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 (PM2.5 ), 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.

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.

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.