SARS-CoV-2 infection (COVID-19) in children.

Since the outbreak in December 2019, the SARS-CoV-2 pandemic virus has been a major public health problem in all countries of the world. The virus is transmitted by inhalation of respiratory droplets from the patient or asymptomatic carrier and is highly contagious. The clinical disease in children is similar to any acute respiratory infection with predominant upper respiratory symptoms, but occasionally can progress to pneumonia with acute respiratory distress syndrome and multiorgan failure. The disease is milder in children than in adults, with low mortality, and it appears that infants and young children have a somewhat more severe clinical course. Diagnosis is made by detecting the virus from respiratory samples (mainly nasopharyngeal and oropharyngeal swabs) using polymerase chain reaction. Treatment is usually symptomatic, and in severe and critical forms, the use of one of the antiviral drugs (lopinavir-ritonavir, remdesivir, hydroxychloroquine) may be consideredCopyright © 2020 Croatian Paediatric Society. All rights reserved.

Association between measured air pollution levels in the troposphere and surface air with COVID-19 hospitalization in Tomsk, Russia, 2022

The results of a preliminary analysis of the relationship between the short-term impact of air pollution exposure on hospitalizations associated with COVID-19 in Tomsk, Russia are presented. The statistical data on air pollution and COVID-19 associated hospitalization were collected and analyzed for the period from March 16, 2022 to April 14, 2022. This period corresponds to a flat plateau of confirmed COVID-19 cases after the main pandemic wave in 2022 in Tomsk and the Tomsk region which were associated with omicron strain of SARS-CoV-2. It was found that all representative peaks in a graph of daily hospitalizations coincide with the peaks in graphs of measured levels of air pollution. The increase in hospitalizations occurred on the same days when air pollution levels increased, or with a slight lag of 1-2 days. This allows us to tentatively conclude that air pollution has a quick effect on infected persons and may provoke an increase in symptoms and severity of the disease. Further detailed research is required. © 2022 SPIE.

A Computational Approach for the Characterization of Airborne Pathogen Transmission in Turbulent Molecular Communication Channels

Airborne pathogen transmission mechanisms play a key role in the spread of infectious diseases such as COVID-19. In this work, we propose a computational fluid dynamics (CFD) approach to model and statistically characterize airborne pathogen transmission via pathogen-laden particles in turbulent channels from a molecular communication viewpoint. To this end, turbulent flows induced by coughing and the turbulent dispersion of droplets and aerosols are modeled by using the Reynolds-averaged Navier-Stokes equations coupled with the realizable k-model and the discrete random walk model, respectively. Via simulations realized by a CFD simulator, statistical data for the number of received particles are obtained. These data are post-processed to obtain the statistical characterization of the turbulent effect in the reception and to derive the probability of infection. Our results reveal that the turbulence has an irregular effect on the probability of infection, which shows itself by the multi-modal distribution as a weighted sum of normal and Weibull distributions. Furthermore, it is shown that the turbulent MC channel is characterized via multi-modal, i.e., sum of weighted normal distributions, or stable distributions, depending on the air velocity. Crown

Soft Ionization: Improving Indoor Air Quality

In this paper we report two applications of a subcategory of air cleaning devices based on soft ionization that do not cause molecular fragmentation. A system that includes two unipolar ionizing modules has been used to simultaneously produce positive and negative ions in the air. In one set of experiments a large chamber (28 m3) was used to study the effect of ions on reducing PM1.0 particles produced by a research grade calibrated cigarette. The data presented in this paper were obtained using a carbon-brush-based bipolar ionizer and a MERV 10 filter with electret media in a recirculating HVAC system. Significant improvement in removal rate of fine and ultrafine particles was achieved when using the bipolar ionizer in conjunction with the MERV 10 filter. The second set of experiments were conducted using a 36 m3 chamber, following BSL-3 standards, to study the effect of ions on aerosolized SARS-CoV-2. Results of these investigations reveal the inactivation rate of SARS-CoV-2 are enhanced when ions are introduced in the air;inactivation rates were increased by more than 60%and 90%for ion densities of 10,000/cc and 18,000/cc. IEEE

Inhalation Vaccine Development

Numerous advantages to inhalation vaccines Vaccines delivered via inhalation enable targeting of the respiratory tract mucosa and generation of both humoral and cell-mediated immunity, according to Pierre A. Morgon, executive vice president. [...]inhaled vaccines delivered as liquids using nebulizers can potentially be administered with lower requirement for extensive healthcare infrastructure or as many trained healthcare personnel within an immunization centre (2). Researchers at McMaster University, for instance, have shown inhalation of a tuberculosis vaccine to be more effective than delivery via nasal sprays, because the vaccine penetrates much deeper into the airway (8). Because inhaled vaccines provide local immunity to the respiratory tract, they are seen to be ideal solutions for interrupting the spread of viruses with high transmission rates and the potential to lead to global pandemics (9). Beyond these two approaches, there are inhalation vaccines under development based on attenuated influenza virus, parainfluenza virus (PIV) 5, lentiviruses, Newcastle disease virus (NDV), and vesicular stomatitis virus (VSV);bacterium vectors, nucleic acids (messenger RNA, DNA), and protein subunits (3).

