The built environment has a fundamental role in maintaining public health. What lessons has Hong Kong applied to reduce the spread of contagion?
An important function of the built environment
is providing a safe place for its inhabitants.
Edward Ng (Chinese University of Hong Kong) recalls the spread of SARS in Hong Kong and reflects on the public health lessons for the built environment. A process of preparation and management is vital for
reducing present and future health risks. This is becoming evident in Hong Kong’s
recent codes and regulations for urban design and buildings . Other cities can learn from this process.
Dr Liu (patient zero) arrived in Hong Kong from Guangdong in February 2003. He stayed in a hotel downtown. It was a small and busy hotel. Dr Liu was not well and was coughing. Little did he realize that he infected 9 others in the confined spaces of the hotel -- lobby, lifts and corridors. Dr Liu died on 4 March 2003. The 9 individuals he infected, mostly tourists, later left Hong Kong and subsequently caused the worldwide outbreak of SARS where more than 2300 people in 17 countries were infected eventually. 80 lives were lost. (HKSARG, 2003)
Within a month, SARS rapidly spread to Hong Kong population (Lee, 2003). Amoy Gardens is a typical housing estate the metro area in Hong Kong. Soon after the first case was reported on 14 March, more than 300 cases were recorded by early April; they were mostly concentrated in 3 building blocks closely located to each other.
Subsequent studies reveal that the diseases spread from the toilet of an inhabitant on the 16th floor in Block E into the re-entrant space, and travelled upward to the other floors (Figure 1).
The widely reported saga was the most important wakeup call for policy makers, regulators, stakeholders, developers, planners and architects in Hong Kong. The media message to the general public was clear: the planning and design of buildings is an important consideration for healthy living.
FIGURE 1. LEFT: The spread of the SARS contagion through buildings was only revealed by research after the epidemic subsided. The infection spread to the occupants via the vertical drainage pipe. This then spread to the occupants on the floors above via windows. (Gormley et al., 2017) CENTRE and RIGHT: Contaminated droplets from the 16th floor escaped and were carried via buoyancy effect to the other floors. (Lee, 2012)
After the SARS episode subsided, the Government of Hong Kong Special Administrative Region (HKSAR) began an investigation into the spread of SARS (to learn the lessons from the Amoy Gardens) in order to reduce future risks. It established a Team Clean Commission to coordinate the efforts (Team Clean, 2003). One of the Commission’s recommendations was that outdoor air circulation should be factored into future planning and design practices. The other recommendation was that planners should evaluate and establish the city’s air circulation capacity and its relationship with the city’s development densities and building layouts. The public health basis for the recommendations was to improve ventilation of indoor and outdoor spaces so as to quickly mix the contaminated air and dilute its germ concentration, and thereby prevent spread of disease due to cross contamination in confined spaces (Nielsen, 2009; McKinney et al., 2006).
To address the faulty drainage design, the Buildings Department of the HKSAR Government issued new Practice Notes for Authorised Persons (PNAP=App93). The new W-trap design would prevent the drying of the water seal in the floor U trap (BD, 2014). In addition, two important building and urban design guidelines were promulgated. The first was the Air Ventilation Assessment (AVA) Technical Circular (DevB, 2006); the other was a new chapter on city-building ventilation principles in the Hong Kong Planning Standard and Guidelines (HKPSG). These two documents have since guided the construction industry in Hong Kong towards planning and designing a healthier city for high density living.
The first building project that made reference to the Technical Circular and the new chapter on city-building ventilation in the HKPSG was the Hong Kong Government Headquarters building in Tamar. The large opening responded to the computational fluid dynamics (CFD) and wind tunnel test results to improve microclimatic conditions.
FIGURE 2. The Tamar Hong Kong SAR Government Headquarters designed to Air Ventilation Assessment Technical Circular and HK Planning Standards and Guidelines for better urban ventilation (ArchDS, 2013).
SARS was not the only alarm to the construction industry stakeholders and policy makers in the history of Hong Kong. In 1894, Hong Kong suffered the deadlier Bubonic Plague that eventually killed more than 20,000 people. British sanitary engineer Osbert Chadwick evaluated the situation and recommended that the poor sanitary standard and the overcrowded living environment were the key concerns. In particular, he pointed to the lack of fresh air and sunlight in narrow streets and poorly designed back-to-back houses. In 1903, the Hong Kong Government enacted the Public Health and Building Ordinance to regulate the city. Some metro areas of the city were re-built according to the new regulations. In hindsight, the urban structure of metro Hong Kong has become what it is today mainly because of this 1903 Public Health and Building Ordinance, which was a response to the 1894 Bubonic Plague.
As this commentary is being written, COVID-19 is still with us. By April 2020, more than 2 million cases and over 120,000 deaths worldwide have been reported. The world is still fighting the pandemic. Lessons from how the HKSAR Government fought SARS are currently being applied: the borders are controlled, travel is restricted, gatherings are prohibited, stay home orders are issued, schools are closed, and people are advised to wear face masks, to wash hands more often and to keep a safe distance from each other. All the public health precautionary measures are in place.
Unlike SARS in 2003, COVID-19 lingers much longer and affects more countries in the world. As such, the above precautionary public health measures will be with us longer. Apart from the economic problems that governments around the world are now trying to solve, the construction industry stakeholders and policy makers are beginning to talk about how we can design a more “disease resilient” and healthier built environment. For researchers in the field of buildings and cities, there are scholarly implications that are worth pondering over, and the subject matter requires further research.
How can our buildings and cities be designed to provide physically healthy and “disease resilient” indoor and outdoor spaces? From the built environmental perspective, public health doctors have repeatedly reminded us these three keywords: “distance”, “fresh air” and “sunlight”.
How can our buildings and cities be designed to provide mentally healthy spaces to cope with future episodes? Isolation and quarantine may be necessary during a pandemic, but are unpleasant and difficult experiences. Environmental psychologists have pointed to three key built environmental provisions that are spatially related: “social interaction”, “nature & openness” and “exercise”.
The precise definitions and metrics of these six keywords will require further evidence. These insights will provide additional meanings and precautions when designing our buildings and cities for health and wellness, green, sustainable, low carbon, resilient, regenerative criteria.
The World Health Organisation’s definition of a healthy city is a useful starting point:
"one that is continually creating and improving those physical and social environments and expanding those community resources which enable people to mutually support each other in performing all the functions of life and in developing to their maximum potential." (WHO, 1998)
The definition is broad and it is often graphically represented as The Rainbow Model. There are many issues that are related to buildings and cities. WHO’s holistic model would allow every city to develop its own priorities and balance its focuses.
Based on this model, this understanding can be contextualised for policy makers in Hong Kong:
Furthermore, beyond diseases, the hotter and more extreme environment as a result of climate change will bring further heat-stress mortality (Lee, 2011). To migrate 1 C higher urban air temperature, the ventilation flow rate needs to increase by 0.4 m/s (Höppe, 1999). Future buildings and cities need to be designed to improve microclimate and ventilation at the urban, neigbourhood and street levels.
In summary, how we design our buildings and cities to address the six keywords -- “distance”, “fresh air” and “sunlight”, “social interaction”, “nature & openness” and “exercise” – will be topical questions for scholars.
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