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Digital transformation has been inevitable in all socio-economic fields, including higher education. Recently, under the burden of the COVID-19 pandemic, many universities have to change their entire teaching systems to online learning to ensure their students' learning is not interrupted. Thus, it is essential to study how universities' students, educators, and administrators perceive online learning in different countries. To this aim, this study investigates the factors affecting university members' preference for online learning in Singapore and Vietnam. Using a cross-country sample with a sound theoretical framework of the Technology Acceptance Model (TAM), we found that each member group in the university was influenced by a different weight of factors. Specifically, students' preference for online learning is most affected by their technical skills. Meanwhile, educators and administrators are influenced mainly by the perceived usefulness of online learning and practice conditions, respectively. We further conducted multi-group testing and confirmed the certain separation in online learning preferences of observed objects between the two countries. Overall, this paper enriches the literature on online education, and has important implications for educational policymakers and university stakeholders both during and after the pandemic.

Black carbon (BC), an important indicator of traffic-related air pollution (TRAP) in urban environments, is receiving increased attention because of its adverse health effects. Personal exposure (PE) of adults to BC has been widely studied, but little is known about the exposure of young children (toddlers) to BC in cities. We carried out a pilot study to investigate the integrated daily PE of toddlers to BC in a city-state with a high population density (Singapore). We studied the impact of urban traffic on the PE of toddlers to BC by comparing and contrasting on-road traffic flow (i.e., volume and composition) in Singapore in 2019 (before the COVID-19 pandemic) and in 2020 (during the COVID-19 pandemic). Our observations indicate that the daily BC exposure levels and inhaled doses increased by about 25% in 2020 (2.9 ± 0.3 μg m−3 and 35.5 μg day−1) compared to that in 2019 (2.3 ± 0.4 μg m−3 and 28.5 μg day−1 for exposure concentration and inhaled dose, respectively). The increased BC levels were associated with the increased traffic volume on both weekdays and weekends in 2020 compared to the same time period in 2019. Specifically, we observed an increase in the number of trucks as well as cars/taxis and motorcycles (private transport) and a decline in the number of buses (public transport) in 2020. The implementation of lockdown measures in 2020 resulted in significant changes in the time, place and duration of PE of toddlers to BC. The recorded daily time-activity patterns indicated that toddlers spent almost all the time in indoor environments during the measurement period in 2020. When we compared different ventilation options (natural ventilation (NV), air conditioning (AC), and portable air cleaner (PAC)) for mitigation of PE to BC in the home environment, we found a significant decrease (>30%) in daily BC exposure levels while using the PAC compared to the NV scenario. Our case study shows that the PE of toddlers to BC is of health concern in indoor environments in 2020 because of the migration of the increased TRAP into naturally ventilated residential homes and more time spent indoors than outdoors. Since toddlers' immune system is weak, technological intervention is necessary to protect their health against inhalation exposure to air pollutants. [Display omitted] • Our case study shows daily toddler's exposure to BC is higher in 2020 than in 2019. • An increase in the number of private transports was observed. • We also found a decline in the number of public transport. • The portable air cleaner is most effective at reducing indoor BC. [ABSTRACT FROM AUTHOR]

• Elevated indoor levels of biomass burning derived-PM were observed in Singapore. • Air cleaner is most effective at reducing indoor PM with minimal energy consumption. • The operational cost of IAQ control while using air cleaner is low. • Thermal comfort provided by air cleaner is within the acceptable range. • Health risk associated with inhalation exposure is reduced following PM removal. During the 2019 smoke haze episode in Singapore, elevated levels of fine particulate matter (PM 2.5) were observed, deteriorating both ambient and indoor air quality (IAQ). We investigated the mitigation of indoor human exposure to PM 2.5 of outdoor origin under diverse exposure scenarios with and without filtration of PM 2.5 during both hazy and non-hazy days. The key objective of our study was to make a comparative evaluation of the effectiveness of portable air cleaners (PACs) and air conditioning (AC) systems equipped with particle filters in improving IAQ and to assess related long-term carcinogenic and non-carcinogenic health risks. We conducted real-time measurements of PM 2.5 , black carbon mass concentrations and particle number concentrations in both indoor and outdoor areas, quantified the relative concentrations of the water-soluble fraction of toxic trace elements in PM 2.5 for health risk assessment, and estimated the levels of thermal comfort. In addition, we calculated the total estimated cost of indoor air pollution control. Our findings suggest that indoor air cleaners are more effective at mitigating human exposure to airborne particles and reducing health risk with less consumption of electricity and better cost-effectiveness compared to AC. This information would be beneficial for public health interventions during major air pollution events. [ABSTRACT FROM AUTHOR]

• Personal exposure to PM 2.5 and BC in Danang(Vietnam) and Singapore was assessed. • Exposure to PM 2.5 and BC by commuters was much higher in Danang than Singapore. • Exposure to PM 2.5 and BC in homes should also be considered. • Heavy-duty vehicles and motorcycles are the major contributors to PM in both cities. • Health effects of motorized transport can be avoided by switching to active mobility. The present study investigated the personal exposure (PE) of commuters to fine particles (PM 2.5) and black carbon (BC) in two cities: Singapore and Danang (Vietnam) with different socio-economic conditions. The PE measurement was conducted during a multimodal round trip from Singapore to Danang and back with various on-road transport modes in urban micro-environments within each city by using portable devices. Real-time assessment of PE revealed that more than 60% of the integrated inhaled dose of PM 2.5 by commuters to occurred at airport concourses and transit micro-environments to/from the aeroplane by apron bus. Whereas for BC, the transit by apron bus made a major contribution (> 50%) to the total integrated exposure. The PE to PM 2.5 and BC in transport micro-environments was an order of magnitude higher in Danang compared to Singapore while using various on-road modes of transport in each city. Elevated concentrations of airborne particles in Singapore and Danang were significantly contributed by heavy-duty diesel vehicles and motorcycles, respectively. Moreover, a reduction in years of life expectancy is likely to occur among urban commuters while using motorized transport compared to active mobility (cycling). [ABSTRACT FROM AUTHOR]

• Influence of air quality on bikeability index was evaluated. • The proposed air quality sub-index involves cyclists' exposure to PM 2.5 and BC. • Open-source data, land-use regression models, and deep neural network were utilized. • Cyclists' exposure to TRAP is a significant component of the bikeability index. • The proposed framework is useful for recommending cycling routes in cities. Previous studies on bikeability/cycling index have explored factors that influence cycling in cities, and developed indicators to characterize a bicycle-friendly environment. However, despite its strong influence on cycling behavior, cyclists' exposure to traffic-related air pollution has been often disregarded. To close this knowledge gap, we propose a comprehensive bikeability index that comprises four sub-indices: accessibility, suitability, perceptibility, and prevailing air quality in the vicinity of cycling routes. We evaluate cyclists' exposure to fine particulate matter and black carbon, and used open-source data, land-use regression models, deep neural networks and spatial analysis. The application of the proposed bikeability framework reveals that the inclusion of air quality makes a significant difference when calculating bikeability index in Singapore and hence it merits serious consideration. We believe that the newly developed framework will convince city planners to consider the importance of assessing cyclists' exposure to airborne particles when planning cycling infrastructure. [ABSTRACT FROM AUTHOR]