of activities were identified: cooking, which was the most studied, smoking, the use of air-fresheners, cleaning, heating, personal care, printing, do-it-yourself activities, and others. Over 50 different processes were involved in these activities. Based on available particle number concentrations, the highest average of mean concentrations was associated with grilling (14,400 × 103 cm-3), and the lowest with wood stove (18 × 103 cm-3). The highest average of peak concentrations was that for the use of hair dryers (695 × 103 cm-3), and the lowest for the use of air cleaners (11 × 103 cm-3). A hierarchy of domestic activities and related processes leading to ultrafine particle exposure is provided, along with average exposure concentrations at home. However, more extensive measurement campaigns are needed under real-life conditions to improve assessments of indoor exposure to ultrafine particles.

The burden of disease attributable to indoor air pollutants in China from 2000 to 2017

BACKGROUND

High-level exposure to indoor air pollutants (IAPs) and their corresponding adverse health effects have become a public concern in China in the past 10 years. However, neither national nor provincial level burden of disease attributable to multiple IAPs has been reported for China. This is the first study to estimate and rank the annual burden of disease and the financial costs attributable to targeted residential IAPs at the national and provincial level in China from 2000 to 2017.

METHODS

We first did a systematic review and meta-analysis of 117 articles from 37 231 articles identified in major databases, and obtained exposure-response relationships for the candidate IAPs. The exposure levels to these IAPs were then collected by another systematic review of 1864 articles selected from 52 351 articles. After the systematic review, ten IAPs with significant and robust exposure-response relationships and sufficient exposure data were finally targeted: PM2·5, nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide, radon, formaldehyde, benzene, toluene, and p-dichlorobenzene. The annual exposure levels in residences were then evaluated in all 31 provinces in mainland China continuously from 2000 to 2017, using the spatiotemporal Gaussian process regression model to analyse indoor originating IAPs, and the infiltration factor method to analyse outdoor originating IAPs. The disability-adjusted life-years (DALYs) attributable to the targeted IAPs were estimated at both national and provincial levels in China, using the population attributable fraction method. Financial costs were estimated by an adapted human capital approach.

FINDINGS

From 2000 to 2017, annual DALYs attributable to the ten IAPs in mainland China decreased from 4620 (95% CI 4070-5040) to 3700 (3210-4090) per 100 000. Nevertheless, in 2017, IAPs still ranked third among all risk factors, and their DALYs and financial costs accounted for 14·1% (95% CI 12·3-15·6) of total DALYs and 3·45% (3·01-3·82) of the gross domestic product. Specifically, the rank of ten targeted IAPs in order of their contribution to DALYs in 2017 was PM2·5, carbon monoxide, radon, benzene, nitrogen dioxide, ozone, sulphur dioxide, formaldehyde, toluene, and p-dichlorobenzene. The DALYs attributable to IAPs were 9·50% higher than those attributable to outdoor air pollution in 2017. For the leading IAP, PM2·5, the DALYs attributable to indoor origins are 18·3% higher than those of outdoor origins.

INTERPRETATION

DALYs attributed to IAPs in China have decreased by 20·0% over the past two decades. Even so, they are still much higher than those in the USA and European countries. This study can provide a basis for determining which IAPs to target in various indoor air quality standards and for estimating the health and economic benefits of various indoor air quality control approaches, which will help to reduce the adverse health effects of IAPs in China.

FUNDING

The National Key Research and Development Program of China and the National Natural Science Foundation of China.

Exposure to Disinfectants and Cleaning Products and Respiratory Health of Workers and Children in Daycares: The CRESPI Cohort Protocol

Although cleaning tasks are frequently performed in daycare, no study has focused on exposures in daycares in relation to respiratory health. The CRESPI cohort is an epidemiological study among workers (n~320) and children (n~540) attending daycares. The purpose is to examine the impact of daycare exposures to disinfectants and cleaning products (DCP) on the respiratory health of workers and children. A sample of 108 randomly selected daycares in the region of Paris has been visited to collect settled dust to analyze semi-volatile organic compounds and microbiota, as well as sample indoor air to analyze aldehydes and volatile organic compounds. Innovative tools (smartphone applications) are used to scan DCP barcodes in daycare and inform their use; a database then matches the barcodes with the products' compositions. At baseline, workers/parents completed a standardized questionnaire, collecting information on DCP used at home, respiratory health, and potential confounders. Follow-up regarding children's respiratory health (monthly report through a smartphone application and biannual questionnaires) is ongoing until the end of 2023. Associations between DCP exposures and the respiratory health of workers/children will be evaluated. By identifying specific environments or DCP substances associated with the adverse respiratory health of workers and children, this longitudinal study will contribute to the improvement of preventive measures.

Use and storage of pesticides at home in France (the Pesti'home survey 2014)

Some epidemiological studies have raised health concerns following the chronic exposure of pregnant women and children to pesticides in the domestic environment. In France very little is known about potential exposure to pesticides at home. An observational study called Pesti'home was carried out in continental France between July and November 2014. The residential use of pesticides was investigated and an inventory of pesticides and active ingredients used and stored at home was drawn up. Plant protection products, biocides, and human and animal external pest control products were listed during face-to-face interviews. A random sample of households including at least one adult (18-79 years old) was selected following a two-stage stratified random sampling method using the national census database. Within each household, an adult was appointed to answer survey questions. Data related to the interviewee's sociodemographic and housing characteristics, the reported use of pesticides at home, and a visual inventory of all stored pesticides were collected. Overall, 1507 households participated. The participation rate was between 36% and 57% according to the definition chosen. Over the previous 12 months, 75% of households declared that they had used at least one pesticide. Households who used and stored at least one product most frequently used an insecticide (84%). The active ingredients most frequently used by these households as insecticides were pyrethroids, namely tetramethrin and permethrin. The Pesti'home survey collected detailed data on the residential use of pesticides for risk assessment at national and European levels.

Impact of Climate Change on Indoor Air Quality: A Review

Climate change can affect the indoor environment due to heat and mass transfers between indoor and outdoor environments. To mitigate climate change impacts and adapt buildings to the changing environment, changes in building characteristics and occupants' behavior may occur. To characterize the effects of climate change on indoor air quality (IAQ), the present review focused on four aspects: (1) experimental and modeling studies that relate IAQ to future environmental conditions, (2) evolution of indoor and outdoor air concentrations in the coming years with regard to temperature rise, (3) climate change mitigation and adaptation actions in the building sector, and (4) evolution of human behavior in the context of climate change. In the indoor environment, experimental and modeling studies on indoor air pollutants highlighted a combined effect of temperature and relative humidity on pollutant emissions from indoor sources. Five IAQ models developed for future climate data were identified in the literature. In the outdoor environment, the increasing ambient temperature may lead directly or indirectly to changes in ozone, particle, nitrogen oxides, and volatile organic compound concentrations in some regions of the world depending on the assumptions made about temperature evolution, anthropogenic emissions, and regional regulation. Infiltration into buildings of outdoor air pollutants is governed by many factors, including temperature difference between indoors and outdoors, and might increase in the years to come during summer and decrease during other seasons. On the other hand, building codes in some countries require a higher airtightness for new and retrofitted buildings. The building adaptation actions include the reinforcement of insulation, implementation of new materials and smart building technologies, and a more systematic and possibly longer use of air conditioning systems in summer compared to nowadays. Moreover, warmer winters, springs, and autumns may induce an increasing duration of open windows in these seasons, while the use of air conditioning in summer may reduce the duration of open windows.

