Qun Wang

• Doctor of Philosophy
• Assistant Professor at The Macau University of Science and Technology

Typhoons, among the most devastating natural hazards, have caused billions in property losses and posed significant threats to human safety globally. Damage to urban structures, particularly building windows, constitutes a major component of direct losses caused by typhoons. This study investigates wind impacts on buildings using large-eddy simulat...

The lack of knowledge on quanta generation rates presents a major obstacle to specifying the minimum ventilation required to prevent airborne infections. The expected largest quanta generation rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by a super-spreader remains unknown. Here we investigated a SARS-CoV-2 outbreak during l...

Background Interprofessional education (IPE) has the potential to shape students’ collaboration perception and interprofessional identity but remains understudied. This study aims to understand the effects of the IPE program as a contextual trigger to promote collaboration perception change and interprofessional identity formation among healthcare...

The phenomenon of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in high-rise residential buildings (HRRBs) is unique in our densely populated cosmopolitan city. The compulsory testing of a whole building under the scheme of restriction-testing declaration (RTD) during the fourth wave (non-Omicron variant) and...

Leading health authorities have suggested short-range airborne transmission as a major route of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). However, there is no simple method to assess the short-range airborne infection risk or identify its governing parameters. We proposed a short-range airborne infection risk assessment model ba...

A COVID-19 outbreak occurred in May 2020 in a public housing building in Hong Kong – Luk Chuen House, located in Lek Yuen Estate. The horizontal cluster linked to the index case’ flat (flat 812) remains to be explained. Computational fluid dynamics simulations were conducted to obtain the wind-pressure coefficients of each external opening on the e...

Rapid urbanisation and rising vehicular emissions aggravate urban air pollution. Outdoor pollutants could diffuse indoors through infiltration or ventilation, leading to residents’ exposure. This study performed CFD simulations with a standard k-ε model to investigate the impacts of building configurations and tree planting on airflows, pollutant (...

Poor housing conditions are known to be associated with infectious diseases such as high Coronavirus disease 2019 (COVID-19) incidences. Transmission causes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in poor housing conditions can be complex. An understanding of the exact mechanism of transmission can help to pinpoint contribut...

Vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) along a vertical column of flats has been documented in several outbreaks of coronavirus disease 2019 (COVID-19) in Guangdong and Hong Kong. We describe an outbreak in Luk Chuen House, involving two vertical columns of flats associated with an unusually connected...

Airborne transmission of SARS-CoV-2 has been increasingly recognized in the outbreak of COVID-19, especially during the emergence of Omicron variant. We investigated an outbreak due to Omicron variant in a restaurant. Besides the epidemiological and phylogenetic analysis, the secondary attack rates of customers of restaurant-related COVID-19 before...

Stack aerosols are generated within vertical building drainage stacks during the discharge of wastewater containing feces and exhaled mucus from toilets and washbasins. Fifteen stack aerosol-related outbreaks of coronavirus disease 2019 (COVID-19) in high-rise buildings have been observed in Hong Kong and Guangzhou. Currently, we investigated two s...

Mechanical ventilation consumes a huge amount of global energy. Natural ventilation is a crucial solution for reducing energy consumption and enhancing the capacity of atmospheric self-purification. This paper evaluates the impacts of indoor-outdoor temperature differences on building ventilation and indoor-outdoor air pollutant dispersion in urban...

The increased intensity of extreme weather events (e.g., heatwaves) that is predicted to occur due to global climate change could significantly impact human health, biodiversity, and infrastructure integrity in cities. As one of the most densely constructed cities in the world, Hong Kong has been experiencing increasingly intense heatwaves in recen...

The urban moisture island (UMI) can aggravate the thermal stress due to the urban heat island (UHI) in subtropical and tropical cities. In this study, we investigated the spatiotemporal variation patterns of UMI in Hong Kong, a subtropical coastal city, using the fine-resolution mesoscale Weather Research and Forecasting (WRF) model by integrating...

Contaminants, such as pathogens or non-living substances, can spread through the interaction of their carriers (e.g., air and surfaces), which constitute a network. The structure of such networks plays an important role in the contaminant spread. We measured the contaminant spreading efficiency in different networks using a newly defined parameter....

The unsteady approaching flow (UAF) and its influence upon the flow pattern within street canyon are investigated from a perspective of mechanism in this study. Based on wind tunnel test (WTT) measurements, the boundary conditions for the approaching flow over 2D street canyons (H/W = 2.4) are described in continuous functions of reference velocity...

With the booming concerns over urban heat island phenomenon, impacts of solar radiation on flow and temperature in street canyons have been revealed by some experimental and numerical investigations, where amplified single-vortex structures are found in shallow canyons in high-Re scenarios (Re ~ 10⁷). Canyon surfaces are heated mainly by absorbing...

Changes in urban geometry significantly alters the urban microclimate. Suitable urban geometrical layouts can effectively improve the urban thermal environment to achieve a more sustainable and healthier city. A quantitative assessment of the relationship between the urban geometry and thermal environment is essential to provide scientific guidance...

Considering the influence of natural solar heating, this paper numerically evaluated the sustainability of various urban street layouts from three different views: the pedestrian-level ventilation capacity assessed by the normalized net escape velocity NEVped; the transport and removal processes of heat and vehicular pollutant across the street top...

