• Energy Research

This study surveyed the indoor environment in Danish classrooms and explored its associations with pupil well-being and performance. It was a large-scale citizen science study using a simple intervention carried out over two days. On one of these days, the participating classes carefully aired out the classroom during the break before a lesson dedicated to measuring the classroom environment. They did this by keeping windows open and leaving the classroom during the break. On the other day, they were told to do as they usually do, i.e. they received no instruction to follow a particular airing behaviour. The order of the two airing behaviours was randomly balanced between classes. Measurements were reported by 709 classes in 234 schools and 640 classes completed a building checklist. In total, 21,326 well-being surveys and 20,701 concentration tests were completed by the pupils. Of these, a gross subsample of 13,094 records qualified for further analysis. With the instructed airing behaviour, the percentage of classes with a CO2 concentration higher than 1000 ppm was reduced from 53% to 36% as compared with uninstructed behaviour. This finding corresponded with earlier related studies carried out in Danish classrooms in 2014 and 2009. Airing also improved the pupils' perception of the classroom environment, alleviated their building-related symptoms and increased their performance of a concentration test in which they made 6% fewer errors than with uninstructed behaviour. Based on responses from a large number of pupils, the findings confirm that inadequate classroom ventilation negatively affects pupil well-being and concentration and that classroom air quality continues to present a challenge in many Danish school buildings.

This study surveyed the indoor environment in Danish classrooms and explored its associations with pupil well-being and performance. It was a large-scale citizen science study using a simple intervention carried out over two days. On one of these days, the participating classes carefully aired out the classroom during the break before a lesson dedicated to measuring the classroom environment. They did this by keeping windows open and leaving the classroom during the break. On the other day, they were told to do as they usually do, i.e. they received no instruction to follow a particular airing behaviour. The order of the two airing behaviours was randomly balanced between classes. Measurements were reported by 709 classes in 234 schools and 640 classes completed a building checklist. In total, 21,326 well-being surveys and 20,701 concentration tests were completed by the pupils. Of these, a gross subsample of 13,094 records qualified for further analysis. With the instructed airing behaviour, the percentage of classes with a CO2 concentration higher than 1000 ppm was reduced from 53% to 36% as compared with uninstructed behaviour. This finding corresponded with earlier related studies carried out in Danish classrooms in 2014 and 2009. Airing also improved the pupils' perception of the classroom environment, alleviated their building-related symptoms and increased their performance of a concentration test in which they made 6% fewer errors than with uninstructed behaviour. Based on responses from a large number of pupils, the findings confirm that inadequate classroom ventilation negatively affects pupil well-being and concentration and that classroom air quality continues to present a challenge in many Danish school buildings.

A European project started at the end of 1992, in which, in addition to current methods, trained sensory panels were used to investigate office buildings all over Europe. The main aim of this EC-Audit was to develop assessment procedures and guid-ance on ventilation and source control, to help optimize energy use in buildings while assuring good indoor air quality. In each of nine countries, six or more office buildings were select-ed. Measurements were performed at five selected locations in each building. The buildings were studied while normally occu-pied and ventilated to identify the pollution sources in the spaces and to quantify the total pollution load caused by the occupants and their activities, as well as the ventilation systems. The investi-gation included physical and chemical measurements, assessment of the perceived air quality in the spaces by a trained sensory pan-el, and measurement of the outdoor air supply to the spaces. A questionnaire for evaluating retrospective and immediate symp-toms and perceptions was given to the occupants of the buildings. The building characteristics were described by use of a check-list. The annual energy consumption of the buildings and the weather conditions were registered. This paper presents results and conclusions of the audit in 56 buildings in Europe. However, the analysis and discussions of the results are a summary of the work done, and are focused mainly on comparison between sensory assessments and the other meas-urements performed. Furthermore, this paper brings the results of the study based on a two-factor analysis. A paper dealing with results on a multifacto-rial analysis is in preparation.