Modeling Primary Emissions of Chemicals from Liquid Products Applied on Indoor Surfaces

Liquid products applied on material surfaces and human skin, including many household cleaning products and personal care products, can lead to intermittent emissions of chemicals and peak concentrations in indoor air. The existing case-based models do not allow inter-comparison of different use scenarios and emission mechanisms. In this context, the present work developed a mechanistic model based on mass transfer theories, which allowed emissions into the air from the liquid product to be characterized. It also allowed for diffusion into the applied surface during product use and re-emission from the applied surface after the depletion of the liquid product. The model was validated using literature data on chemical emissions following floor cleaning and personal care product use. A sensitivity analysis of the model was then conducted. The percentage of the chemical mass emitted from the liquid to the air varied from 45% (applied on porous material) to 99% (applied on human skin), and the rest was absorbed into the applied material/skin. The peak gas-phase concentration, the time to reach the peak concentration, and the percentage of the liquid-to-air emission depended significantly on the chemical's octanol/gas and material/gas partition coefficients and the diffusion coefficient of the chemical in the applied material/skin.

Indoor air quality in shopping and storage areas

In retail stores, workers are constantly exposed to new manufactured goods. The issue of the exposure of retail workers to volatile organic compounds (VOCs) should clearly be considered. Therefore, this study provides data regarding VOC concentrations in ten French retail stores. The stores were chosen to represent various products: sports goods, shoes and leather, furniture, car equipment, bazaars, online-sales storage, clothes, books, DIY (do-it-yourself), and household appliances. VOCs and aldehydes were actively sampled on the same day in five to seven locations per building and outdoors. Toluene and formaldehyde were omnipresent with indoor concentrations reaching 252 and 53 µg/m³ , respectively. The car equipment store, followed by clothing, shoes, and leather, and DIY stores showed the worst indoor air quality. High concentrations were measured, for example, the maximum α-pinene concentration in the furniture and DIY stores was 364 and 141 µg/m³ , respectively, and the heptane concentration in the car equipment store reached 1,316 µg/m³ . Two VOCs classified as toxic to reproduction were measured: hexane in the car equipment store and the bazaar, and dimethylformamide in the sports goods store. This study shows some disparities in the indoor concentrations among different locations in the same store, particularly between sales and storage areas.

Indoor air pollutant health prioritization in office buildings

This work presents an original method to identify priority indoor air pollutants in office buildings. It uses both a chronic risk assessment approach by calculating a hazard quotient, and a hazard classification method based on carcinogenic, mutagenic, reprotoxic, and endocrine disruptive effects. A graphical representation of the results provides a comprehensive and concise visualization of all of the information, including the number of buildings where each substance was measured, an indicator of exposure data robustness. Seventy-one out of 342 substances (20%) for which indoor air concentrations have already been measured in office buildings were identified as priority pollutants. The results were compared to previous prioritization studies in various types of indoor environments to assess the reliability of the method and highlight its advantages. Sensitivity analyses were performed to reduce the geographical scope (OECD countries only), time scope (after 2010 only), and measurement duration (working hours only) and showed little influence on the results. Finally, 123 additional substances that could be present in office indoor air but could not be assessed due to the lack of measurement data are proposed for future monitoring surveys to update the prioritization of indoor air pollutants in offices.

Association of subjective health symptoms with indoor air quality in European office buildings: The OFFICAIR project

The aim of this study was to explore the association between the building-related occupants' reported health symptoms and the indoor pollutant concentrations in a sample of 148 office rooms, within the framework of the European OFFICAIR research project. A large field campaign was performed in 37 office buildings among eight countries, which included (a) 5-day air sampling of volatile organic compounds (VOCs), aldehydes, ozone, and NO₂ (b) collection of information from 1299 participants regarding their personal characteristics and health perception at workplace using online questionnaires. Stepwise and multilevel logistic regressions were applied to investigate associations between health symptoms and pollutant concentrations considering personal characteristics as confounders. Occupants of offices with higher pollutant concentrations were more likely to report health symptoms. Among the studied VOCs, xylenes were associated with general (such as headache and tiredness) and skin symptoms, ethylbenzene with eye irritation and respiratory symptoms, a-pinene with respiratory and heart symptoms, d-limonene with general symptoms, and styrene with skin symptoms. Among aldehydes, formaldehyde was associated with respiratory and general symptoms, acrolein with respiratory symptoms, propionaldehyde with respiratory, general, and heart symptoms, and hexanal with general SBS. Ozone was associated with almost all symptom groups.

Assessing Human Exposure to SVOCs in Materials, Products, and Articles: A Modular Mechanistic Framework

A critical review of the current state of knowledge of chemical emissions from indoor sources, partitioning among indoor compartments, and the ensuing indoor exposure leads to a proposal for a modular mechanistic framework for predicting human exposure to semivolatile organic compounds (SVOCs). Mechanistically consistent source emission categories include solid, soft, frequent contact, applied, sprayed, and high temperature sources. Environmental compartments are the gas phase, airborne particles, settled dust, indoor surfaces, and clothing. Identified research needs are the development of dynamic emission models for several of the source emission categories and of estimation strategies for critical model parameters. The modular structure of the framework facilitates subsequent inclusion of new knowledge, other chemical classes of indoor pollutants, and additional mechanistic processes relevant to human exposure indoors. The framework may serve as the foundation for developing an open-source community model to better support collaborative research and improve access for application by stakeholders. Combining exposure estimates derived using this framework with toxicity data for different end points and toxicokinetic mechanisms will accelerate chemical risk prioritization, advance effective chemical management decisions, and protect public health.

Semivolatile organic compounds in French schools: Partitioning between the gas phase, airborne particles and settled dust

The indoor environmental quality in classrooms can largely affect children's daily exposure to indoor chemicals in schools. To date, there has not been a comprehensive study of the concentrations of semivolatile organic compounds (SVOCs) in French schools. Therefore, the French Observatory for Indoor Air Quality (OQAI) performed a field study of SVOCs in 308 nurseries and elementary schools between June 2013 and June 2017. The concentrations of 52 SVOCs, including phthalates, polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), synthetic musks, and pesticides, were measured in air and settled dust (40 SVOCs in both air and dust, 12 in either air or dust). The results showed that phthalates had the highest concentrations among the SVOCs in both the air and dust. Other SVOCs, including tributyl phosphate, fluorene, phenanthrene, gamma-hexachlorocyclohexane (gamma-HCH, lindane), galaxolide, and tonalide, also showed high concentrations in both the air and dust. Theoretical equations were developed to estimate the SVOC partitioning between the air and settled dust from either the octanol/air partition coefficient or the boiling point of the SVOCs. The regression constants of the equations were determined using the data set of the present study for phthalates and PAHs.

Toward setting public health guidelines for chemicals in indoor settled dust?

Indoor settled dust may result in substantial human exposure to chemicals, especially by ingestion following hand-to-mouth or hand-to-object-to-mouth contact. As with other environmental media related to exposure, dust may thus be subject to regulation. An international scientific workshop was convened in Paris in September 2019 firstly to assess the relevance for public health of setting guidelines for indoor settled dust, and secondly to discuss scientific and technical challenges related to such guidelines. The main discussions and conclusions, with consensus achieved, are reported herein. Discussions concerned general considerations, objectives and definitions, relevance for a health-based guideline, units of measure, and finally derivation of the guideline. These points should be addressed when considering an indoor settled dust guideline as part of a policy to reduce exposure indoors to a given chemical or group of chemicals.

