Building Better
Employing Air Purifiers and Effective Ventilation to Improve Indoor Air Quality in Classrooms View Digital Media
Paper Presentation in a Themed Session Constantinos Sioutas
The scope of this study is to illustrate the effectiveness of ventilation and air purification systems in reducing indoor pollutants concentrations in densely seated classrooms. Real-time measurements of particulate mass (PM), particle numbers (PN), and CO2 concentrations were conducted in occupied classrooms. In addition, a series of tests employing an aerosol-generating system were carried in an empty classroom in order to evaluate air cleaner removal efficiency in the existence of indoor pollution source (i.e., NaCl). The results of this study show a significant contribution of the ventilation systems equipped with efficient filters in maintaining the indoor air quality in classrooms. In the first scenario, the mechanical ventilation system reduced ambient PM and PN by more than 80%. The indoor-to-outdoor concentration ratios (I/O) were relatively low (0.1 or less) in most classrooms due to the presence of in-line air filters in the ventilation systems, which did not allow the air cleaner to show considerable reductions in indoor PM and PN. The results in the empty classroom showed the efficient use of HEPA air cleaner since it significantly increased the particles decay rates. The decay rate value increased on average from 4-4.7 hr-1 in the natural condition to 6.5-6.7 hr-1 with the use of cleaner at high flow rate, which indicates the effective work of the cleaner unit in reducing indoor air pollution. This work highlighted the importance of classroom air pollution mitigation measures in light of the continuous spread of SARS-CoV-2 variants and the return of classes in-person attendance.
Untangling the Everyday Affects of Smart City Living: A Singapore Case Study View Digital Media
Paper Presentation in a Themed Session Nurul Amillin Hussain
This paper examines the experience of individuals in urban spaces that have been planned as ‘smart’ through the inclusion of smart technologies. It explores how individuals encounter these everyday spaces in unintended ways when they (dis)engage with smart technologies. Based on ethnographic fieldwork and interviews with public housing residents in Singapore, this paper draws attention to the nuanced everyday engagements individuals have with smart technologies. Firstly, some technologies have been introduced in these spaces as part of larger smart urbanism projects that individuals do not engage with. Here, the disconnect between the top-down implementation of smart urbanism and its realisation on the ground creates tension that can be understood through dynamic affections and disaffections. Secondly, there are non-technological aspects of living in these smart estates that emerge as significant, such as green spaces. Here, there were tensions between the dual desires for green spaces and increased convenience and access to facilities and services through development. This paper shows how there are entanglements beyond the technological that implicate broader socio-political and cultural processes and impact what it means to be entangled in the mechanisms of a smart city. Thus, this paper moves beyond demonstrating how smart technologies are reconfiguring everyday spaces and urban relations and assessments of the smart city as good or bad. Instead, this paper highlights the value of the affective and emotional landscapes of the everyday in understanding the realisation of smart urbanism from the perspective of smart city residents.
Natural Ventilation in the Climate Crisis: Simulating Wind- and Buoyancy-driven Flow Using Scale Model Measurements in a Wind Tunnel View Digital Media
Paper Presentation in a Themed Session Christina Higgins
A significant portion of office buildings rely on mechanical ventilation, leading to substantial energy consumption and CO2 emissions, and this is a barrier to achieving Net Zero in the sector. Natural ventilation offers a more sustainable alternative, but its effectiveness depends on various factors, including the influence of wind- and buoyancy-driven airflow. Buoyancy-driven flow arises from temperature differences between indoor and outdoor environments and is influenced by internal heat sources such as occupants and equipment. This study investigates wind- and buoyancy-driven ventilation rates with tracer gas decay measurements in an atmospheric wind tunnel, using a scale model of an existing office space. Different window configurations and wind directions were tested, with temperature differences simulated by carrier gases of varying densities. Results indicate that for certain wind directions, buoyancy forces dominate the ventilation flow, and even in wind-driven scenarios, buoyant effects can contribute to higher ventilation rates. Considering buoyancy-driven flow could improve the assessment of natural ventilation feasibility, contributing to more sustainable building design and retrofit.