Severe haze episodes and extreme heat events are both related to the strong inversion in the atmospheric boundary layer. Inversion breakup is the main mechanism to alleviate the accumulation of heat or pollutants, especially in urban areas. However, the physical process and turbulent flow structures of inversion breakup remain unclear. In this stud...

This study incorporates solar radiation model and NOx-O3 photochemistry into computational fluid dynamics (CFD) simulations with the standard k-ε model to quantify the integrated impacts of turbulent mixing, solar heating and chemical processes on vehicular passive (CO) and reactive (NOx, O3) pollutant dispersion within two-dimensional (2D) street...

Natural convection flow above a heated horizontal area plays a major role in energy utilisation, indoor/outdoor thermal environment, city ventilation and pollutant dispersion. Such natural convection can present different flow patterns, and identifying the type of flow pattern is crucial for determining the bulk heat transfer coefficient. Water tan...

Wind-driven dynamic force and buoyancy force are two main driving forces in urban ventilation. As a novelty, this paper performs scaled outdoor measurements to examine the relative role of these two driving forces by non-dimensional buoyancy parameter B within two-dimensional (2D) street canyons in SOMUCH (Scaled Outdoor Measurement of Urban Climat...

The adverse environmental impacts of the urban heat island (UHI) phenomenon have been known amid rapid urbanization in many parts of the world. UHI-induced circulation (UHIC) can affect pollutant dispersion and heat exchange. An UHIC can transform into an urban plume (or perturbed UHIC) in the presence of regional wind. To understand the urban plum...

The Beijing-Tianjin-Hebei region has experienced severe urban heat island (UHI) effects in recent decades. Using the Weather Research and Forecasting (WRF) model and the new World Urban Database and Access Portal Tools (WUDAPT) land-use dataset, the urban heat island circulations (UHICs) and other local atmospheric circulations over Beijing and Tia...

Street aspect ratios and urban thermal storage largely determine the thermal environment in cities. By performing scaled outdoor measurements in summer of 2017 in Guangzhou, China, we investigate these impacts on spatial/temporal characteristics of urban thermal environment which are still unclear so far. Two types of street canyon models are inves...

Validated by experimental data, this paper performs computational fluid dynamics (CFD) simulations to investigate the influence of tree plantings on urban airflow and vehicular CO exposure in two-dimensional (2D) street canyons with various aspect ratios (building height/street width, AR = H/W = 0.5, 1, 3, 5) and ground-level source. The impacts of...

Deep street canyons and unfavourable meteorological conditions usually induce high pollutant exposure. Validated by experimental data, this paper employs computational fluid dynamic simulations with RNG k-ε model to investigate the flow, and passive pollutant dispersion within scale-model two-dimensional street canyons(H = 3 m). As a novelty, this...

Natural convection over an isolated horizontal plate in a stably stratified background condition is fundamental and challenging in industrial, atmospheric, geographical, and oceanic environmental studies, which, however, is still lack of investigation. In this study, the water tank modelling experiment with two main techniques, Thermal Image Veloci...

Air pollution and extreme heat waves are among the major environmental challenges faced by modern cities. Stable stratification and temperature inversion help to trap urban airborne pollutants and produce a strong urban heat island intensity. Such adverse effects can disappear when the buoyancy flows introduced by the city heat is sufficiently stro...

Extreme heatwaves and air pollution in urban areas often occur in calm and stable background conditions. In such situations, urban heat dome flows are induced by the urban heat island (UHI) effect, which has a strong influence on the urban thermal and wind environment. Cities have various shapes, but most studies of urban heat island circulation ha...

This paper presents a numerical study of two interacting urban heat island circulations (UHICs) in the presence of weak background wind. The Weather Research and Forecasting (WRF) model was used with ideal settings without the Earth's rotation effect. UHICs were simulated over circular cities of the same size arranged in tandem or side by side with...

The Weather Research and Forecasting (WRF) Model is used to study the interaction between urban heat island circulation (UHIC) and its background wind. Two distinct wind regimes are found depending on the ratio of the horizontal convective scale velocity to the background velocity, which is referred to as the buoyancy velocity ratio. When the buoya...

The microclimate of a high-density city affects building energy consumption and thermal comfort. Despite the practical needs in building design and urban planning to predict conditions inside street canyons, literature is sparse for physics-based models that can support early stage design. Existing tools such as the Computational Fluid Dynamics (CF...

Building thermal mass is significant to influence urban climate. We performed scale-model field measurement of thermal environment and turbulence in summer of 2015 in Guangzhou, China. Two types of scale-model were used to arrange north-south street canyons (the ‘empty’ model with wall thickness of 1.5 cm and the ‘sand model’ in which all buildings...

Previous researchers calculated air change rate per hour (ACH) in the urban canopy layers (UCL) by integrating the normal component of air mean velocity (convection) and fluctuation velocity (turbulent diffusions) across UCL boundaries. However they are usually greater than the actual ACH induced by flow rates flushing UCL and never returning again...

This paper investigates pollutant removal at pedestrian level in urban canopy layer (UCL) models of medium packing density (λp = λf = 0.25) using computational fluid dynamics (CFD) simulations. Urban size, building height variations, wind direction and uniform wall heating are investigated. The standard and RNG k-ε turbulence models, validated agai...