Heat Wave and Bushfire Meteorology in New South Wales, Australia: Air Quality and Health Impacts.

The depletion of air quality is a major problem that is faced around the globe. In Australia, the pollutants emitted by bushfires play an important role in making the air polluted. These pollutants in the air result in many adverse impacts on the environment. This paper analysed the air pollution from the bushfires from November 2019 to July 2020 and identified how it affects the human respiratory system. The bush fires burnt over 13 million hectares, destroying over 2400 buildings. While these immediate effects were devastating, the long-term effects were just as devastating, with air pollution causing thousands of people to be admitted to hospitals and emergency departments because of respiratory complications. The pollutant that caused most of the health effects throughout Australia was Particulate Matter (PM) PM2.5 and PM10. Data collection and analysis were covered in this paper to illustrate where and when PM2.5 and PM10, and other pollutants were at their most concerning levels. Susceptible areas were identified by analysing environmental factors such as temperature and wind speed. The study identified how these pollutants in the air vary from region to region in the same time interval. This study also focused on how these pollutant distributions vary according to the temperature, which helps to determine the relationship between the heatwave and air quality. A computational model for PM2.5 aerosol transport to the realistic airways was also developed to understand the bushfire exhaust aerosol transport and deposition in airways. This study would improve the knowledge of the heat wave and bushfire meteorology and corresponding respiratory health impacts.

Biomedical and biophysical limits to mathematical modeling of pulmonary system mechanics: a scoping review on aerosol and drug delivery.

Undoubtedly, the construction of the biomechanical geometry systems with the help of computer tomography (CT) and magnetic resonance imaging (MRI) has made a significant advancement in studying in vitro numerical models as accurately as possible. However, some simplifying assumptions in the computational studies of the respiratory system have caused errors and deviations from the in vivo actual state. The most important of these hypotheses is how to generate volume from the point cloud exported from CT or MRI images, not paying attention to the wall thickness and its effect in computational fluid dynamic method, statistical logic of aerosol trap in software; and most importantly, the viscoelastic effect of respiratory tract wall in living tissue pointed in the fluid-structure interaction method. So that applying the viscoelastic dynamic mesh effect in the form of the moving deforming mesh can be very effective in achieving more appropriate response quality. Also, changing the volume fraction of the pulmonary extracellular matrix constituents leads to changes in elastic modulus (storage modulus) and the viscous modulus (loss modulus) of lung tissue. Therefore, in the biomedical computational methods where the model wall is considered flexible, the viscoelastic properties of the texture must be considered correctly.

SARS-CoV-2 droplet deposition path and its effects on the human upper airway in the oral inhalation.

BACKGROUND AND OBJECTIVE: It is crucial to study the uptake of viral droplets in the human respiratory system to control, prevent, and treat diseases. METHODS: In this study, a well-verified real anatomical model was used; the passage of air in the human upper respiratory system computed using high-quality Computer Tomography (CT) images. Then, the airflow field, along with the coronavirus micro-droplets injection, was examined in this realistic model using the Fluid-Structure Interaction (FSI) method. The Discrete Phase Model (DPM) was used to solve the field, and with the help of it, the accurate assessment of the temporal and spatial motion of the deposition in the virus-impregnated droplets was obtained in vitro in the upper respiratory system. RESULTS: The results show that the amount of deposited micro-droplets in the nasal cavity area is meager at the inhalation only through the oral. However, it has the most residence time in this area. The most and least droplet absorption occurred in the oral cavity and larynx-trachea, respectively. Deposition efficiency is about 100% in 30 L/min flow rate and 10 µm diameter; in other words, no droplet enters the lungs. This study's other achievements include the relatively inverse relationship between droplets deposition efficiency in some parts of the upper airway, which have the most deformation in the tract. CONCLUSIONS: Utilization of a realistic model with accurate and precise computational analysis can end speculation about the deposition zone, accumulation, and the effects of the COVID-19 virus on the upper respiratory tract. On the other hand, recognizing the virus-containing droplet location can ease understanding the areas where the virus can first infect in the upper respiratory tract.