The influence of indoor climate on students learning performance

Transcription

1 The influence of indoor climate on s learning performance Teet-Andrus Koiv, Alo Mikola, Aider Saar Department of Environmental Engineering Tallinn Technical University Ehitajate tee 5, Tallinn ESTONIA Teet.koiv@ttu.ee Abstract: - The article gives an overview of indoor climate studies in various schools in Tallinn. It provides an overview of the principle of determining the CO2 level and its effects on performance. The indoor climate in three school buildings was investigated and s relative performance was determined. Because the ventilation in classrooms is modest, s relative performance is not high. This study shows that well-organized ventilation in classrooms is important not only from the aspect of indoor climate comfort, but also significantly affects s performance. Key-words: - Indoor climate of classrooms, determination of the CO2 level, relative performance 1 Introduction Poor indoor air quality (IAQ) in indoor spaces, such as classrooms, can have adverse effects on the s and teachers comfort and pupils learning performance. Over short time scales (hours), poor IAQ causes discomfort, loss of attention and learning ability problems. On the other hand, sufficient ventilation rates in classrooms have been shown to improve s e.g. in mathematics and reading tests [1]. The air rate (ACR) is not sufficient and generally much lower than the mandatory design requirements. During classroom occupation, the indoor concentrations of carbon dioxide (CO2) can rapidly reach the recommended limit values, and this is caused by an inadequate level of ventilation [2]. In the Netherlands several studies in primary schools showed that the CO2 concentration exceeded 1000 ppm more than 80% of the time [3]. The school provides a major indoor environment for children away or apart from their home as they may spend about 10 hours per day at school [4]. Indoor air pollutants might increase the chance of both long and short term health problems among pupils and staff, reduce teachers productivity and degrade pupils learning environment and comfort [5]. Studies done in the United States [9] indicated that good air quality in schools has enhanced attendance and reduced health problems among pupils. Research conducted on five classrooms in Hong Kong indicated that with inadequate ventilation the maximum CO2 level may reach 5900 μl/l during a class [7]. IAQ problems can be attributed to various phases of the building process, including poor site selection, choice of materials, roof design, poor construction quality, improper installation or any number or combination of other factors [8]. Wargocki et al. [9] found that air-conditioned buildings may increase the risk of SBS systems compared to those that are naturally ventilated. ASHRAE [10] recommends a minimum ventilation rate of 8 L/s-person for classrooms. Provided the typical occupant density is 33 per 90 m2 and the ceiling height is 3m, the current ASHRAE standard would require an air rate of about 3 air s per hour (ACH) for a classroom. Clements-Croome et al. [11] in their research of eight primary schools in the United Kingdom revealed that pupils work and performance increased by 7% due to the intervention of fresh air supply from to 16 L/s per person. This is supported by [12], in which small ventilation air flow rates will ISBN:

2 reduce not only comfort, but also schoolchildren s learning performance in classrooms. Improving classroom conditions can substantially improve the performance of school work by children [13]. Indoor CO2 concentrations above 1000 ppm are generally regarded as indicative of ventilation rates that are unacceptable with respect to body odors. Concentrations of CO2 below 1000 ppm do not always guarantee that the ventilation rate is adequate for removing air pollutants from other indoor sources [14]. The paper presents the results of the study into the dependence of learning performance on the indoor climate in three school buildings, which show significant shortcomings in the indoor air quality of the classrooms. 2 Method The air in a classroom can be determined by the in CO 2 concentration using equation (1) [15] m + Cv C L τ = ln L (1) V m + Cv Co L where m - carbon dioxide generation in the room, L - air in the room, V - volume of the room or design volume, C v - carbon dioxide concentration in the external air (in the supply air), C - carbon dioxide concentration in the room air (in the exhaust air), C o - carbon dioxide concentration in the air of the room at the beginning of human activity, τ - time The dependence of relative performance on the air in classrooms together with indicators by various researchers are shown in Fig.1 [16] Fig.1. The dependence of relative performance on the air in classrooms together with indicators by various researchers 3 Results 3.1 Mustamae Secondary School The building was constructed in 1965 and renovated in It has a closed net area of 4615 m2. The heated area is 4586 m2. Most classrooms have southern orientation. The air and relative performance data determined by the CO2 method are shown in Table 1. ISBN:

3 Room base air 6 base air 6 base air 6 chaange chaange chaange Time Average Table 1 and relative performance data (on the example of classroom 111) It can be seen from Table 1 that in the indoor climate conditions in the studied classrooms, the relative performance is from 41 to 93% during different classes. The cumulative distribution of CO2 concentration during a school day is shown in Fig.2. ISBN:

4 Fig. 2. The cumulative distribution of CO2 concentration during a school day. Fig. 3. The cumulative distribution of internal temperature during a school day. 3.2 Mustamae Humanitarian Secondary School The building was constructed in The area of the studied classrooms is m 2. The closed net area of the building is 6628 m 2. Most classrooms have southern orientation. The air and relative performance data are shown in Table 2. The cumulative distribution of CO2 concentration during a school day is given in Fig.4. In the studied classrooms in Mustamäe Humanitarian Secondary School, the relative performance during different classes is higher - from 70 to 96% (Table 2). ISBN:

