Applicability and relevance of six indoor air quality indexes

International audienceThe evaluation of indoor air quality (IAQ) in buildings is complex because IAQ involves a broad spectrum of substances and agents that vary over time and space. To address this complexity, IAQ indexes are used to describe, classify and improve IAQ by providing easy-to-understand and comprehensive rankings of IAQ levels in buildings. Although many IAQ indexes have been proposed all over the world, their relevancy regarding the evaluation of IAQ levels has not been fully studied in a large number of dwellings. In this study, six measurement-based IAQ indexes proposed for use in the USA, France, Taiwan, and Hong Kong were evaluated. The calculation of IAQ levels was based on nine indoor parameters measured in 567 French dwellings, i.e., indoor air temperature, relative humidity, and concentrations of formaldehyde, total volatile organic compounds, radon, carbon monoxide, carbon dioxide, PM2.5, and PM10. A factorial analysis using the multiple correspondence analysis and the hierarchical cluster analysis methods was performed to determine whether the calculated IAQ levels of different indexes in the studied dwellings were repeatable across all indexes. The results showed that three of the indexes tended to provide only positive IAQ ratings, while the other three indexes were more discriminating. Three classes of IAQ levels in dwellings, along with indoor parameters associated with each class, were identified. All of the indoor parameters were associated with the classification of IAQ 2 levels, while the formaldehyde concentration and relative humidity were the key parameters to identify the dwellings with the best IAQ

Base de référence nationale sur la qualité de l'air intérieur et le confort des occupants de bâtiments performants en énergie : deuxième état descriptif de la qualité de l'air intérieur et du confort de bâtiments d'habitation performants en énergie

Ce travail, réalisé dans le cadre de la convention 2014-2015 du programme "Bâtiments Performants en Énergie" de l'OQAI, fournit un deuxième état descriptif des données de qualité de l'environnement intérieur de bâtiments d'habitation performants en énergie. Il porte sur les données d'enquête relatives à 72 logements répartis dans 43 bâtiments. Le rapport, structuré en trois parties, présente : 1 /les caractéristiques des bâtiments, des logements et de leurs occupants ; 2 /les résultats des mesures de concentration du CO2, des indicateurs de qualité d'air intérieur, des paramètres de confort thermique et des débits/pressions aux bouches des systèmes de ventilation mécanique ainsi que la mise en perspective de ces résultats avec la population nationale de logements et les réglementations en vigueur non spécifiques à l'habitat ; 3/ les résultats d'une étude exploratoire sur l'influence de trois variables d'intérêt liées au bâtiment (pièce de mesure, type d'habitat et catégorie de logement) sur la qualité de l'environnement intérieur. Cette deuxième exploitation des données de la base nationale OQAI-BPE confirme les premières tendances observées lors de la première étude, à savoir une qualité de l'air intérieur globalement comparable dans les logements performants en énergie étudiés par rapport à la population nationale de logements, avec néanmoins quelques différences mises en évidence. Ainsi, dans les logements performants en énergie, on observe un indice de contamination fongique plus élevé en proportion, des concentrations en hexaldéhyde, alpha-pinène et limonène plus élevées, et des températures intérieures plus élevées. La suite de l'exploitation de la base OQAI-BPE vise à l'analyse approfondie des données de mesures en fonction des caractéristiques des bâtiments et de leurs occupants

Observatoire de la qualité de l'air intérieur : actions et résultats

National audienc

Kerosene space heaters: a major source of ultrafine particles indoors

Kerosene heaters are known to emit pollutants in the indoor environment but ultrafine particle emission was never reported. A kerosene heater was characterized in an experimental chamber using four different instruments to monitor particle number concentration and size distribution down to 5 nm. Another experiment was realized to collect particles and determine their composition in elements, ions, organic/elemental carbon and polycyclic aromatic hydrocarbons. The kerosene heater produced ultrafine particles in the range 5 to 40 nm with a count median diameter of 9.5 nm. The emission rate was (1.8±0.3)×1011 particle*s-1. Chromium and manganese (4 and 0.05 ng*g-1 of burned fuel) were specifically associated with kerosene combustion. Trace levels of sulfates, nitrates, phenanthrene and fluoranthene were also detected. Scanning electron microscopy showed submicronic aggregates mostly composed of carbon and traces of silicon. Our findings showed that kerosene heaters represent a major indoor source of ultrafine particles

