Advances in particulate matter filtration: Materials, performance, and application

Air-borne pollutants in particulate matter (PM) form, produced either physically during industrial processes or certain biological routes, have posed a great threat to human health. Particularly during the current COVID-19 pandemic, effective filtration of the virus is an urgent matter worldwide. In this review, we first introduce some fundamentals about PM, including its source and classification, filtration mechanisms, and evaluation parameters. Advanced filtration materials and their functions are then summarized, among which polymers and MOFs are discussed in detail together with their antibacterial performance. The discussion on the application is divided into end-of-pipe treatment and source control. Finally, we conclude this review with our prospective view on future research in this area. Graphical Image 1

Female reproductive health during the COVID-19 pandemic: latest evidence and understanding.

PURPOSE: The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has imposed a heavy burden on medical systems. In addition to the respiratory system, the virus also causes injuries to other organs and systems such as the gastroenteric system, kidneys, and reproductive system. Female reproductive health requires more attention in this context. METHODS: We have performed a thorough review of the relevant literature that addresses the impacts of SARS-CoV-2 infection and COVID-19 vaccination on the female reproductive system. RESULTS: Most evidence shows that SARS-CoV-2 does not infect the female reproductive system. However, the virus may indirectly influence sex hormone concentrations through inflammation associated with cytokine storms and nervous system damage. Menstrual disorders in women infected with SARS-CoV-2 may be caused by down-regulation of angiotensin-converting enzyme 2, abnormal hormone levels, medications, and stress. There is no significant difference in ovarian follicle quality and in vitro fertilization parameters between the pre- and post-COVID-19 vaccination groups. In addition, most symptoms due to side effects of vaccination could recover within a short period of time. CONCLUSION: SARS-CoV-2 infection affects female reproductive system function through multiple mechanisms. It is recommended that women of childbearing age be vaccinated with COVID-19 vaccine.

Vaccine inequity-induced COVID-19 dilemma: Time to sober up.

UNSTRUCTURED: The ongoing coronavirus disease 2019 pandemic has not only posed a serious threat to public health but has also imposed a heavy burden on medical systems and global economies. To combat this challenge, unprecedented efforts have been made by governments and the scientific community in the development and production of vaccines. As a result, less than a year elapsed between identification of a novel pathogen sequence and large-scale vaccine rollout. However, much of the focus and debate has increasingly shifted to the looming risk of global vaccine inequity and whether we could do more to modify this risk. In this paper, we first outline the scope of inequitable vaccine distribution and identify its truly catastrophic consequences. Then, from the perspectives of political will, free markets and profit-driven enterprises based on patent and intellectual property protection, we analyze in-depth the root causes why this phenomenon is so difficult to combat. Apart from these, some specific and crucial solutions that should be undertaken in the long term were also put forward, in order to provide a useful reference for the authorities, stakeholders and researchers involved in addressing this global crisis and the next one.

Advances in particulate matter filtration: materials, performance, and application

Air-borne pollutants in particulate matter (PM) form, produced either physically during industrial processes or certain biological routes, have posed a great threat to human health. Particularly during the current COVID-19 pandemic, effective filtration of the virus is an urgent matter worldwide. In this review, we first introduce some fundamentals about PM, including its source and classification, filtration mechanisms, and evaluation parameters. Advanced filtration materials and their functions are then summarized, among which polymers and MOFs are discussed in detail together with their antibacterial performance. The discussion on the application is divided into end-of-pipe treatment and source control. Finally, we conclude this review with our prospective view on future research in this area.

Impact of the COVID-19 pandemic on air pollution in Chinese megacities from the perspective of traffic volume and meteorological factors.

During 2020, the COVID-19 pandemic resulted in a widespread lockdown in many cities in China. In this study, we assessed the impact of changes in human activities on air quality during the COVID-19 pandemic by determining the relationships between air quality, traffic volume, and meteorological conditions. The megacities of Wuhan, Beijing, Shanghai, and Guangzhou were selected as the study area, and the variation trends of air pollutants for the period January-May between 2016 and 2020 were analyzed. The passenger volume of public transportation (PVPT) and the passenger volume of taxis (PVT) along with data on precipitation, temperature, relative humidity, wind speed, and boundary layer height were used to identify and quantify the driving force of the air pollution variation. The results showed that the change rates of fine particulate matter (PM2.5), NO2, and SO2 before and during the lockdown in the four megacities ranged from -49.9% to 78.2% (average: -9.4% ± 59.3%), -55.4% to -32.3% (average: -43.0% ± 9.7%), and - 21.1% to 11.9% (average: -10.9% ± 15.4%), respectively. The response of NO2 to the lockdown was the most sensitive, while the response of PM2.5 was smaller and more delayed. During the lockdown period, haze from uninterrupted industrial emissions and fireworks under the effect of air mass transport from surrounding areas and adverse climate conditions was probably the cause of abnormally high PM2.5 concentrations in Beijing. In addition, the PVT was the most significant factor for NO2, and meteorology had a greater impact on PM2.5 than NO2 and SO2. There is a need for more national-level policies for limiting firework displays and traffic emissions, as well as further studies on the formation and transmission of secondary air pollutants.