Daylight and School Performance in European Schoolchildren

Aims and objectives: Lighting constitutes a critical issue in school design because of its importance as a strong enabler of performance, which is crucial for child development. However, data on light impacts on school performance are scarce. The main objective of this study was to assess the relationship between daylighting conditions in classrooms and mathematical and logical test scores. Methods: The population-based SINPHONIE (Schools Indoor Pollution and Heath: Observatory Network in Europe) study provides information on relationships between lighting conditions and school performance for 2670 elementary schoolchildren, aged 8–13 years from 155 classrooms in 53 schools across 12 European countries. These data were acquired through direct physical assessments and questionnaires completed by teachers, schoolchildren, and their parents, allowing for estimations of multiple objective daylight indicators, as well as subjective parameters such as the perception of lighting. Schoolchildren performed an attention/concentration exam that included simple mathematical exercises in addition to a logical ciphering test. The corresponding performance scores were compared against multiple daylighting parameters. Results: A positive relationship was found between performance scores and type of window shading, latitude, percentage of window facing south, and window glazing, with the highest impact due to the window-to-floor area ratio. Conclusion: Data collected in the SINPHONIE study across 12 European countries indicate that daylighting parameters are relevant to schoolchildren’s performance. As SINPHONIE was not designed specifically with lighting in mind, dedicated studies covering a wide range of classroom configurations would be enlightening.

Predicting the rate constants of semivolatile organic compounds with hydroxyl radicals and ozone in indoor air

Semivolatile organic compounds (SVOCs) in air can react with hydroxyl radicals (OH), nitrate radicals (NO₃) and ozone (O₃). Two questions regarding SVOC reactivity with OH, NO₃ and O₃ in the gas and particle phases remain to be addressed: according to the existing measurements in the literature, which are the most reactive SVOCs in air, and how can the SVOC reactivity in the gas and particle phases be predicted? In the present study, a literature review of the second-order rate constant (k) was carried out to determine the SVOC reactivity with OH, NO₃ and O₃ in the gas and particle phases in ambient and indoor air at room temperature. Measured k values were available in the literature for 90 polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organophosphates, dioxins, di(2-ethylhexyl)phthalate (DEHP) and pesticides including pyrifenox, carbamates and terbuthylazine. PAHs and organophosphates were found to be more reactive than dioxins and PCBs. Based on the obtained data, quantitative structure-activity relationship (QSAR) models were developed to predict the k value using quantum chemical, molecular, physical property and environmental descriptors. Eight linear and nonlinear statistical models were employed, including regression models, bagging, random forest and gradient boosting. QSAR models were developed for SVOC/OH reactions in the gas and particle phases and SVOC/O₃ reactions in the particle phase. Models for SVOC/NO₃ and SVOC/O₃ reactions in the gas phase could not be developed due to the lack of measured k values for model training. The least absolute shrinkage and selection operator (LASSO) regression and random forest models were identified as the most effective models for SVOC reactivity prediction according to a comparison of model performance metrics.

Aggregate and cumulative chronic risk assessment for pyrethroids in the French adult population

Pyrethroids are commonly used as insecticides in households, in agriculture or in veterinary and medicinal products. This study aimed to assess cumulative aggregate exposure to cyfluthrin, cypermethrin, deltamethrin and permethrin in adults in France and the associated health risk, and to identify major contributions of exposure sources and routes. External chronic exposures were estimated from dietary and several environmental sources for the oral, inhalation and dermal routes. Internal concentrations of five associated metabolites were simulated with a physiologically-based pharmacokinetic model. The predicted urinary concentrations were in same order of magnitude as those of the French ENNS biomonitoring survey. Dietary exposure, especially from cereals and animal products, was the major source of exposure. For the 1% of adults most highly exposed, dermal exposure to permethrin through medicinal and veterinary products was an important source of exposure. Considering alterations of motor, sensory and autonomic division, all individual margins of exposure were higher than 100, suggesting that no neurotoxic risk associated with the cumulative aggregate exposure to these four pyrethroids is expected for the French adult population.

Modeling the bioaccessibility of inhaled semivolatile organic compounds in the human respiratory tract

The bioaccessibility of semivolatile organic compounds (SVOCs) via inhalation has rarely been studied, as indicated by the literature. There is no model to calculate the SVOC bioaccessibility following inhalation, and measurement data have focused on only a few polycyclic aromatic hydrocarbons (PAHs) in the particle phase. The present work developed a mechanistic model to address the mass transfer of inhaled SVOCs among the gas, particle and mucus phases in the human respiratory tract. The model considers (1) the SVOC partitioning between the gas and particle phases as well as between the gas and mucus phases and (2) the deposition of gas- and particle-phase SVOCs in the mucus of the respiratory tract. Based on the model, the inhalation bioaccessibility for 72 SVOCs was calculated. The SVOCs were measured in French dwellings at the nationwide scale, and their median concentrations in both the gas and particle phases were used for the bioaccessibility calculations. The results show that the inhalation bioaccessibility varies considerably from one compound to another, e.g., between 0.62 and 1.00 for phthalates, between 0.71 and 0.79 for polybrominated diphenyl ethers (PBDEs), between 0.48 and 0.56 for polychlorinated biphenyls (PCBs), between 0.48 and 1.00 for different chemical families of pesticides and between 0.48 and 0.90 for PAHs.

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.

Machine learning and statistical models for predicting indoor air quality

Indoor air quality (IAQ), as determined by the concentrations of indoor air pollutants, can be predicted using either physically based mechanistic models or statistical models that are driven by measured data. In comparison with mechanistic models mostly used in unoccupied or scenario-based environments, statistical models have great potential to explore IAQ captured in large measurement campaigns or in real occupied environments. The present study carried out the first literature review of the use of statistical models to predict IAQ. The most commonly used statistical modeling methods were reviewed and their strengths and weaknesses discussed. Thirty-seven publications, in which statistical models were applied to predict IAQ, were identified. These studies were all published in the past decade, indicating the emergence of the awareness and application of machine learning and statistical modeling in the field of IAQ. The concentrations of indoor particulate matter (PM_2.5 and PM₁₀ ) were the most frequently studied parameters, followed by carbon dioxide and radon. The most popular statistical models applied to IAQ were artificial neural networks, multiple linear regression, partial least squares, and decision trees.