Surgical plume and its associated hazards to perioperative staff: A review of current standards for practice and risk management

Surgical plume poses a risk to perioperative nurses and the perioperative team as a whole, as well as the operative patient. Surgical plume contains various hazardous components which pose multiple health risks to the perioperative staff who are exposed to it. Further research is required in order to definitively understand the risks to perioperative staff from long-term exposure to surgical plume and to advance current policies and procedures. The current practice standard on surgical plume management from the Australian College of Perioperative Nurses (ACORN) sets out methods of reducing these risks. However, this standard's utility in practice and barriers to its implementation lead to ongoing unnecessary plume exposure. Through adhering to current practice standards and educating perioperative nurses, the risks posed by surgical plume can be mitigated. Thorough education on this topic will empower nurses to advocate for their safety and the safety of their patients, leading to the reduction of surgical plume exposure.

A COMPARISON OF TWO APPROACHES TO SCREEN THE FILTRATION PROPERTIES OF MATERIALS DURING THE COVID-19 EMERGENCY TIME

Determination of the filtration efficiency (even to nanosize) of several textiles was carried out during emergency time at the beginning of the COVID-19 pandemic lockdown in order to perform a fast screening of materials candidate for facial masks. At this purpose, a double strategy was adopted in Milan: scanning electron microscopy investigation and a classical filtration test of ambient aerosol. The latter was used in order to mimic as much as possible the capability to filter ambient aerosol that might contain COVID-19. The two methods were compared to investigate their capability to identify only textiles characterized by a filtration efficiency higher than 90% (thus candidate for facial mask production). Results showed filtration efficiency above 90% for promising candidate textiles as well as poor filtration capabilities (below 60%) of other textiles, enabling a fast screening of the materials from different Italian factories.

Can aerosols-generating dental, oral and maxillofacial, and orthopedic surgical procedures lead to disease transmission? An implication on the current COVID-19 pandemic.

Various dental, maxillofacial, and orthopedic surgical procedures (DMOSP) have been known to produce bioaerosols, that can lead to the transmission of various infectious diseases. Hence, a systematic review (SR) aimed at generating evidence of aerosols generating DMOSP that can result in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), further investigating their infectivity and assessing the role of enhanced personal protective equipment (PPE) an essential to preventing the spreading of SARS-CoV-2 during aerosol-generating procedures (AGPs). This SR was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA) guidelines based on a well-designed Population, Intervention, Comparison, Outcomes and Study (PICOS) framework, and various databases were searched to retrieve the studies which assessed potential aerosolization during DMOSP. This SR included 80 studies (59 dental and 21 orthopedic) with 7 SR, 47 humans, 5 cadaveric, 16 experimental, and 5 animal studies that confirmed the generation of small-sized < 5 µm particles in DMOSP. One study confirmed that HIV could be transmitted by aerosolized blood generated by an electric saw and bur. There is sufficient evidence that DMOSP generates an ample amount of bioaerosols, but the infectivity of these bioaerosols to transmit diseases like SARS-CoV-2 generates very weak evidence but still, this should be considered. Confirmation through isolation and culture of viable virus in the clinical environment should be pursued. An evidence provided by the current review was gathered by extrapolation from available experimental and empirical evidence not based on SARS-CoV-2. The results of the present review, therefore, should be interpreted with great caution.

Ventilation strategies based on an aerodynamic analysis during a large-scale SARS-CoV-2 outbreak in an acute-care hospital.

