Article Air Change in Low and High-Rise Apartments Yonghang Lai 1, Ian A. Ridley 1 and Peter Brimblecombe 1,2,3,4,* 1 School of Energy and Environment, City University of Hong Kong, Hong Kong;
[email protected] (Y.L.);
[email protected] (I.A.R.) 2 Department of Marine Environment and Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan 3 Aerosol Science Research Center, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan 4 School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK * Correspondence:
[email protected] Received: 8 April 2020; Accepted: 8 May 2020; Published: 13 May 2020 Abstract: Air exchange in tall apartment buildings is critical in controlling indoor environments in urban settings. Airtightness is relevant to energy efficiency, thermal comfort and air quality experienced by urban dwellers who spend much of their time indoors. While many air change measurements have been made in residential homes, fewer are available for high-rise apartments. The blower-door and CO2 exchange methods were used to measure air change in some Hong Kong apartment buildings, for comparison with those from other parts of the world. Hong Kong apartments are often small and typical rented apartments show a median of seven air changes per hour under a 50 Pa pressure difference, similar to Mediterranean houses, though much greater than the airtight buildings of Northern Europe. Extrapolation of blower-door measurements made at 50 Pa to the natural pressure difference measured for individual Hong Kong apartments provides an approximation (within 8%) of the natural air change rate measured with a tracer.