Semi-volatile organic compounds in French dwellings: An estimation of concentrations in the gas phase and particulate phase from settled dust

Semi-volatile organic compounds (SVOCs) are present in the gas phase, particulate phase and settled dust in the indoor environment, resulting in human exposure through different pathways. Sometimes, SVOCs are only measured in a single phase because of practical and/or financial constraints. A probabilistic method proposed by Wei et al. for the prediction of the SVOC concentration in the gas phase from the SVOC concentration in the particulate phase was extended to model the equilibrium SVOC concentrations in both the gas and particulate phases from the SVOC concentration measured in settled dust. This approach, based on the theory of SVOC partitioning among the gas phase, particulate phase, and settled dust incorporating Monte Carlo simulation, was validated using measured data from the literature and applied to the prediction of the concentrations of 48 SVOCs in both the gas and particulate phases in 3.6 million French dwellings where at least one child aged 6 months to 6 years lived. The median gas-phase concentration of 15 SVOCs, i.e., 5 phthalates, 2 organochlorine pesticides, 4 polycyclic aromatic hydrocarbons (PAHs), 2 synthetic musks, dichlorvos, and tributyl phosphate, was found to be higher than 1 ng/m³. The median concentration of 5 phthalates in the particulate phase was higher than 1 ng/m³. The impacts of some physical parameters, such as the molar mass and boiling point, on the SVOC partitioning among the different phases were quantified. The partitioning depends on the activity coefficient, vapor pressure at the boiling point, entropy of evaporation of the SVOCs, and the fraction of organic matter in particles. Thus, the partitioning may differ from one chemical family to another. The empirical equations based on regressions allow quick estimation of SVOC partitioning among the gas phase, particulate phase, and settled dust from the molar mass and boiling point.

Chemical-by-chemical and cumulative risk assessment of residential indoor exposure to semivolatile organic compounds in France

BACKGROUND

The toxic effects of environmental exposure to chemicals are increasingly being studied and confirmed, notably for semivolatile organic compounds (SVOCs). These are found in many products and housing materials, from which they are emitted to indoor air, settled dust and other surfaces.

OBJECTIVES

The objective of this work is to assess the human health risk posed by residential indoor exposure to 32 SVOCs, assessed in previous nationwide studies.

METHODS

A chemical-by-chemical risk assessment, using a hazard quotient (HQ) or excess risk (ER) method, was supplemented by a cumulative risk assessment (CRA). For CRA, a hazard index (HI) method, as well as higher tier approaches using relative potency factors (RPFs) or toxic equivalency factors (TEFs) were used for the following endpoints: neurotoxicity, reproductive toxicity, genotoxicity and immunotoxicity.

RESULTS

HQs were above 1 for 50% of French children from birth to 2 years for BDE 47, and for 5% of children for lindane and dibutyl phthalate (DBP). Corresponding hazards are reprotoxic for BDE 47 and DBP, and immunotoxic for lindane. The CRA approach provided additional information of reprotoxic risks (HI > 1) that may occur for 95% of children and for 5% of the offspring for pregnant women's exposure. The SVOCs contributing most to these risks were PCB 101 and 118, BDE 47, and DBP. The higher tier CRA approaches showed that exposure to dwellings' SVOC mixtures were of concern for 95% of children for neurotoxic compounds having effects linked with neuronal death. To a lesser extent, effects mediated by the aryl hydrocarbon receptor (AhR) or by a decrease in testosterone levels may concern 5% of children and adults. Lastly, unacceptable immunotoxic risk related to exposure to 8 indoor PCBs was also observed for 5% of children.

CONCLUSIONS

In view of uncertainties related to compounds' toxicity for humans, these results justify the implementation of preventive measures, as well as the production of more standardized and comprehensive toxicological data for some compounds.

[Occurrence of visible molds in French schools and nurseries]

Children exposure to molds in the school and preschool environment is not well described in France. A nationwide survey was performed in 2009-2011 in 310 schools and nurseries from France including two oversea territories, Reunion and Martinique. It showed that 5 % of the audited rooms had visible molds, mainly on the ceiling. These rooms belonged to 34 buildings (11 %). The multivariate analysis shows that several factors are associated with visible molds in rooms: the presence of textile wall covering, the location of the building in a suburban area, the size of the building (less visible molds in large buildings), the absence of a ventilation system with exhaust located in the room, and the absence of double-glazed windows. The prevalence of visible molds is comparable to the one observed in large European studies: 7 % of the 334 classrooms in the frame of the SINPHONIE project and 11 % of the buildings in 193 elementary schools in the HITEA study.

Oral bioaccessibility of semi-volatile organic compounds (SVOCs) in settled dust: A review of measurement methods, data and influencing factors

Many semi-volatile organic compounds (SVOCs), suspected of reprotoxic, neurotoxic or carcinogenic effects, were measured in indoor settled dust. Dust ingestion is a non-negligible pathway of exposure to some of these SVOCs, and an accurate knowledge of the real exposure is necessary for a better evaluation of health risks. To this end, the bioaccessibility of SVOCs in dust needs to be considered. In the present work, bioaccessibility measurement methods, SVOCs' oral bioaccessibility data and influencing factors were reviewed. SVOC bioaccessibilities (%) ranged from 11 to 94, 8 to 100, 3 to 92, 1 to 81, 6 to 52, and 2 to 17, for brominated flame retardants, organophosphorus flame retardants, polychlorobiphenyls, phthalates, pesticides and polycyclic aromatic hydrocarbons, respectively. Measurements method produced varying results depending on the inclusion of food and/or sink in the model. Characteristics of dust, e.g., organic matter content and particle size, also influenced bioaccessibility data. Last, results were influenced by SVOC properties, such as octanol/water partition coefficient and migration pathway into dust. Factors related to dust and SVOCs could be used in prediction models. To this end, more bioaccessibility studies covering more substances should be performed, using methods that are harmonized and validated by comparison to in-vivo studies.

Bioaccessibility and bioavailability of environmental semi-volatile organic compounds via inhalation: A review of methods and models

Semi-volatile organic compounds (SVOCs) present in indoor environments are known to cause adverse health effects through multiple routes of exposure. To assess the aggregate exposure, the bioaccessibility and bioavailability of SVOCs need to be determined. In this review, we discussed measurements of the bioaccessibility and bioavailability of SVOCs after inhalation. Published literature related to this issue is available for 2,3,7,8-tetrachlorodibenzo-p-dioxin and a few polycyclic aromatic hydrocarbons, such as benzo[a]pyrene and phenanthrene. Then, we reviewed common modeling approaches for the characterization of the gas- and particle-phase partitioning of SVOCs during inhalation. The models are based on mass transfer mechanisms as well as the structure of the respiratory system, using common computational techniques, such as computational fluid dynamics. However, the existing models are restricted to special conditions and cannot predict SVOC bioaccessibility and bioavailability in the whole respiratory system. The present review notes two main challenges for the estimation of SVOC bioaccessibility and bioavailability via inhalation in humans. First, in vitro and in vivo methods need to be developed and validated for a wide range of SVOCs. The in vitro methods should be validated with in vivo tests to evaluate human exposures to SVOCs in airborne particles. Second, modeling approaches for SVOCs need to consider the whole respiratory system. Alterations of the respiratory cycle period and human biological variability may be considered in future studies.

Influence of indoor environmental factors on mass transfer parameters and concentrations of semi-volatile organic compounds

Semi-volatile organic compounds (SVOCs) in indoor environments can partition among the gas phase, airborne particles, settled dust, and available surfaces. The mass transfer parameters of SVOCs, such as the mass transfer coefficient and the partition coefficient, are influenced by indoor environmental factors. Subsequently, indoor SVOC concentrations and thus occupant exposure can vary depending on environmental factors. In this review, the influence of six environmental factors, i.e., indoor temperature, humidity, ventilation, airborne particle concentration, source loading factor, and reactive chemistry, on the mass transfer parameters and indoor concentrations of SVOCs was analyzed and tentatively quantified. The results show that all mass transfer parameters vary depending on environmental factors. These variations are mostly characterized by empirical equations, particularly for humidity. Theoretical calculations of these parameters based on mass transfer mechanisms are available only for the emission of SVOCs from source surfaces when airborne particles are not present. All mass transfer parameters depend on the temperature. Humidity influences the partition of SVOCs among different phases and is associated with phthalate hydrolysis. Ventilation has a combined effect with the airborne particle concentration on SVOC emission and their mass transfer among different phases. Indoor chemical reactions can produce or eliminate SVOCs slowly. To better model the dynamic SVOC concentration indoors, the present review suggests studying the combined effect of environmental factors in real indoor environments. Moreover, interactions between indoor environmental factors and human activities and their influence on SVOC mass transfer processes should be considered.

