Study On The Influence Of Air-conditioning On The Distribution Of Particulate Matter In Human Settlement Environment
武汉科技大学, China, People's Republic of
Good indoor air quality is of great significance to human health. To master the influence of indoor relative humidity field on spread particulate matter under air-conditioning, giving out particulate matter under different indoor relative humidity field was explored by combining experiment and CFD simulation. The results show that spreading particle concentration has a strong following to give out relative humidity in the room, and decrease along directs room height. With the increase of relative humidity in the room, particles curdle under acting greater liquid bridging force, leading to a significant increase in concentrated particles in the rest, work and breathing concern of the room. At the same time, studies on PM1 and PM2.5 Show that small particle size particles are more likely to be affected by relative humidity and gather in people's respiratory discussion, and with the increase of indoor relative humidity, people's risk of respiratory and cardiovascular and cerebrovascular diseases also increases.
Study on Simplified Wind Tunnel Platform for Outdoor Wind Environment
College of Biochemical Engineering, Beijing Union University
One of the key concerns in architecture design and regional planning is how to create a safe and comfortable pedestrian environment, which calls for more and more study and evaluation of outdoor wind environment. Wind tunnel experiment, as well as Computational Fluid Dynamics (CFD), is a primary method to study this issue. For wind tunnel experiment, the airflow and boundary conditions are more controllable and leading to reliable data. On commonly used wind tunnel platforms, researchers apply wedges and rough elements to create gradient wind of atmospheric boundary layer, which leaves the disadvantages of large size, not to mention high cost of construction and operation.
In this paper, the authors designed a simplified wind tunnel platform based on the theoretical model of atmospheric boundary layer. Two different methods of grids and thick plates with unequal spacing are adopted and tested. Upon comparison with theoretical formula, it turns out that gradient wind can be formed by both methods, while the thick plate method is superior with better performance. Furthermore, more experiments of thick plate method indicate that the larger the air supply volumes and the wider the thick plates, the better the gradient wind can be achieved.
This new wind tunnel platform can attain gradient wind of different landforms. It is more flexible and convenient than the traditional ones, with smaller land occupation, easier construction and operation, as well as lower cost. Therefore, we suggest more application of this new platform in the future experimental studies of outdoor wind environment for pedestrian comfort.
Experimental Study on the Human Exposure Level to Resuspended Particles in an Operating Room with Mixing Ventilation
1Norwegian University of Science and Technology, Norway; 2Norconsult AS, Norway
Resuspended particulate matter may carry germs that may cause surgical site infections of surgical patients. Meanwhile microorganisms carrying particles may pose a health threat to surgical staff. The aim of this study is to investigate the exposure level of both patients and health care workers to resuspended particles during the COV-19 pandemic. The measurements are conducted in a full-scale operating room laboratory in Norwegian University of Science and Technology. To simulate resuspended particles, tracer gas N2O was used to simulate the spread of resuspended particles. Positive pressure of 20 Pa, 10 Pa and negative pressure of -5 Pa were used between the OR and ambient room. Two scenarios were investigated: with and without an obstacle between the main surgeon and surgical table, respectively. Measurements of pollutant concentration were performed at six points including wound area of the patient, breathing zone of health care workers and upper surface of the instrument table is measured. The results show that the exposure level of wound area of the patient was highest in all cases, while the difference of exposure level reduces with the change of pressure difference from 20 Pa to - 5 Pa. Placing an obstacle between the main surgeon and operating table can effectively reduce not only the exposure level of the wound area of the patient. Due to the outdoor air flow penetrates into OR and affects the air distribution under negative pressure, the exposure level at -5 Pa is lower than that under 10 Pa and 20 Pa.
Infection Control Improvement of a Negative-Pressurized Pediatric Intensive Care Unit
1Department of Refrigeration, Air Conditioning and Energy Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan; 2Graduate Institute of Precision Manufacturing, National Chin-Yi University of Technology, Taichung 411, Taiwan; 3Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
The COVID-19 pandemic caused by the novel SARS-CoV-2 virus raises alarming concern around the healthcare facilities due to the significant increase in patient inflow. To isolate the patients from active community contact, negative-pressurized isolation rooms have been utilized in various health care facilities. Several studies have highlighted isolation rooms' improvement to accommodate more than one adult patient towards patient management. However, limited knowledge is available regarding the isolation room facilities for pediatric intensive care units (PICU) to accommodate more than one pediatric patient. In this aspect, this study investigates a negative-pressurized isolation room facility in PICU with minimal design modifications with the possibility that it can accommodate more than one pediatric patient. The field measurement was conducted to ensure the design compliance of Taiwan CDC. Computational fluid dynamics (CFD) was further utilized to numerically evaluate the HVAC system's role and the ventilation performance towards infection control. A simple protected air-jet curtain system with a new ventilation layout was proposed through this study to enhance the protection for both pediatric patients and medical staff. The results revealed that this proposed configuration could accommodate two patients with a significant contamination control through the expenditure of the least energy budget.
Air Quality and Heat-Related Health Impacts during Heat Events
1Department of Architectural Science, Ryerson University, Canada; 2School of Environment, Enterprise and Development, University of Waterloo, Canada
The combination of climate change, Urban Heat Island, and heatwave events is leading to higher daytime temperatures and causes elevated heat stress for urban dwellers. This magnified heat stress increases heat-related morbidity and mortality levels, mostly in vulnerable sectors of society, especially when correlated with poor air quality levels. This paper investigates the impact of high-to-extreme heat events and poor air quality on community health responses (mortalities and emergency department visits). It searches for correlations among meteorological parameters (air temperature and relative humidity), air quality (ground-level ozone and particulate matters concentrations), and the health response measured by the daily records of emergency visits and mortalities. A novel multi-dimensional clustering approach was proposed by combining hierarchical and k-means clustering to promote flexibility and robustness to improve the correlation procedure. The study focused on the health records of the elderly population with respiratory-cardiovascular diseases. The developed method was tested by investigating the instant impact of ambient air temperature, relative humidity, ground-level ozone, and fine particulate matter on the health records during hot and warm seasons in municipalities of Mississauga and Brampton, Peel Region, ON, CA for 15 years. The analysis confirmed the association between extreme heat conditions and poor air quality levels and mortalities and emergency visits of elderly people with respiratory-cardiovascular diseases.