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KTKZ5
September 2021
Graph 1.1 The conflicts and tradeoffs arising in terms of IAQ and thermal comfort in a classrooms Source Author
The major IEQ parameters affecting an indoor environment in a school are Ventilation rate, Indoor and Outdoor pollutant concentration arising due to the opening of windows. A minimum ventilation rate of 8 liters per second is mentioned in Building Bulletin 101( BB101) (Funding, 2016).Due to the ongoing COVID 19 pandemic World Health Organization (WHO) and The Federation of European Heating,
Ventilation and Air Conditioning associations (RHEVA) sets 15l/s/person as a minimum ventilation rate when the space is fully occupied (REHVA, Federation of European Heating, 2012). Graph 1.1 explains that when there is decreased ventilation the Carbon dioxide (CO2) level in the indoor environment increases (Mahyuddin and Awbi, 2012). Increased CO2 levels affect the cognitive performance of students (Authority et al., no date). It also causes fatigue and SBS (Sick building syndrome) and increased absenteeism (Shendell et al., 2004). On the contrary improved ventilation of about 20l/s/person, level enables students learning efficiency by improving their alertness and by maintaining health.CO2 level of less than 800ppm can repress Sick building syndrome (Seppänen, 1999). An adequate level of ‘fresh air’ supply helps in improving the indoor air quality by diluting the indoor pollutant concentration level (Turanjanin et al., 2014). The tradeoff of the naturally ventilated building is that as the ventilation increase it carries the outdoor air pollutant contaminants like PM 2.5, PM10, and NO2, O3 within the classroom environment. But, in the context of London, UK, the outdoor air pollutant concentrations like NO2 and PM2.5 are higher in the urban roadside area (Department for Environment Food and Rural Affairs, 2007). Both Long term and short-term exposures to these contaminants affect lung functioning and induce asthma (Quality and Group, no date) (Chan et al., no date). Apart from the pollutants, the major conflict arises when there is increased solar thermal gain during the summer. This causes summertime overheating and brings discomfort to the students and teachers, overheating affects cognitive performance and sense of wellbeing (Simion, Socaciu and Unguresan, 2016). Apart from these Occupants can play a big role in indoor air quality, particularly through the window opening.
1.1 Research overview Most of the existing research studies mainly focus on the ways how outdoor pollutants enter rooms. There are not many studies on occupant behaviours and IAQ and thermal comfort in the UK or temperate climate/ cold regions. Due to climate change and urban heat islands (UHI), the global
UCL Institute of Energy and Environmental Engineering
BSEER
September 2021