Indoor air quality in energy-efficient dwellings: Levels and sources of pollutants

Worldwide, public policies are promoting energy-efficient buildings and accelerating the thermal renovation of existing buildings. The effects of these changes on the indoor air quality (IAQ) in these buildings remain insufficiently understood. In this context, a field study was conducted in 72 energy-efficient dwellings to describe the pollutants known to be associated with health concerns. Measured parameters included the concentrations of 19 volatile organic compounds and aldehydes, nitrogen dioxide, particulate matter (PM_2.5 ), radon, temperature, and relative humidity. The air stuffiness index and night-time air exchange rate were calculated from the monitored carbon dioxide (CO₂ ) concentrations. Indoor and outdoor measurements were performed at each dwelling during 1 week in each of the two following seasons: heating and non-heating. Moreover, questionnaires were completed by the occupants to characterize the building, equipment, household, and occupants' habits. Perspective on our results was provided by previous measurements made in low-energy European dwellings. Statistical comparisons with the French housing stock and a pilot study showed higher concentrations of terpenes, that is, alpha-pinene and limonene, and hexaldehyde in our study than in previous studies. Alpha-pinene and hexaldehyde are emitted by wood or wood-based products used for the construction, insulation, decoration, and furnishings of the dwellings, whereas limonene is more associated with discontinuous sources related to human activities.

Indoor residential exposure to semivolatile organic compounds in France

Multiple chemicals are emitted in residential accommodation. Aggregate Daily Doses (ADD) (ng/kg-bw/d) were estimated for 32 semivolatile organic compounds (SVOCs) of different chemical families that are frequently detected in French dwellings in both air and settled dust. Daily doses were determined using steady-state models for the population, categorized into 11 age groups covering birth to age 30. Three routes of exposure were taken into account: dust ingestion, inhalation (gaseous and particulate phases) and dermal contact with the gaseous phase of air. Contamination levels were preferentially retrieved from large, nationwide representative datasets. A two-dimensional probabilistic approach was used to assess parametric uncertainty and identify the most influential factors. For children aged 2 to 3years, ADD estimates spanned orders of magnitude, with median values ranging from 8.7pg/kg-bw/d for 2,2',3,4,4'-pentabromodiphenylether (BDE 85) to 1.3μg/kg-bw/d for di-isobutyl phthalate (DiBP). Inhalation, ingestion and dermal pathway contributed at varying levels, and depending on compound, air was the dominant medium for 28 of the 32 compounds (either by inhalation or dermal contact). Indoor exposure estimate variance was mainly driven by indoor contamination variability, and secondarily by uncertainty in physical and chemical parameters. These findings lend support to the call for cumulative risk assessment of indoor SVOCs.

Perceived indoor air quality and its relationship to air pollutants in French dwellings

Perception of indoor air quality (PIAQ) was evaluated in a nationwide survey of 567 French dwellings, and this survey was combined with measurements of gaseous and particulate matter (PM₁₀ and PM_2.5 ) indoor air pollutants and indoor climate parameters. The perception was assessed on a nine-grade scale by both the occupants of the dwellings and the inspectors who performed the measurements. The occupants perceived the air quality in their homes as more pleasant than the inspectors. The inspectors perceived the air quality as more unpleasant in dwellings in which the residents smoked indoors. Significant associations between PIAQ and indoor air pollutant concentrations were observed for both the inspectors and, to a lesser extent, the occupants. Introducing confounding parameters, such as building and personal characteristics, into a multivariate model suppressed most of the observed bivariate correlations and identified the tenure status of the occupants and their occupation as the parameters that most influenced their PIAQ. For the inspectors, perceived air quality was affected by the presence of smokers, the season, the type of ventilation, retrofitting, and the concentrations of acetaldehyde and acrolein.

Socio-economic costs of indoor air pollution: A tentative estimation for some pollutants of health interest in France

An evaluation of the socio-economic costs of indoor air pollution can facilitate the development of appropriate public policies. For the first time in France, such an evaluation was conducted for six selected pollutants: benzene, trichloroethylene, radon, carbon monoxide, particles (PM_2.5 fraction), and environmental tobacco smoke (ETS). The health impacts of indoor exposure were either already available in published works or were calculated. For these calculations, two approaches were followed depending on the available data: the first followed the principles of quantitative health risk assessment, and the second was based on concepts and methods related to the health impact assessment. For both approaches, toxicological data and indoor concentrations related to each target pollutant were used. External costs resulting from mortality, morbidity (life quality loss) and production losses attributable to these health impacts were assessed. In addition, the monetary costs for the public were determined. Indoor pollution associated with the selected pollutants was estimated to have cost approximately €20 billion in France in 2004. Particles contributed the most to the total cost (75%), followed by radon. Premature death and the costs of the quality of life loss accounted for approximately 90% of the total cost. Despite the use of different methods and data, similar evaluations previously conducted in other countries yielded figures within the same order of magnitude.

Spatial and temporal variation of particulate matter characteristics within office buildings - The OFFICAIR study

In the frame of the OFFICAIR project, office buildings were investigated across Europe to assess how the office workers are exposed to different particulate matter (PM) characteristics (i.e. PM_2.5 mass concentration, particulate oxidative potential (OP) based on ascorbate and reduced glutathione depletion, trace element concentration and total particle number concentration (PNC)) within the buildings. Two offices per building were investigated during the working hours (5 consecutive days; 8h per day) in two campaigns. Differences were observed for all parameters across the office buildings. Our results indicate that the monitoring of the PM_2.5 mass concentration in different offices within a building might not reflect the spatial variation of the health relevant PM characteristics such as particulate OP or the concentration of certain trace elements (e.g., Cu, Fe), since larger differences were apparent within a building for these parameters compared to that obtained for the PM_2.5 mass concentration in many cases. The temporal variation was larger for almost all PM characteristics (except for the concentration of Mn) than the spatial differences within the office buildings. These findings indicate that repeated or long-term monitoring campaigns are necessary to have information about the temporal variation of the PM characteristics. However, spatial variation in exposure levels within an office building may cause substantial differences in total exposure in the long term. We did not find strong associations between the investigated indoor activities such as printing or windows opening and the PNC values. This might be caused by the large number of factors affecting PNC indoors and outdoors.

