Environmental factors and the epidemics of COVID-19

COVID-19 multiwaves as multiphase percolation: a general N-sigmoidal equation to model the spread

Abstract

The aim of the current study is to investigate the spread of the COVID-19 pandemic as a multiphase percolation process. Mathematical equations have been developed to describe the time dependence of the number of cumulative infected individuals, I t , and the velocity of the pandemic, V p t , as well as to calculate epidemiological characteristics. The study focuses on the use of sigmoidal growth models to investigate multiwave COVID-19. Hill, logistic dose response and sigmoid Boltzmann models fitted successfully a pandemic wave. The sigmoid Boltzmann model and the dose response model were found to be effective in fitting the cumulative number of COVID-19 cases over time 2 waves spread (N = 2). However, for multiwave spread (N > 2), the dose response model was found to be more suitable due to its ability to overcome convergence issues. The spread of N successive waves has also been described as multiphase percolation with a period of pandemic relaxation between two successive waves.

Graphical abstract

Borderline microscopic organism and lockdown impacted across the borders-global shakers

Viruses are the potential cause of several diseases including novel corona virus-19, flu, small pox, chicken pox, acquired immunodeficiency syndrome, severe acute respiratory syndrome etc. The objectives of this review article are to summarize the reasons behind the epidemics caused by several emerging viruses and bacteria, how to control the infection and preventive strategies. We have explained the causes of epidemics along with their preventive measures, the impact of lockdown on the health of people and the economy of a country. Several reports have revealed the transmission of infection during epidemic from the contact of an infected person to the public that can be prevented by implementing the lockdown by the government of a country. Though lockdown has been considered as one of the significant parameters to control the diseases, however, it has some negative consequences on the health of people as they can be more prone to other ailments like obesity, diabetes, cardiac problems etc. and drastic decline in the economy of a country. Therefore, the transmission of diseases can be prevented by warning the people about the severity of diseases, avoiding their public transportation, keeping themselves isolated, strictly following the guidelines of lockdown and encouraging regular exercise.

Airborne concentrations of SARS-CoV-2 in indoor community environments in Italy

COVID-19 pandemic raised a debate regarding the role of airborne transmission. Information regarding virus-laden aerosol concentrations is still scarce in community indoors and what are the risks for general public and the efficiency of restriction policies. This work investigates, for the first time in Italy, the presence of SARS-CoV-2 RNA in air samples collected in different community indoors (one train station, two food markets, one canteen, one shopping centre, one hair salon, and one pharmacy) in three Italian cities: metropolitan city of Venice (NE of Italy), Bologna (central Italy), and Lecce (SE of Italy). Air samples were collected during the maximum spread of the second wave of pandemic in Italy (November and December 2020). All collected samples tested negative for the presence of SARS-CoV-2, using both real-time RT-PCR and ddPCR, and no significant differences were observed comparing samples taken with and without customers. Modelling average concentrations, using influx of customers' data and local epidemiological information, indicated low values (i.e. < 0.8 copies m-3 when cotton facemasks are used and even lower for surgical facemasks). The results, even if with some limitations, suggest that the restrictive policies enforced could effectively reduce the risk of airborne transmissions in the community indoor investigated, providing that physical distance is respected.

Nonlinearity in the relationship between COVID-19 cases and carbon damages: controlling financial development, green energy, and R&D expenditures for shared prosperity

The world faces a high alert of coronavirus disease 2019 (COVID-19), leading to a million deaths and could become infected to reach a billion numbers. A sizeable amount of scholarly work has been available on different aspects of social-economic and environmental factors. At the same time, many of these studies found the linear (direct) causation between the stated factors. In many cases, the direct relationship is not apparent. The world is unsure about the possible determining factors of the COVID-19 pandemic, which need to be known through conducting nonlinearity (indirect) relationships, which caused the pandemic crisis. The study examined the nonlinear relationship between COVID-19 cases and carbon damages, managing financial development, renewable energy consumption, and innovative capability in a cross section of 65 countries. The results show that inbound foreign direct investment first increases and later decreases because of the increasing coronavirus cases. Further, the rise and fall in the research and development expenditures and population density exhibits increasing coronavirus cases across countries. The continued economic growth initial decreases later increase by adopting standardized operating procedures to contain coronavirus disease. The inter-temporal relationship shows that green energy source and carbon damages would likely influence the coronavirus cases with a variance of 17.127% and 5.440%, respectively, over a time horizon. The policymakers should be carefully designing sustainable healthcare policies, as the cost of carbon emissions leads to severe healthcare issues, which are likely to get exposed to contagious diseases, including COVID-19. The sustainable policy instruments, including renewable fuels in industrial production, advancement in cleaner production technologies, the imposition of carbon taxes on dirty production, and environmental certifications, are a few possible remedies that achieve healthcare sustainability agenda globally.