A European project started at the end of 1992, in which, in addition to current methods, trained sensory panels were used to investigate office buildings all over Europe. The main aim of this EC-Audit was to develop assessment procedures and guid-ance on ventilation and source control, to help optimize energy use in buildings while assuring good indoor air quality. In each of nine countries, six or more office buildings were select-ed. Measurements were performed at five selected locations in each building. The buildings were studied while normally occu-pied and ventilated to identify the pollution sources in the spaces and to quantify the total pollution load caused by the occupants and their activities, as well as the ventilation systems. The investi-gation included physical and chemical measurements, assessment of the perceived air quality in the spaces by a trained sensory pan-el, and measurement of the outdoor air supply to the spaces. A questionnaire for evaluating retrospective and immediate symp-toms and perceptions was given to the occupants of the buildings. The building characteristics were described by use of a check-list. The annual energy consumption of the buildings and the weather conditions were registered. This paper presents results and conclusions of the audit in 56 buildings in Europe. However, the analysis and discussions of the results are a summary of the work done, and are focused mainly on comparison between sensory assessments and the other meas-urements performed. Furthermore, this paper brings the results of the study based on a two-factor analysis. A paper dealing with results on a multifacto-rial analysis is in preparation.

Abstract A simplified modelling framework for the prediction of the indoor environment, energy use and socio-economic consequences of improving air quality and temperature in school buildings is suggested. The framework combines established models for infiltration and different modes of ventilation to estimate yearly distributions of the classroom temperature and CO2 concentration. These distributions are used as input to a prediction of pupil performance of schoolwork, their attendance at school, and teacher absence before and after refurbishment of their school building. Eventually, the framework estimates the socio-economic consequences of an improved classroom environment for a school and may be used to evaluate the feasibility of a range of different refurbishment scenarios and support decisions on building upgrades.

Abstract A simplified modelling framework for the prediction of the indoor environment, energy use and socio-economic consequences of improving air quality and temperature in school buildings is suggested. The framework combines established models for infiltration and different modes of ventilation to estimate yearly distributions of the classroom temperature and CO2 concentration. These distributions are used as input to a prediction of pupil performance of schoolwork, their attendance at school, and teacher absence before and after refurbishment of their school building. Eventually, the framework estimates the socio-economic consequences of an improved classroom environment for a school and may be used to evaluate the feasibility of a range of different refurbishment scenarios and support decisions on building upgrades.

Abstract Air quality was studied in an office space classified as low-polluting and ventilated with outdoor air at a rate of 1 h−1. The pollution load in the space was changed by introducing or removing common building-related indoor pollution sources (linoleum, sealant and wooden shelves with books and paper documents) so that the space could no longer be classified as low-polluting. The outdoor air supply rate in the office was altered from 1 to 3 h−1 (0.83 and 2.5 l/s per m2 floor, respectively) when sources were present and absent. Air temperature of 23 °C, relative humidity of 50% and noise level of 35 dB(A) remained unchanged. Under each of the four conditions of air quality in the office, concentrations of volatile organic compounds (VOCs) were measured and perceived air quality was assessed by a panel of 30 female subjects. Removing the sources reduced the chemical and sensory pollution load in the office, and increasing the outdoor air supply rate decreased concentrations of many VOCs, including those emitted by building materials and furnishing, and human bioeffluents. The perceived air quality in the office was consequently improved. The improvement in air quality obtained by removing the sources was similar to that obtained by increasing the outdoor air supply rate. The study, thus, confirmed that the systematic use of low-polluting building materials will lead to improved air quality.

Abstract Air quality was studied in an office space classified as low-polluting and ventilated with outdoor air at a rate of 1 h−1. The pollution load in the space was changed by introducing or removing common building-related indoor pollution sources (linoleum, sealant and wooden shelves with books and paper documents) so that the space could no longer be classified as low-polluting. The outdoor air supply rate in the office was altered from 1 to 3 h−1 (0.83 and 2.5 l/s per m2 floor, respectively) when sources were present and absent. Air temperature of 23 °C, relative humidity of 50% and noise level of 35 dB(A) remained unchanged. Under each of the four conditions of air quality in the office, concentrations of volatile organic compounds (VOCs) were measured and perceived air quality was assessed by a panel of 30 female subjects. Removing the sources reduced the chemical and sensory pollution load in the office, and increasing the outdoor air supply rate decreased concentrations of many VOCs, including those emitted by building materials and furnishing, and human bioeffluents. The perceived air quality in the office was consequently improved. The improvement in air quality obtained by removing the sources was similar to that obtained by increasing the outdoor air supply rate. The study, thus, confirmed that the systematic use of low-polluting building materials will lead to improved air quality.