Dermal absorption of semivolatile organic compounds from the gas phase: Sensitivity of exposure assessment by steady state modeling to key parameters

Recent research has demonstrated the importance of dermal exposure for some semivolatile organic compounds (SVOCs) present in the gas phase of indoor air. Though models for estimating dermal intake from gaseous SVOCs exist, their predictions can be subject to variations in input parameters, which can lead to large variation in exposure estimations. In this sensitivity analysis for a steady state model, we aimed to assess these variations and their determinants using probabilistic Monte Carlo sampling for 8 SVOCs from different chemical families: phthalates, bisphenols, polycyclic aromatic hydrocarbons (PAHs), organophosphorus (OPs), organochlorines (OCs), synthetic musks, polychlorinated biphenyls (PCBs) and polybromodiphenylethers (PBDEs). Indoor SVOC concentrations were found to be the most influential parameters. Both Henry's law constant (H) and octanol/water partition coefficient (K_ow) uncertainty also had significant influence. While exposure media properties such as volume fraction of organic matter in the particle phase (f_om-part), particle density (ρ_part), concentration ([TSP]) and transport coefficient (ɣ_d) had a slight influence for some compounds, human parameters such as body weight (W), body surface area (A) and daily exposure (t) make a marginal or null contribution to the variance of dermal intake for a given age group. Inclusion of a parameter sensitivity analysis appears essential to reporting uncertainties in dermal exposure assessment.

Assessment of indoor air quality in office buildings across Europe - The OFFICAIR study

The European project OFFICAIR aimed to broaden the existing knowledge regarding indoor air quality (IAQ) in modern office buildings, i.e., recently built or refurbished buildings. Thirty-seven office buildings participated in the summer campaign (2012), and thirty-five participated in the winter campaign (2012-2013). Four rooms were investigated per building. The target pollutants were twelve volatile organic compounds, seven aldehydes, ozone, nitrogen dioxide and particulate matter with aerodynamic diameter <2.5μm (PM_2.5). Compared to other studies in office buildings, the benzene, toluene, ethylbenzene, and xylene concentrations were lower in OFFICAIR buildings, while the α-pinene and d-limonene concentrations were higher, and the aldehyde, nitrogen dioxide and PM_2.5 concentrations were of the same order of magnitude. When comparing summer and winter, significantly higher concentrations were measured in summer for formaldehyde and ozone, and in winter for benzene, α-pinene, d-limonene, and nitrogen dioxide. The terpene and 2-ethylhexanol concentrations showed heterogeneity within buildings regardless of the season. Considering the average of the summer and winter concentrations, the acetaldehyde and hexanal concentrations tended to increase by 4-5% on average with every floor level increase, and the nitrogen dioxide concentration tended to decrease by 3% on average with every floor level increase. A preliminary evaluation of IAQ in terms of potential irritative and respiratory health effects was performed. The 5-day median and maximum indoor air concentrations of formaldehyde and ozone did not exceed their respective WHO air quality guidelines, and those of acrolein, α-pinene, and d-limonene were lower than their estimated thresholds for irritative and respiratory effects. PM_2.5 indoor concentrations were higher than the 24-h and annual WHO ambient air quality guidelines.

A first overview of textile fibers, including microplastics, in indoor and outdoor environments

Studies about microplastics in various environments highlighted the ubiquity of anthropogenic fibers. As a follow-up of a recent study that emphasized the presence of man-made fibers in atmospheric fallout, this study is the first one to investigate fibers in indoor and outdoor air. Three different indoor sites were considered: two private apartments and one office. In parallel, the outdoor air was sampled in one site. The deposition rate of the fibers and their concentration in settled dust collected from vacuum cleaner bags were also estimated. Overall, indoor concentrations ranged between 1.0 and 60.0 fibers/m³. Outdoor concentrations are significantly lower as they range between 0.3 and 1.5 fibers/m³. The deposition rate of the fibers in indoor environments is between 1586 and 11,130 fibers/day/m² leading to an accumulation of fibers in settled dust (190-670 fibers/mg). Regarding fiber type, 67% of the analyzed fibers in indoor environments are made of natural material, primarily cellulosic, while the remaining 33% fibers contain petrochemicals with polypropylene being predominant. Such fibers are observed in marine and continental studies dealing with microplastics. The observed fibers are supposedly too large to be inhaled but the exposure may occur through dust ingestion, particularly for young children.

Predicting the gas-phase concentration of semi-volatile organic compounds from airborne particles: Application to a French nationwide survey

Semi-volatile organic compounds (SVOCs) partition indoors between the gas phase, airborne particles, settled dust, and other surfaces. Unknown concentrations of SVOCs in the gas phase (C_g) can be predicted from their measured concentrations in airborne particles. In previous studies, the prediction of C_g depended largely on choosing a specific equation for the calculation of the particle/gas partition coefficient. Moreover, the prediction of C_g is frequently performed at a reference temperature rather than the real indoor temperature. In this paper, a probabilistic approach based on Monte Carlo simulation was developed to predict the distribution of SVOCs' C_g from their concentrations in airborne particles at the target indoor temperature. Moreover, the distribution of the particle/gas partition coefficient of each SVOC at the target temperature was used. The approach was validated using two measured datasets in the literature: the predicted C_g from concentrations measured in airborne particles and the measured C_g were generally of the same order of magnitude. The distributions of the C_g of 66 SVOCs in the French housing stock were then predicted. The SVOCs with the highest median C_g, ranging from 1ng/m³ to >100ng/m³, included 8 phthalates (DEP, DiBP, DBP, DEHP, BBP, DMP, DiNP, and DMEP), 4 polycyclic aromatic hydrocarbons (fluorene, phenanthrene, fluoranthene, and anthracene), 2 alkylphenols (4-tert-butylphenol and 4-tert-octylphenol), 2 synthetic musks (galaxolide and tonalide), tributyl phosphate, and heptachlor. The nationwide, representative, predicted C_g values of SVOCs are frequently of the same order of magnitude in Europe and North America, whereas these C_g values in Chinese and Indian dwellings and the C_g of polybrominated diphenyl ethers in U.S. dwellings are generally higher.

Relationships between indoor radon concentrations, thermal retrofit and dwelling characteristics

A monitoring campaign was conducted on a sample of more than 3400 dwellings in Brittany, France from 2011 to 2014. The measurements were collected using one passive dosimeter per dwelling over two months during the heating season, according to the NF ISO 11665-8 (2013) standard. Moreover, building characteristics such as the period of construction, construction material, type of foundation, and thermal retrofit were determined using a questionnaire. The final data set consisted of 3233 houses with the measurement results and the questionnaire answers. Multivariate linear regression models were applied to explore the relationships between the indoor radon concentrations and building characteristics, particularly the thermal retrofit. The geometric mean of the indoor radon concentration was 155 Bq m^-3 (with a geometric standard deviation of 3). The houses that had undergone a thermal retrofit had a higher average radon concentration than those that had not, which may have been due to a decrease in air permeability of the building envelope following rehabilitation work that did not systematically include proper management of the ventilation. Other building characteristics, primarily the building material and the foundation type, were associated with the indoor radon concentration. The indoor radon concentrations were higher in older houses built with granite or other stone, with a slab-on-grade foundation and without any ventilation system.

