Distributed probability of infection risk of airborne respiratory diseases

2021 ◽  
pp. 1420326X2110303
Author(s):  
Zhiqiang (John) Zhai ◽  
He Li
Keyword(s):  
Spatial Distribution ◽  
Respiratory Diseases ◽  
Infection Risk ◽  
Mitigation Measures ◽  
Critical Parameters ◽  
Lecture Hall ◽  
Potential Health ◽  
Air Cleaners ◽  
Air Mixing ◽  
Mean Risk

Infection risk is commonly used to predict potential health impacts of airborne respiratory diseases such as ‘severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)' and associated environment conditions and mitigation measures. The assumption of perfect air-mixing in spaces is widely applied in prediction, which projects a single mean risk of infection in the space. Detailed distribution of infection risk, especially for large spaces such as large lecture hall, indoor stadium and ballroom, will be highly desired for evaluating indoor risks and improvement performance of mitigating strategies. This study developed new formulae for calculating the spatial distribution of infection risk, stemming from the original Wells–Riley model but integrating the spatial distribution of pathogen concentrations. Case studies were presented for two typical large public spaces (i.e. restaurant and ballroom). Distributed infection risks were predicted with and without mitigation measures, upon which critical parameters of portable air cleaners can be optimized. The method can be employed for estimating local infection risks of airborne respiratory diseases using either measured or simulated pathogen concentration.

Spatial distribution, mobility and potential health risks of arsenic and lead concentrations in semiarid fine top-soils of Durango City, Mexico

CATENA ◽  
2020 ◽  
Vol 190 ◽  
pp. 104540 ◽  
Author(s):  
Fabiola S. Sosa-Rodríguez ◽  
Jorge Vazquez-Arenas ◽  
Patricia Ponce Peña ◽  
Miguel A. Escobedo-Bretado ◽  
Francisco X. Castellanos-Juárez ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Health Risks ◽  
Potential Health

scholarly journals Environment and Health in Contaminated Sites: The Case of Taranto, Italy

2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
Roberta Pirastu ◽  
Pietro Comba ◽  
Ivano Iavarone ◽  
Amerigo Zona ◽  
Susanna Conti ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Respiratory Diseases ◽  
Health Indicators ◽  
Industrial Area ◽  
Contaminated Sites ◽  
Cardiovascular Risk Reduction ◽  
Potential Health ◽  
Environment And Health ◽  
National Priority ◽  
Study Results

The National Environmental Remediation programme in Italy includes sites with documented contamination and associated potential health impacts (National Priority Contaminated Sites—NPCSs). SENTIERI Project, an extensive investigation of mortality in 44 NPCSs, considered the area of Taranto, a NPCS where a number of polluting sources are present. Health indicators available at municipality level were analyzed, that is, mortality (2003–2009), mortality time trend (1980–2008), and cancer incidence (2006-2007). In addition, the cohort of individuals living in the area was followed up to evaluate mortality (1998–2008) and morbidity (1998–2010) by district of residence. The results of the study consistently showed excess risks for a number of causes of death in both genders, among them: all causes, all cancers, lung cancer, and cardiovascular and respiratory diseases, both acute and chronic. An increased infant mortality was also observed from the time trends analysis. Mortality/morbidity excesses were detected in residents living in districts near the industrial area, for several disorders including cancer, cardiovascular, and respiratory diseases. These coherent findings from different epidemiological approaches corroborate the need to promptly proceed with environmental cleanup interventions. Most diseases showing an increase in Taranto NPCS have a multifactorial etiology, and preventive measures of proven efficacy (e.g., smoking cessation and cardiovascular risk reduction programs, breast cancer screening) should be planned. The study results and public health actions are to be communicated objectively and transparently so that a climate of confidence and trust between citizens and public institutions is maintained.

