Electrostatic Precipitator Design Optimization for the Removal of Aerosol and Airborne Viruses

In the midst of the COVID-19 pandemic, new requirements for clean air supply are introduced for heating, ventilation, and air conditioning (HVAC) systems. One way for HVAC systems to efficiently remove airborne viruses is by filtering them. Unlike disposable filters that require repeated purchases of consumables, the electrostatic precipitator (ESP) is an alternative option without the drawback of reduced dust collection efficiency in high-efficiency particulate air (HEPA) filters due to dust buildup. The majority of viruses have a diameter ranging from 0.1 μm to 5 μm. This study proposed a two-stage ESP, which charged airborne viruses and particles via positive electrode ionization wire and collected them on a collecting plate with high voltage. Numerical simulations were conducted and revealed a continuous decrease in collection efficiencies between 0.1 μm and 0.5 μm, followed by a consistent increase from 0.5 μm to 1 μm. For particles larger than 1 μm, collection efficiencies exceeding 90% were easily achieved with the equipment used in this study. Previous studies have demonstrated that the collection efficiency of suspended particles is influenced by both the ESP voltage and turbulent flow at this stage. To improve the collection efficiency of aerosols ranging from 0.1 μm to 1 μm, this study used a multi-objective genetic algorithm (MOGA) in combination with numerical simulations to obtain the optimal parameter combination of ionization voltage and flow speed. The particle collection performance of the ESP was examined under the Japan Electrical Manufacturers' Association (JEMA) standards and showed consistent collection performance throughout the experiment. Moreover, after its design was optimized, the precipitator collected aerosols ranging from 0.1 μm to 3 μm, demonstrating an efficiency of over 95%. With such high collection efficiency, the proposed ESP can effectively filter airborne particles as efficiently as an N95 respirator, eliminating the need to wear a mask in a building and preventing the spread of droplet infectious diseases such as COVID-19 (0.08 μm–0.16 μm). © 2023 by the authors.

Public assessments of ministerial leadership in times of national crisis: The case of the pandemic crisis

Public administration and political science researchers have debated what constitutes effective ministerial leadership in presidential governments. Some argue that, looking at it from the chief executive's perspective, ministers ought to be capable of supporting her policy programs, but others, taking the bureaucrats' point of view, contend that ministers need to be experienced in managing agencies and executing policy correctly. However, there has been a lack of research on the public assessments of ministerial leadership, particularly in times of crisis. We contribute experimental evidence by analyzing original survey data on more than 1200 South Korean citizens collected during the COVID-19 pandemic. We find that, overall, citizens are more likely to endorse ministers' technical expertise and management abilities than their political skills during a crisis. Moreover, as the impact of a national crisis becomes more severe, the levels of support enjoyed by ministers with technical expertise increase more than the support given to ministers with other skills.

Social media use, psychological well-being and physical health during lockdown

In efforts to curb the spread of COVID-19, many countries have implemented a variety of lockdown and quarantine measures. With substantially reduced face-to-face interactions, many people may have relied heavily on social media for connection, information, and entertainment. However, little is known about the psychological and physical health implications of social media use during strict lockdown. The current study investigates the associations of social media use with psychological well-being and physical health among Wuhan residents (N = 1214). Our findings showed that non-COVID related self-disclosure was positively associated with psychological well-being, while COVID related information consumption and sharing were negatively associated with psychological well-being. Further, more generic use of social media was associated with lower psychological well-being, which in turn related to more somatic symptoms. Quarantined people used social media more frequently than non-quarantined people. Importantly, the negative association between social media use and psychological well-being was significantly stronger for quarantined people than unquarantined people.

Quantifying aviation’s contribution to global warming

Growth in aviation contributes more to global warming than is generally appreciated because of the mix of climate pollutants it generates. Here, we model the CO2 and non-CO2 effects like nitrogen oxide emissions and contrail formation to analyse aviation’s total warming footprint. Aviation contributed approximately 4% to observed human-induced global warming to date, despite being responsible for only 2.4% of global annual emissions of CO2. Aviation is projected to cause a total of about 0.1 °C of warming by 2050, half of it to date and the other half over the next three decades, should aviation’s pre-COVID growth resume. The industry would then contribute a 6%–17% share to the remaining 0.3 °C–0.8 °C to not exceed 1.5 °C–2 °C of global warming. Under this scenario, the reduction due to COVID-19 to date is small and is projected to only delay aviation’s warming contribution by about five years. But the leveraging impact of growth also represents an opportunity: aviation’s contribution to further warming would be immediately halted by either a sustained annual 2.5% decrease in air traffic under the existing fuel mix, or a transition to a 90% carbon-neutral fuel mix by 2050.