Temperature dependence of the particle/gas partition coefficient: An application to predict indoor gas-phase concentrations of semi-volatile organic compounds

The indoor gas-phase concentrations of semi-volatile organic compounds (SVOCs) can be predicted from their respective concentrations in airborne particles by applying the particle/gas partitioning equilibrium. The temperature used for partitioning is often set to 25°C. However, indoor temperatures frequently differ from this reference value. This assumption may result in errors in the predicted equilibrium gas-phase SVOC concentrations. To improve the prediction model, the temperature dependence of the particle/gas partition coefficient must be addressed. In this paper, a theoretical relationship between the particle/gas partition coefficient and temperature was developed based on the SVOC absorptive mechanism. The SVOC particle/gas partition coefficients predicted by employing the derived theoretical relationship agree well with the experimental data retrieved from the literature (R>0.93). The influence of temperature on the equilibrium gas-phase SVOC concentration was quantified by a dimensionless analysis of the derived relationship between the SVOC particle/gas partition coefficient and temperature. The predicted equilibrium gas-phase SVOC concentration decreased by between 31% and 53% when the temperature was lowered by 6°C, while it increased by up to 750% when the indoor temperature increased from 15°C to 30°C.

Cleaning practices and cleaning products in nurseries and schools: to what extent can they impact indoor air quality?

In the framework of a nationwide survey on indoor air quality conducted from September 2009 to June 2011 in 310 nurseries, kindergartens, and elementary schools in all regions of France, cleaning practices and products were described through an extensive questionnaire completed on-site by expert building inspectors. The questionnaire included the cleaning frequencies and periods, cleaning techniques, whether windows were open during cleaning, and the commercial names of the products used. Analysis of the questionnaire responses showed that cleaning was generally performed daily for furniture and floors. It was performed mostly in the evening with wet mopping and with one or more windows open. Five hundred eighty-four different cleaning products were listed, among which 218 safety data sheets (SDSs) were available and analyzed. One hundred fifty-two chemical substances were identified in the SDSs. The typical substances in cleaning products included alcohols, chlorides, terpenes, aldehydes, and ethers; more than half of them are irritants. Two endocrine disruptors, 2-phenylphenol and Galaxolide, were identified in two cleaning products used every day to clean the floors, in seven kindergartens and in a nursery respectively. Eleven reactive substances containing C=C double bonds, mostly terpenes, were identified in a wide variety of cleaning products.

Oxidative potential and chemical composition of PM2.5 in office buildings across Europe - The OFFICAIR study

In the frame of the OFFICAIR project, indoor and outdoor PM2.5 samples were collected in office buildings across Europe in two sampling campaigns (summer and winter). The ability of the particles to deplete physiologically relevant antioxidants (ascorbic acid (AA), reduced glutathione (GSH)) in a synthetic respiratory tract lining fluid, i.e., oxidative potential (OP), was assessed. Furthermore, the link between particulate OP and the concentration of the PM constituents was investigated. The mean indoor PM2.5 mass concentration values were substantially lower than the related outdoor values with a mean indoor/outdoor PM2.5 mass concentration ratio of 0.62 and 0.61 for the summer and winter campaigns respectively. The OP of PM2.5 varied markedly across Europe with the highest outdoor OP(AA) m(-3) and OP(GSH) m(-3) (% antioxidant depletion/m(3) air) values obtained for Hungary, while PM2.5 collected in Finland exhibited the lowest values. Seasonal variation could be observed for both indoor and outdoor OP(AA) m(-3) and OP(GSH) m(-3) with higher mean values during winter. The indoor/outdoor OP(AA) m(-3) and OP(GSH) m(-3) ratios were less than one with 4 and 17 exceptions out of the 40 cases respectively. These results indicate that indoor air is generally less oxidatively challenging than outdoors. Correlation analysis revealed that trace elements play an important role in determining OP, in particular, the Cu content. Indoor air chemistry might affect OP since weaker correlations were obtained for indoor PM2.5. Our findings also suggest that office workers may be exposed to health relevant PM constituents to a different extent within the same building.

Distributions of the particle/gas and dust/gas partition coefficients for seventy-two semi-volatile organic compounds in indoor environment

Particle/gas and dust/gas partition coefficients (Kp and Kd) are two key parameters that address the partitioning of semi-volatile organic compounds (SVOCs) between gas-phase, airborne particles, and settled dust in indoor environment. A number of empirical equations to calculate the values of Kp and Kd have been reported in the literature. Therefore, the difficulty lies in the selection of a specific empirical equation in a given situation. In this study, we retrieved from the literature 38 empirical equations for calculating Kp and Kd values from the SVOC saturation vapor pressure and octanol/air partition coefficient. These values were calculated for 72 SVOCs: 9 phthalates, 9 polybrominated diphenyl ethers (PBDEs), 11 polychlorinated biphenyls (PCBs), 22 biocides, 14 polycyclic aromatic hydrocarbons (PAHs), 3 alkylphenols, 2 synthetic musks, tributylphosphate, and bisphenol A. The mean and median values of log10Kp or log10Kd for most SVOCs were of the same order of magnitude. The distribution of log10Kp values was fitted to either a normal distribution (for 27 SVOCs) or a log-normal distribution (for 45 SVOCs). This work provides a reference distribution of the log10Kp for 72 SVOCs, and its use may reduce the bias associated with the selection of a specific value or equation.

Assessment of ventilation and indoor air pollutants in nursery and elementary schools in France

The aim of this study was to characterize the relationship between Indoor Air Quality (IAQ) and ventilation in French classrooms. Various parameters were measured over one school week, including volatile organic compounds, aldehydes, particulate matter (PM2.5 mass concentration and number concentration), carbon dioxide (CO2 ), air temperature, and relative humidity in 51 classrooms at 17 schools. The ventilation was characterized by several indicators, such as the air exchange rate, ventilation rate (VR), and air stuffiness index (ICONE), that are linked to indoor CO2 concentration. The influences of the season (heating or non-heating), type of school (nursery or elementary), and ventilation on the IAQ were studied. Based on the minimum value of 4.2 l/s per person required by the French legislation for mechanically ventilated classrooms, 91% of the classrooms had insufficient ventilation. The VR was significantly higher in mechanically ventilated classrooms compared with naturally ventilated rooms. The correlations between IAQ and ventilation vary according to the location of the primary source of each pollutant (outdoor vs. indoor), and for an indoor source, whether it is associated with occupant activity or continuous emission.

Perceived Indoor Environment and Occupants' Comfort in European "Modern" Office Buildings: The OFFICAIR Study

Indoor environmental conditions (thermal, noise, light, and indoor air quality) may affect workers' comfort, and consequently their health and well-being, as well as their productivity. This study aimed to assess the relations between perceived indoor environment and occupants' comfort, and to examine the modifying effects of both personal and building characteristics. Within the framework of the European project OFFICAIR, a questionnaire survey was administered to 7441 workers in 167 "modern" office buildings in eight European countries (Finland, France, Greece, Hungary, Italy, The Netherlands, Portugal, and Spain). Occupants assessed indoor environmental quality (IEQ) using both crude IEQ items (satisfaction with thermal comfort, noise, light, and indoor air quality), and detailed items related to indoor environmental parameters (e.g., too hot/cold temperature, humid/dry air, noise inside/outside, natural/artificial light, odor) of their office environment. Ordinal logistic regression analyses were performed to assess the relations between perceived IEQ and occupants' comfort. The highest association with occupants' overall comfort was found for "noise", followed by "air quality", "light" and "thermal" satisfaction. Analysis of detailed parameters revealed that "noise inside the buildings" was highly associated with occupants' overall comfort. "Layout of the offices" was the next parameter highly associated with overall comfort. The relations between IEQ and comfort differed by personal characteristics (gender, age, and the Effort Reward Imbalance index), and building characteristics (office type and building's location). Workplace design should take into account both occupant and the building characteristics in order to provide healthier and more comfortable conditions to their occupants.