Améliorer la qualité de l'air dans les écoles

National audienc

Kerosene space heaters: a major source of ultrafine particles indoors

Kerosene heaters are known to emit pollutants in the indoor environment but ultrafine particle emission was never reported. A kerosene heater was characterized in an experimental chamber using four different instruments to monitor particle number concentration and size distribution down to 5 nm. Another experiment was realized to collect particles and determine their composition in elements, ions, organic/elemental carbon and polycyclic aromatic hydrocarbons. The kerosene heater produced ultrafine particles in the range 5 to 40 nm with a count median diameter of 9.5 nm. The emission rate was (1.8±0.3)×1011 particle*s-1. Chromium and manganese (4 and 0.05 ng*g-1 of burned fuel) were specifically associated with kerosene combustion. Trace levels of sulfates, nitrates, phenanthrene and fluoranthene were also detected. Scanning electron microscopy showed submicronic aggregates mostly composed of carbon and traces of silicon. Our findings showed that kerosene heaters represent a major indoor source of ultrafine particles

Exposure Assessment of Allergens and Metals in Settled Dust in French Nursery and Elementary Schools

The aim of this study was to characterise the contamination in settled dust in French classrooms and to provide an overview of the influencing factors of dust contamination. Cat, dog and dust mite allergens and metals were measured in 51 classrooms at 17 schools. The concentrations of pet allergens in settled dust were generally low (mean value of 0.1 µg·g−1), with carpeted and rug-covered floors presenting higher dust and cat allergen concentrations. The highest metal loadings in dust were observed for manganese (Mn) and copper (Cu), while the lead (Pb) loadings were lower (16 ± 19 µg·m−2) and fell below the French guideline. Higher metal leachability was found for cadmium (Cd), Cu, Pb and strontium (Sr) at values of approximately 80%, which suggest that, in cases of dust ingestion by children, a large proportion should be assimilated through the gastro-intestinal tract. The intra-classroom and intra-school variabilities of the metal concentrations in settled dust were lower than the variability between schools. Classrooms with tiled floors had higher Pb loadings than classrooms with wood or vinyl floors. In addition, wet cleaning less than once a week resulted in greater loadings of Cu and Pb in the settled dust. Lastly, enrichment factors showed that metals in settled dust of classrooms were not only from the contribution of the natural background concentrations in soils

Base de référence nationale sur la qualité de l'air intérieur et le confort des occupants de bâtiments performants en énergie : deuxième état descriptif de la qualité de l'air intérieur et du confort de bâtiments d'habitation performants en énergie

Ce travail, réalisé dans le cadre de la convention 2014-2015 du programme "Bâtiments Performants en Énergie" de l'OQAI, fournit un deuxième état descriptif des données de qualité de l'environnement intérieur de bâtiments d'habitation performants en énergie. Il porte sur les données d'enquête relatives à 72 logements répartis dans 43 bâtiments. Le rapport, structuré en trois parties, présente : 1 /les caractéristiques des bâtiments, des logements et de leurs occupants ; 2 /les résultats des mesures de concentration du CO2, des indicateurs de qualité d'air intérieur, des paramètres de confort thermique et des débits/pressions aux bouches des systèmes de ventilation mécanique ainsi que la mise en perspective de ces résultats avec la population nationale de logements et les réglementations en vigueur non spécifiques à l'habitat ; 3/ les résultats d'une étude exploratoire sur l'influence de trois variables d'intérêt liées au bâtiment (pièce de mesure, type d'habitat et catégorie de logement) sur la qualité de l'environnement intérieur. Cette deuxième exploitation des données de la base nationale OQAI-BPE confirme les premières tendances observées lors de la première étude, à savoir une qualité de l'air intérieur globalement comparable dans les logements performants en énergie étudiés par rapport à la population nationale de logements, avec néanmoins quelques différences mises en évidence. Ainsi, dans les logements performants en énergie, on observe un indice de contamination fongique plus élevé en proportion, des concentrations en hexaldéhyde, alpha-pinène et limonène plus élevées, et des températures intérieures plus élevées. La suite de l'exploitation de la base OQAI-BPE vise à l'analyse approfondie des données de mesures en fonction des caractéristiques des bâtiments et de leurs occupants

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

International audienceThe 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

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

International audienceThe 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