Computational Studies on Charge Stratification and Fuel-Air Mixing in a New Two-Stroke Engine

2005 ◽  
Author(s):  
Shamit Bakshi ◽  
T. N. C. Anand ◽  
R. V. Ravikrishna
Keyword(s):  
Initial Conditions ◽  
Computational Study ◽  
Three Dimensional ◽  
The State ◽  
Operating Conditions ◽  
Injection System ◽  
Critical Parameters ◽  
Mixing Process ◽  
Air Mixing ◽  
Stroke Engine

In this paper, detailed computational study is presented which helps to understand and improve the fuel-air mixing in a new direct-mixture-injection two-stroke engine. This new air-assisted injection system-based two-stroke engine is being developed at the Indian Institute of Science, Bangalore over the past few years. It shows the potential to meet emission norms such as EURO-II and EURO-III and also deliver satisfactory performance. This work proposes a comprehensive strategy to study the air-fuel mixing process in this engine and shows that this strategy can be potentially used to improve the engine performance. A three-dimensional compressible flow code with standard k–ε turbulence model with wall functions is developed and used for this modeling. To account for the moving boundary or piston in the engine cylinder domain, a non-stationary and deforming grid is used in this region with stationary cells in the ports and connecting ducts. A flux conservation scheme is used in the domain interface to allow the in-cylinder moving mesh to slide past the fixed port meshes. The initial conditions for flow parameters are taken from the output of a three-dimensional scavenging simulation. The state of the inlet charge is obtained from a separate modeling of the air-assisted injection system of this engine. The simulation results show that a large, near-stoichiometric region is present at most operating conditions in the cylinder head plane. The state of the in-cylinder charge at the onset of ignition is studied leading to a good understanding of the mixing process. In addition, sensitivity of two critical parameters on the mixing and stratification is investigated. The suggested parameters substantially enhance the flammable proportion at the onset of combustion. The predicted P–θ from a combustion simulation supports this recommendation.

Spatial distribution and potential health risks of heavy metal(loid)s present in drinking water resources of Iran

2020 ◽  
Vol 179 ◽  
pp. 223-241
Author(s):  
Kamaladdin Karimyan ◽  
Mahmood Alimohammadi ◽  
Afshin Maleki ◽  
Masud Yunesian ◽  
Ramin Nabizadeh Nodehi ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Drinking Water ◽  
Spatial Distribution ◽  
Water Resources ◽  
Health Risks ◽  
Potential Health ◽  
Drinking Water Resources

Spatial distribution of infection risk of SARS transmission in a hospital ward

2009 ◽  
Vol 44 (8) ◽  
pp. 1651-1658 ◽  
Author(s):  
Hua Qian ◽  
Yuguo Li ◽  
Peter V. Nielsen ◽  
Xinhua Huang
Keyword(s):  
Spatial Distribution ◽  
Infection Risk ◽  
Hospital Ward

Computational investigation of combustion instabilities in an air heater with a new computational model

2021 ◽  
pp. 1-26
Author(s):  
L. Yuan ◽  
C. Shen
Keyword(s):  
Spatial Distribution ◽  
Computational Model ◽  
Heat Release ◽  
Longitudinal Mode ◽  
Critical Parameters ◽  
Combustion Instabilities ◽  
Mean Flow ◽  
Air Heater ◽  
Longitudinal Modes ◽  
Design Values

Abstract On the basis of air heater characteristics, a new computational model was developed in this paper, which was aimed at investigating acoustics and instabilities in air heaters. This model included the effects of mean flow, viscosity, entropy waves, non-linear acoustics and realistic boundary conditions. In addition, it was practical for air heaters with hundreds of injectors, complex configurations and geometries. Analytical solutions of acoustics in a closed rectangular cavity were used to verify and validate the computational model. It was shown that the predicted critical parameters of air heater agreed well with the experimental data or design values. This model predicted the self-excited spinning tangential modes without any preliminary assumptions about them. Traditional combustion response function assumes that combustion mainly takes place in a so-called rapid combustion zone, and this zone is usually modelled as a disc in the combustor near the injection head. However, in practice, the flame has a spatial distribution. This paper described the effect of flame spatial distribution on predictions of oscillation frequency and mode. It was found that frequency and mode shape of oscillations closely depended on the length of the heat release zone. Comparison of different heat release zones indicated that the increment of heat release length exhibited an increased tendency toward lower-order longitudinal modes, when the heat release zone was located near the faceplate where it was the pressure antinode of the longitudinal mode. Modulation of heat release length might cause bifurcations between standing and turning modes. A noticeable tendency was toward higher-order standing tangential mode with increasing heat release length. Finally, theoretical analysis of the modal behaviour, i.e. standing or spinning waves, was performed.

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