Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study
Night ventilation methods have been used in educational buildings to guarantee indoor air quality at the beginning of occupied periods. A typical method has been to pre-start ventilation 2 h before the space usage. Another selection has been to ventilate a building continuously during the night with...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-04-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/11/9/4056 |
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| author | Sami Lestinen Simo Kilpeläinen Risto Kosonen Maria Valkonen Juha Jokisalo Pertti Pasanen |
| author_facet | Sami Lestinen Simo Kilpeläinen Risto Kosonen Maria Valkonen Juha Jokisalo Pertti Pasanen |
| author_sort | Sami Lestinen |
| collection | DOAJ |
| description | Night ventilation methods have been used in educational buildings to guarantee indoor air quality at the beginning of occupied periods. A typical method has been to pre-start ventilation 2 h before the space usage. Another selection has been to ventilate a building continuously during the night with a minimum airflow rate that can dilute material emissions. In this study, the pre-started, continuous, and intermittent ventilation methods were compared by assessing indoor air quality in field measurements. The daytime ventilation was operating normally. The test periods lasted for 2 weeks. Indoor air quality was assessed by measuring the total volatile organic compounds and microbial concentrations using the quantitative polymerase chain reaction method. Additionally, the thermal conditions, carbon dioxide, and pressure differences over the building envelope were measured. The results show that the night ventilation strategy had negligible effects on microbial concentrations. In most cases, the indoor air microbial concentrations were only a few percent of those found outdoors. The averaged concentration of total volatile organic compounds was at the same level with all the night ventilation methods at the beginning of the occupied periods in the mornings. The concentrations reached a minimum level after 2-h ventilation. The concentrations of total volatile organic compounds were higher during the day than at night. This reveals that space usage had the largest effect on the total volatile organic compounds. Generally, the results show that continuous night ventilation does not significantly affect the biological and chemical contaminants. Consequently, a 2-h flushing period is long enough to freshen indoor air before occupancy. |
| first_indexed | 2024-03-10T11:50:11Z |
| format | Article |
| id | doaj.art-71ea935e4f2348058d1234927dddf30b |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T11:50:11Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-71ea935e4f2348058d1234927dddf30b2023-11-21T17:44:29ZengMDPI AGApplied Sciences2076-34172021-04-01119405610.3390/app11094056Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field StudySami Lestinen0Simo Kilpeläinen1Risto Kosonen2Maria Valkonen3Juha Jokisalo4Pertti Pasanen5Department of Mechanical Engineering, School of Engineering, Aalto University, 02150 Espoo, FinlandDepartment of Mechanical Engineering, School of Engineering, Aalto University, 02150 Espoo, FinlandDepartment of Mechanical Engineering, School of Engineering, Aalto University, 02150 Espoo, FinlandDepartment of Health Security, Finnish Institute for Health and Welfare (THL), 70701 Kuopio, FinlandDepartment of Mechanical Engineering, School of Engineering, Aalto University, 02150 Espoo, FinlandDepartment of Environmental and Biological Sciences, University of Eastern Finland, 70211 Kuopio, FinlandNight ventilation methods have been used in educational buildings to guarantee indoor air quality at the beginning of occupied periods. A typical method has been to pre-start ventilation 2 h before the space usage. Another selection has been to ventilate a building continuously during the night with a minimum airflow rate that can dilute material emissions. In this study, the pre-started, continuous, and intermittent ventilation methods were compared by assessing indoor air quality in field measurements. The daytime ventilation was operating normally. The test periods lasted for 2 weeks. Indoor air quality was assessed by measuring the total volatile organic compounds and microbial concentrations using the quantitative polymerase chain reaction method. Additionally, the thermal conditions, carbon dioxide, and pressure differences over the building envelope were measured. The results show that the night ventilation strategy had negligible effects on microbial concentrations. In most cases, the indoor air microbial concentrations were only a few percent of those found outdoors. The averaged concentration of total volatile organic compounds was at the same level with all the night ventilation methods at the beginning of the occupied periods in the mornings. The concentrations reached a minimum level after 2-h ventilation. The concentrations of total volatile organic compounds were higher during the day than at night. This reveals that space usage had the largest effect on the total volatile organic compounds. Generally, the results show that continuous night ventilation does not significantly affect the biological and chemical contaminants. Consequently, a 2-h flushing period is long enough to freshen indoor air before occupancy.https://www.mdpi.com/2076-3417/11/9/4056intermittent ventilationnight purgingindoor air qualityTVOCmicrobes |
| spellingShingle | Sami Lestinen Simo Kilpeläinen Risto Kosonen Maria Valkonen Juha Jokisalo Pertti Pasanen Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study Applied Sciences intermittent ventilation night purging indoor air quality TVOC microbes |
| title | Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study |
| title_full | Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study |
| title_fullStr | Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study |
| title_full_unstemmed | Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study |
| title_short | Effects of Night Ventilation on Indoor Air Quality in Educational Buildings—A Field Study |
| title_sort | effects of night ventilation on indoor air quality in educational buildings a field study |
| topic | intermittent ventilation night purging indoor air quality TVOC microbes |
| url | https://www.mdpi.com/2076-3417/11/9/4056 |
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