BACKGROUND: This study aimed to investigate ventilation strategies to prevent nosocomial transmission of coronavirus disease 2019 (COVID-19). METHODS: We conducted a retrospective epidemiological investigation of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak in a teaching hospital (February-March 2021). The largest outbreak ward was studied, and measurements were taken to determine the pressure difference and air change per hour (ACH) of the rooms. Airflow dynamics were assessed using an oil droplet generator, indoor air quality sensor, and particle image velocimetry in the index patient's room, corridor, and opposite rooms, by varying the opening and closing of windows and doors. RESULTS: During the outbreak, 283 COVID-19 cases were identified. The SARS-CoV-2 spread occurred sequentially from the index room to the nearest room, especially the opposite. The aerodynamic study demonstrated that droplet-like particles in the index room diffused through the corridor and the opposite room through the opening door. The mean ACH of the rooms was 1.44; the air supply volume was 15.9% larger than the exhaust volume, forming a positive pressure. Closing the door prevented diffusion between adjacent rooms facing each other, and natural ventilation reduced the concentration of particles within the ward and minimised their spread to adjacent rooms. CONCLUSIONS: Spread of droplet-like particles between rooms could be attributed to the pressure difference between the rooms and corridor. To prevent spread of SARS-CoV-2 between rooms, increasing the ACH in the room by maximising ventilation and minimising the positive pressure through supply/exhaust control and closing the room door are essential.

Mitigation of Respirable Aerosol Particles from Speech and Language Therapy Exercises.

INTRODUCTION: Phonation and speech are known sources of respirable aerosol in humans. Voice assessment and treatment manipulate all the subsystems of voice production, and previous work (Saccente-Kennedy et al., 2022) has demonstrated such activities can generate >10 times more aerosol than conversational speech and 30 times more aerosol than breathing. Aspects of voice therapy may therefore be considered aerosol generating procedures and pose a greater risk of potential airborne pathogen (eg, SARS-CoV-2) transmission than typical speech. Effective mitigation measures may be required to ensure safe service delivery for therapist and patient. OBJECTIVE: To assess the effectiveness of mitigation measures in reducing detectable respirable aerosol produced by voice assessment/therapy. METHODS: We recruited 15 healthy participants (8 cis-males, 7 cis-females), 9 of whom were voice-specialist speech-language pathologists. Optical Particle Sizers (OPS) (Model 3330, TSI) were used to measure the number concentration of respirable aerosol particles (0.3 µm-10 µm) generated during a selection of voice assessment/therapy tasks, both with and without mitigation measures in place. Measurements were performed in a laminar flow operating theatre, with near-zero background aerosol concentration, allowing us to quantify the number concentration of respiratory aerosol particles produced. Mitigation measures included the wearing of Type IIR fluid resistant surgical masks, wrapping the same masks around the end of straws, and the use of heat and moisture exchange microbiological filters (HMEFs) for a water resistance therapy (WRT) task. RESULTS: All unmitigated therapy tasks produced more aerosol than unmasked breathing or speaking. Mitigation strategies reduced detectable aerosol from all tasks to a level significantly below, or no different to, that of unmasked breathing. Pooled filtration efficiencies determined that Type IIR surgical masks reduced detectable aerosol by 90%. Surgical masks wrapped around straws reduced detectable aerosol by 96%. HMEF filters were 100% effective in mitigating the aerosol from WRT, the exercise that generated more aerosol than any other task in the unmitigated condition. CONCLUSIONS: Voice therapy and assessment causes the release of significant quantities of respirable aerosol. However, simple mitigation strategies can reduce emitted aerosol concentrations to levels comparable to unmasked breathing.

Different approaches to explore the impact of COVID-19 lockdowns on carbonaceous aerosols at a European rural background site.

To prevent the fast spread of COVID-19, worldwide restrictions have been put in place, leading to a reduction in emissions from most anthropogenic sources. In this study, the impact of COVID-19 lockdowns on elemental (EC) and organic (OC) carbon was explored at a European rural background site combining different approaches: - "Horizontal approach (HA)" consists of comparing concentrations of pollutants measured at 4 m a.g.l. during pre-COVID period (2017-2019) to those measured during COVID period (2020-2021); - "Vertical approach (VA)" consists of inspecting the relationship between OC and EC measured at 4 m and those on top (230 m) of a 250 m-tall tower in Czech Republic. The HA showed that the lockdowns did not systematically result in lower concentrations of both carbonaceous fractions unlike NO2 (25 to 36 % lower) and SO2 (10 to 45 % lower). EC was generally lower during the lockdowns (up to 35 %), likely attributed to the traffic restrictions whereas increased OC (up to 50 %) could be attributed to enhanced emissions from the domestic heating and biomass burning during this stay-home period, but also to the enhanced concentration of SOC (up to 98 %). EC and OC were generally higher at 4 m suggesting a greater influence of local sources near the surface. Interestingly, the VA revealed a significantly enhanced correlation between EC and OC measured at 4 m and those at 230 m (R values up to 0.88 and 0.70 during lockdown 1 and 2, respectively), suggesting a stronger influence of aged and long distance transported aerosols during the lockdowns. This study reveals that lockdowns did not necessarily affect aerosol absolute concentrations but it certainly influenced their vertical distribution. Therefore, analyzing the vertical distribution can allow a better characterization of aerosol properties and sources at rural background sites, especially during a period of significantly reduced human activities.

Characteristics and sources of carbonaceous aerosols in a semi-arid city: Quantifying anthropogenic and meteorological impacts.

Carbonaceous aerosols have great adverse impacts on air quality, human health, and climate. However, there is a limited understanding of carbonaceous aerosols in semi-arid areas. The correlation between carbonaceous aerosols and control measures is still unclear owing to the insufficient information regarding meteorological contribution. To reveal the complex relationship between control measures and carbonaceous aerosols, offline and online observations of carbonaceous aerosols were conducted from October 8, 2019 to October 7, 2020 in Hohhot, a semi-arid city. The characteristics and sources of carbonaceous aerosols and impacts of anthropogenic emissions and meteorological conditions were studied. The annual mean concentrations (± standard deviation) of fine particulate matter (PM2.5), organic carbon (OC), and elemental carbon (EC) were 42.81 (±40.13), 7.57 (±6.43), and 2.25 (±1.39) µg m-3, respectively. The highest PM2.5 and carbonaceous aerosol concentrations were observed in winter, whereas the lowest was observed in summer. The result indicated that coal combustion for heating had a critical role in air quality degradation in Hohhot. A boost regression tree model was applied to quantify the impacts of anthropogenic emissions and meteorological conditions on carbonaceous aerosols. The results suggested that the anthropogenic contributions of PM2.5, OC, and EC during the COVID-19 lockdown period were 53.0, 15.0, and 2.36 µg m-3, respectively, while the meteorological contributions were 5.38, 2.49, and -0.62 µg m-3, respectively. Secondary formation caused by unfavorable meteorological conditions offset the emission reduction during the COVID-19 lockdown period. Coal combustion (46.4% for OC and 35.4% for EC) and vehicular emissions (32.0% for OC and 50.4% for EC) were the predominant contributors of carbonaceous aerosols. The result indicated that Hohhot must regulate coal use and vehicle emissions to reduce carbonaceous aerosol pollution. This study provides new insights and a comprehensive understanding of the complex relationships between control strategies, meteorological conditions, and air quality.

Insisting with mask or demanding for more: Plights of the transmission of airborne diseases

Airborne transmission is worldwide popular topic with numerous discussion and researches since influenza pandemic could cost the global economy a lot. In this part of research, we mainly focus on the mechanisms of airborne transmission, together with some determinant factors that influence the spread of aerosols like temperature, humidity and particle size. Finally with several existed cases, insisting masks wearing, especially with three-layer masks wearing are necessary in nowadays for efficiently preventing the transmission of airborne diseases up to 90%. Other possible infection control measures like 2m social distancing are also needed as hygiene measures. © 2023 SPIE.

Effects of various respiratory activities on human aerosol emissions: experimental design and preliminary results

This study combines particle measurements and acoustic measurements to study aerosols generated in breathing, speaking, singing and coughing. Particle measurements are carried out using a portable measurement chamber designed specially for the study. Acoustic measurements of voice production are conduced to standardize measurements in human aerosol emission and to reveal possible reasons for the individual differences in particle generation. Understanding mechanisms of human aerosol generation is important in trying to understand how the airborne transmission of pathogens takes place and furthermore in assessing how to minimize the risk of transmission. The results can be used in the context of all airborne diseases. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.

Knowledge, attitude, and practice towards COVID-19 among students in Kirkuk Medical College, Iraq

On March 11, 2020, the World Health Organization (WHO) designated the new coronavirus COVID-19 to be epidemic. Adherence to infection control methods is strongly affected by an individual's knowledge, attitudes, and practices (KAP). The study aimed to evaluate medical students' understanding, and attitudes toward COVID-19 at the Kirkuk Medical College in Iraq. From October 16 to October 26, 2020, a cross-sectional online study was conducted, among a sample of students in Kirkuk Medical College, one of the Iraqi governorates. A total of 214 students were included in this research, and the age varied between 20-25 years. The questionnaire was divided into demographic data, knowledge, attitudes, and practices, modified from an online questionnaire regarding COVID-19 previously used. Descriptive statistics and t-tests were conducted. Among the study sample (n=214), age ranged between 20-25 years, 72.9% were females, and 86.9% resided in urban areas. The learning questionnaire's total accuracy rate was 96.3%. 98.1% of the students know that the virus is spreading by respiratory droplets from infected individuals, 30.4% have a good attitude towards COVID-19, and 100% have good practice dodging crowded places and practicing appropriate hand hygiene. The majority of students are knowledgeable of disease transference prevention and good practices. Female gender and urban residency play a positive role in knowledge and practice in respect to COVID-19 but not in what concerns the attitude. It is recommended to continue health education programs to correct the negative attitude among students, especially those who reside in rural areas.Copyright © 2023, Codon Publications. All rights reserved.

SARS-CoV-2 risk assessment for a 30-minute car journey

In this paper a numerical methodology for close proximity exposure (<2m) is applied to the analysis of aerosol airborne dispersion and SARS-CoV-2 potential infection risk during short journeys in passenger cars. It consists of a three-dimensional transient Eulerian-Lagrangian numerical model coupled with a recently proposed SARS-CoV-2 emission approach, using the open-source software OpenFOAM. The numerical tool, validated by Particle Image Velocimetry (PIV), is applied to the simulation of aerosol droplets emitted by a contagious subject in a car cabin during a 30-minute journey and to the integrated risk assessment for SARS-CoV-2 for the other passengers. The effects of different geometrical and thermo-fluid-dynamic influence parameters are investigated, showing that both the position of the infected subject and the ventilation system design affect the amount of virus inhaled and the highest-risk position inside the passenger compartment. Calculated infection risk, for susceptible passengers in the car, can reach values up to 59%. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.

Exploring the effects of ventilation and air-conditioned environments, on droplet and airborne transmission of SARS-COV-2

To assess the implications of air conditioning and ventilation on droplet and airborne transmission of SARS-COV-2, several scientific research databases were searched and cross-referenced. Then, an analysis was conducted on the findings pertinent to interaction between several environmental variables affected by HVAC systems and their effect on Virus transmission. The results suggest that airflow velocity may interfere with the trajectories of large respiratory droplets and aerosols. Lower relative humidity provided suitable conditions for virus survival whereas higher temperatures increased aerosol formation, but were detrimental to virus survival. Suboptimal temperatures and humidity can compromise pathogen filtration functions in the nose, while proper use of HVAC functions can help preserve them. Transmission of SARS-COV-2 is not affected solely by the virus's internal properties. Ambient conditions, whether natural or modified by HVAC systems can have a significant effect on the transmissibility and virulence of both the virus and virus-related sickness. The current infection prevention measures, such as social distancing, need to be revised in certain scenarios where natural ventilation or HVAC systems are involved. This will offer, hopefully, higher protection from infections with SARS-COV-2 and similar pathogens. © 2023 by the authors.

Template for Extended Abstract contributions to INDOOR AIR 2022

This investigation presents results of Computational Fluid Dynamics (CFD) modelling of aerosol behaviour within an arbitrary 'realistic' 100m2 office environment, with dynamic and variable respiratory droplet release profile applied based on published findings (Morawska et al., 2009). A multitude of ventilation strategies and configurations have been applied to the base model to compare the effectiveness of reducing the concentration of suspended aerosols over time. A key finding of the investigation indicates a relatively low sensitivity to increasing outside air percentage, and that the benefit from this strategy is heavily dependent on the in-duct droplet decay factor. The application of local recirculating air filtration systems with MERV-13 filters mounted on occupant desks proved significantly more effectiveness than increasing outside air concentration from 25% to 100% in reducing the quantity of suspended aerosols. This highlights that the ventilation industry should perhaps focus on opportunities to integrate filtration systems into furniture, partitions, cabinetry etc., and that an appliance-based solution may be more beneficial for reducing COVID-19 transmission in buildings (and likely more straightforward) than modifications to central ventilation systems, particularly in the application of refurbishments and retrofits. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.

Presence of SARS-CoV-2 in HEPA Filters of Portable Air Cleaners

A method for determining the presence of SARS-CoV-2 RNA in HEPA filters from portable air cleaners (PACs) have been developed and validated. Herein, a monitoring survey was conducted for 13 weeks in three indoor environments, school, nursery and a household of a socio-sanitary center in Ciudad Real, Spain. In this study, we employed environmental monitoring by RT-PCR of the presence of SARS-CoV-2 in HEPA filters and other surfaces of these indoor spaces for a selective screening in asymptomatic population groups. The aim was to limit outbreaks in an early stage. Only one HEPA filter tested positive in the socio-sanitary center. After analysis by RT-PCR of SARS-CoV-2 in residents and healthcare workers, one worker tested positive. Therefore, this study provides direct evidence of virus-containing aerosols trapped in HEPA filters and the possibility of using these PACs for environmental monitoring of SARS-CoV-2 while they remove airborne aerosols and trap the virus. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.