Self-reported health and comfort in 'modern' office buildings: first results from the European OFFICAIR study

In the European research project OFFICAIR, a procedure was developed to determine associations between characteristics of European offices and health and comfort of office workers, through a checklist and a self-administered questionnaire including environmental, physiological, psychological, and social aspects. This procedure was applied in 167 office buildings in eight European countries (Portugal, Spain, Italy, Greece, France, Hungary, the Netherlands, and Finland) during the winter of 2011-2012. About 26 735 survey invitation e-mails were sent, and 7441 office workers were included in the survey. Among respondents who rated an overall comfort less than 4 (23%), 'noise (other than from building systems)', air 'too dry', and temperature 'too variable' were the main complaints selected. An increase of perceived control over indoor climate was positively associated with the perceived indoor environment quality. Almost one-third of office workers suffered from dry eyes and headache in the last 4 weeks. Physical building characteristics were associated with occupants' overall satisfaction (acoustical solutions, mold growth, complaints procedure, cleaning activities) and health (number of occupants, lack of operable windows, presence of carpet and cleaning activities). OFFICAIR project provides a useful database to identify stressors related to indoor environmental quality and office worker's health.

Endocrine disrupting compounds in gaseous and particulate outdoor air phases according to environmental factors

This study investigated, for the first time in France, the spatial and temporal patterns of 55 endocrine disrupting chemicals (EDCs) in ambient air at three sites (urban, suburban and forest) under two climatic periods (warm/cold) for 2 successive years. All EDCs, except tetrabromobisphenol A (TBBPA), were encountered with various frequencies of up to 100%. Phthalate diesters (PAEs) were the most abundant chemicals with total concentrations as the sum of compounds, ranging from 10 to 100 ng m(-3) of total air, followed by alkylphenols (APs) and polycyclic aromatic hydrocarbons (PAHs), which were both approximately 1 ng m(-3). Polychlorinated biphenyl (PCBs) and bisphenol A (BPA) concentrations were notably lower (approximately 0.1 ng m(-3)). Air concentrations, depending on the considered compounds, were from 1.2 to 2 times higher in the urban than the suburban area and from 2 to 5 times higher in the urban than the forest site. PAH emissions were higher in the cold period, due to combustion processes. This finding is contrary to the other EDCs that are more abundant in the summer and governed by volatilisation. Most of the EDCs were largely distributed in the gaseous phase (>80% in the summer). The octanol/air partition coefficient (KOA) and vapour pressure (Vp) were relevant parameters for predicting EDC partitioning and direct relationships (p < 0.001) were observed i) between log K particle/gas partitioning (log Kp) and log KOA and ii) between EDC ratios in the gaseous phase and log vapour pressure (log Vp).

Relationships between socioeconomic and lifestyle factors and indoor air quality in French dwellings

BACKGROUND

To date, few studies have analyzed the relationships between socioeconomic status (SES) and indoor air quality (IAQ).

OBJECTIVE

The aim of this study was to examine the relationships between socioeconomic and other factors and indoor air pollutant levels in French homes.

METHODS

The indoor air concentrations of thirty chemical, biological and physical parameters were measured over one week in a sample of 567 dwellings representative of the French housing stock between September 2003 and December 2005. Information on SES (household structure, educational attainment, income, and occupation), building characteristics, and occupants' habits and activities (smoking, cooking, cleaning, etc.) were collected through administered questionnaires. Separate stepwise linear regression models were fitted to log-transformed concentrations on SES and other factors. Logistic regression was performed on fungal contamination data.

RESULTS

Households with lower income were more likely to have higher indoor concentrations of formaldehyde, but lower perchloroethylene indoor concentrations. Formaldehyde indoor concentrations were also associated with newly built buildings. Smoking was associated with increasing acetaldehyde and PM2.5 levels and the risk of a positive fungal contamination index. BTEX levels were also associated with occupant density and having an attached garage. The major predictors for fungal contamination were dampness and absolute humidity.

CONCLUSION

These results, obtained from a large sample of dwellings, show for the first time in France the relationships between SES factors and indoor air pollutants, and believe they should be considered alongside occupant activities and building characteristics when study IAQ in homes.

Relationships between socioeconomic and lifestyle factors and indoor air quality in French dwellings

BACKGROUND

To date, few studies have analyzed the relationships between socioeconomic status (SES) and indoor air quality (IAQ).

OBJECTIVE

The aim of this study was to examine the relationships between socioeconomic and other factors and indoor air pollutant levels in French homes.

METHODS

The indoor air concentrations of thirty chemical, biological and physical parameters were measured over one week in a sample of 567 dwellings representative of the French housing stock between September 2003 and December 2005. Information on SES (household structure, educational attainment, income, and occupation), building characteristics, and occupants' habits and activities (smoking, cooking, cleaning, etc.) were collected through administered questionnaires. Separate stepwise linear regression models were fitted to log-transformed concentrations on SES and other factors. Logistic regression was performed on fungal contamination data.

RESULTS

Households with lower income were more likely to have higher indoor concentrations of formaldehyde, but lower perchloroethylene indoor concentrations. Formaldehyde indoor concentrations were also associated with newly built buildings. Smoking was associated with increasing acetaldehyde and PM2.5 levels and the risk of a positive fungal contamination index. BTEX levels were also associated with occupant density and having an attached garage. The major predictors for fungal contamination were dampness and absolute humidity.

CONCLUSION

These results, obtained from a large sample of dwellings, show for the first time in France the relationships between SES factors and indoor air pollutants, and believe they should be considered alongside occupant activities and building characteristics when study IAQ in homes.

Ozone-initiated terpene reaction products in five European offices: replacement of a floor cleaning agent

Cleaning agents often emit terpenes that react rapidly with ozone. These ozone-initiated reactions, which occur in the gas-phase and on surfaces, produce a host of gaseous and particulate oxygenated compounds with possible adverse health effects in the eyes and airways. Within the European Union (EU) project OFFICAIR, common ozone-initiated reaction products were measured before and after the replacement of the regular floor cleaning agent with a preselected low emitting floor cleaning agent in four offices located in four EU countries. One reference office in a fifth country did not use any floor cleaning agent. Limonene, α-pinene, 3-carene, dihydromyrcenol, geraniol, linalool, and α-terpineol were targeted for measurement together with the common terpene oxidation products formaldehyde, 4-acetyl-1-methylcyclohexene (4-AMCH), 3-isopropenyl-6-oxo-heptanal (IPOH), 6-methyl-5-heptene-2-one, (6-MHO), 4-oxopentanal (4-OPA), and dihydrocarvone (DHC). Two-hour air samples on Tenax TA and DNPH cartridges were taken in the morning, noon, and in the afternoon and analyzed by thermal desorption combined with gas chromatography/mass spectrometry and HPLC/UV analysis, respectively. Ozone was measured in all sites. All the regular cleaning agents emitted terpenes, mainly limonene and linalool. After the replacement of the cleaning agent, substantially lower concentrations of limonene and formaldehyde were observed. Some of the oxidation product concentrations, in particular that of 4-OPA, were also reduced in line with limonene. Maximum 2 h averaged concentrations of formaldehyde, 4-AMCH, 6-MHO, and IPOH would not give rise to acute eye irritation-related symptoms in office workers; similarly, 6-AMCH, DHC and 4-OPA would not result in airflow limitation to the airways.