5 Table 2. and relative performance da Room performance performance performance Base level Base level Base level Time Average Indoor air CO 2 concentration; ppm III klass EVS-EN II klass EVS-EN I klass EVS-EN Time %; 8:00-16:40 Fig.4. The cumulative distribution of CO2 concentration during a school day The cumulative distribution of internal temperature can be seen in Fig.5. ISBN:

6 Fig. 5. The cumulative distribution of internal temperature during a school day 3.3 Pae Secondary School The building was constructed in 1960 and its useful area is 4662 m2. In 2003 the building was renovated. The studied classrooms have southwestern and southeastern orientation. Table 3. and relative performance data The cumulative distribution of CO2 concentration during a school day is given in Fig.6. Table 3 shows that in Pae Secondary School the air results are smaller and the relative performance varies from 41 to 96%. The cumulative distribution of internal temperature can be seen in Fig.7. Room Base level 6 Base level 6 Base level 6 Time Average ISBN:

7 Fig.6. The cumulative distribution of CO2 concentration during a school day Fig.7. The cumulative distribution of internal temperature during a school day 4 Conclusion The article gives an overview of the indoor climate in three secondary schools in Tallinn. The conducted studies showed that due to poor air, the CO2 levels in classrooms exceed the intended level by 2-3 times. As a result, the relative performance indicators are rather modest even falling below 50% at times; % level, however, is quite common. The study clearly demonstrates that wellorganized ventilation in classrooms is important not only from the aspect of indoor ISBN:

8 climate comfort, but it also significantly affects s performance. Acknowledgements The publication of this article was supported by ESF measure Development of cooperation and innovation of universities, the sub-measure "Doctoral Schools", which finances the project "Construction and Environmental Engineering PhD School" project code and the research was supported by the Estonian Research Council, with Institutional research funding grant IUT1 15. References [1] Indoor Quality in Schools - Improving Child Health and Learning Performance. urceid=ie7&rls=com.microsoft:et:ie- Address&ie=&oe=#q=Indoor++Quality+in +Schools+- +Improving+Child+Health+and+Learning+Per formance&rls=com.microsoft:et%3aie- Address [2] Dijken, F., Bronswijk, J.E.M.H. van, Sundell, J., 2006, Indoor environment in Dutch primary schools and health of the pupils, Building Research and information, 34(5), [3] N. M. Salleh, S. N. Kamaruzzaman, R. Sulaiman, N. S. Mahbob Indoor Quality at School: Ventilation Rates and It Impacts Towards Children-A review. 2nd International Conference on Environmental Science and Technology IPCBEE vol.6 (2011), IACSIT Press, Singapore. [4] Zhang G, Spickett J, Rumchev K, Lee AH, Stick S Indoor Environmental quality in a low allergen school and three standard primary schools in Western Australia. Indoor. 16: [5] Soughnessy, R.J., Soughnessy, U.H, Nevalainen, A., Moschandreas, D. (2006). A preliminary study on Association between ventilation rates in classrooms and s performance. Indoor 16, [6] N. M. Salleh, S. N. Kamaruzzaman, R. Sulaiman, N. S. Mahbob Indoor Quality at School: Ventilation Rates and It Impacts Towards Children-A review. 2nd International Conference on Environmental Science and Technology IPCBEE vol.6 (2011), IACSIT Press, Singapore. [7] Lee, S., and Chang, M.(1999). "Indoor air quality investigations at five classrooms." Indoor, 9, p [8] Hall, R., Hardin, T., and Ellis, R. (1995). "School indoor air quality best practices manual." Washington State Department of Health, Olympia, Washington. [9] Research Triangle Institute International. (2003). "California Portable Classrooms Study Project Executive Summary." California Resources Board, California Department of Health Services. [10] Wargocki, P., Sundell, J., Bischof, W., Brundrett, G., Fanger, P. O., Gyntelberg, F., Hanssen, S. O., Harrison, P., Pickering, A., Seppanen, O., Wouters, A. (2002). "Ventilation and health in non-industrial indoor environments: report from a European Multidisciplinary Scientific Consensus Meeting (EUROVENT)." Indoor, 12, p [11] ASHRAE (2007) Ventilation for acceptable indoor air quality, standard , American Society for Heating, Refrigerating and Conditioning Engineers, Atlanta, GA. [12] D.J Clements-Croome et al. (2008). Ventilation rates in schools. Building and Environment, 43, p [13] Wargocki et al. (2005). The effects of classroom air temperature and outdoor air supply rate on the performance of school work by children. Indoor proceeding. Danish Technical Research. [14] Sahlberg, B., Smedge, G., Norback, D. (2002). "Sick Building Syndrome (SBS) Among School Employees in the County of Uppsala, Sweden." In: Indoor 2002, Monterey, California. [15] T.-A.Koiv. Indoor climate and ventilation in Tallinn school buildings. Proc. Estonian Acad. Sci.Eng., 2007, 13, 1, [16] REHVA GUIDBOOK no.13. Indoor Environment and Energy Efficiency in Schools. ISBN: