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Residents tend to close the doors and windows of their residential kitchens in severe cold conditions, making insufficient outdoor air supply and aggravating indoor air pollution. In order to understand the ventilation and pollution status of the residential kitchens in a severe cold region and improve the ventilation system, this study used questionnaires, on-site tests, and Computational Fluid Dynamics (CFD) simulation to analyze a pollution and ventilation case in Shenyang, China. The method of using ceiling openings to compensate for outdoor air supply was proposed and optimized to improve air distribution in the residential kitchen. The average CO2 concentration in the breathing region, air velocity, and temperature levels in the kitchen, before and after the improvement, were compared. The results indicated that the kitchen pollution in severe cold area of Shenyang is serious, and the ventilation habit has regional characteristics. Furthermore, the overall kitchen environment including air velocity, temperature, pollutant levels, static pressure, CO2 concentration, indoor airflow fluctuation, and cooking fire were obviously improved for the ceiling make-up air cases. These findings provide a basis for improving the reasonable air distribution of residential kitchens in cold regions and for building a thermally comfortable environment.

This paper describes the development of a new adaptation of the traditional tracer gas test (TGT) used for total air change rates (ACH) measurement. This adapted TGT, based on constant tracer injec...

Children under 15 years spend over six hours per day in school buildings and are particularly vulnerable to the effects of poor indoor air quality (IAQ). However long-term monitoring of indoor environmental conditions is limited in Australian schools. This study evaluates IAQ in ten Australian school classrooms in the temperate settings of Victoria. Temperature, relative humidity, CO2 concentration, PM2.5 and PM10 were monitored over a period of one year. The temperature and relative humidity values in the monitored classrooms ranged between 18.7��C and 23.8��C and 44���63 RH%, respectively, indicating that the conditions have been mechanically controlled. The average air change (ACH) rates in the 10 school classrooms varied considerably (range: 0.7���4.83 ACH). The ventilation rates ranged from 1.6 Ls���1 to 11.5 Ls���1 per person with 7 out of the 10 classrooms showing ventilation rates below the recommended minimum. This study points to the need for increasing ventilation rates in classrooms.

All-fresh-air heating, ventilation, and air conditioning systems with high air exchange rates are typically applied in conventional laboratory animal houses (LAHs), resulting in high energy consump...

Contemporary spaces for surgery are highly energy intensive, much of which is attributed to powerful air conditioning systems intended to force air down onto the patient, surgical staff and instrum...

Severing of the pilot balloon of an endotracheal tube (ETT) results in cuff deflation and may lead to complications including inadequate patient ventilation, increased risk of aspiration and infection, and operating room air pollution with anesthetic gases. In situations where ETT exchange or reintubation may pose a significant risk to the patient, temporary repair of the severed cuff tubing can be helpful until it is safe to address the problem with replacing the ETT. Simple and effective repair methods can be achieved using readily available materials in the operating room, including intravenous cannulas, hypodermic syringes, and epidural clamp connectors. However, choosing which technique or method depends mainly on personal preference, equipment availability, and provider comfort and experience. We present a 12-year-old adolescent who presented for anesthetic care for extensive burn injury. During removal of the dressing around the head and face, the tubing of the pilot balloon of the ETT was inadvertently cut. Options for dealing with such problems are discussed, including techniques to allow for temporary repair and re-inflation of the deflated cuff.

The energy consumed by the heating, ventilation, and air conditioning (HVAC) system accounts for a large part of the energy consumption of buildings. Solar energy technologies in buildings have att...

The intelligentization of mine ventilation is the inevitable development trend of ventilation system. Rapid, precise, and on-demand (RPOD) adjustment of air volume is one of the main problems that ...

Green buildings and sustainable designs require architectural designers to go beyond the basic building codes to improve overall building energy performance, optimize building ventilation, minimize...

In this paper, heating and ventilation air conditioning system (HVAC) dataset for a medium-large size building in Romania has been used. It has been collected in one year. Linear state-space model ...

Based on a case study of the undersea metro interval tunnel, this study proposes a model to evaluate the Ventilation and Smoke Exhaust System (VSES). In the VSES experiments, data of fan frequencie...

High-flow nasal cannula is a non-invasive ventilation system that was introduced as an alternative to continuous positive airway pressure), with a marked increase in its use in pediatric care settings. However, the expected budget impact of this intervention has not been explicitly estimated. This study aimed to evaluate the budget impact of the high-flow nasal cannula for acute bronchiolitis in Colombia.A budget impact analysis was performed to evaluate the potential financial impact deriving from high-flow nasal cannula during 2020. The analysis considered a 5-year time horizon and Colombian National Health System perspective. The incremental budget impact was calculated by subtracting the cost of the new treatment, in which a high-flow nasal cannula is reimbursed, from the cost of the conventional treatment without a high-flow nasal cannula (supplemental oxygen through a nasal cannula up to a maximum of 2 liters per minute). Univariate one-way sensitivity analyses were performed.In the base-case analysis the 5-year costs associated with high-flow nasal cannula and no- high-flow nasal cannula were estimated to be US$159,585,618 and US$172,751,689 respectively, indicating savings for Colombian National Health equal to US$13,166,071 if the high-flow nasal cannula is adopted for the routine management of patients with acute bronchiolitis. This result was robust in univariate sensitivity one-way analysis.High-flow nasal cannula was cost-saving in emergency settings for treating infants with acute bronchiolitis. This evidence can be used by decision-makers in our country to improve clinical practice guidelines and should be replicated to validate their results in other middle-income countries.

A numerical study of three-dimensional turbulent mixed convection in a ventilated, thermally insulated cavity containing a hot body (cylindrical or cubical) is conducted. The cavity has an inlet an...

While occupancy-based control and other demand management control strategies have demonstrated potential, little is known about how these changes in heating, ventilation, and air-conditioning (HVAC...

In this paper, we propose a new intelligent temperature-controlled ventilated double-layer Trombe wall system for cold climate zones. This system consists of an insulation layer, an inner air chann...

In view of the ageing domestic building stock and increasing reliance on fossil fuels for cooling and ventilation of buildings, there is an urgent need for improved design knowledge and sustainable...

Introduction: Motor neurone disease (MND) is characterized by rapidly progressive motor neurone degeneration which leads to muscle wasting. Mortality and morbidity are due to respiratory muscle failure which may be offset by ventilation. The aim of this observational study was to quantify the number and characteristics of patients living with MND choosing tracheostomy ventilation (TV) in the UK. Methods: Long-term ventilation services in the UK were invited to undertake a retrospective 5-year audit of MND patients under their care between April 2013 and March 2018 who had TV. Patient characteristics, the time spent on ventilation, hospital length of stay, discharge destination, and survival data were collected. Results: Sixty-eight MND patients were initiated on TV over the 5-year period. Eighty-one percent of patients received TV in an emergency setting with more than a third of these undiagnosed at presentation. Patients choosing elective TV were more likely to be male (85%) have a bulbar presentation (54%) and an increased survival of 10 months over the observation period. The mean length of hospital stay post TV was 136 days. Two-thirds of patients were discharged to their own home. Conclusion: Very few patients living with MND in the UK are currently receiving TV. In those who choose TV, there may be a survival advantage to planning an elective procedure. Despite the long inpatient stay and high care costs involved a majority of patients survived and were discharged to their own home.

This article discusses the design of unidirectional airflow systems used to ventilate operating theatres and provide low concentrations of airborne micro-organisms during surgical operations. Also described are tests that can be used to confirm that unidirectional airflow systems are well designed and perform correctly when installed and during their lifetime. Reasons are given for the failure of unidirectional airflow systems to provide low concentrations of airborne micro-organisms and reduce joint infection rates after total joint arthroplasty when compared to conventional mixed-airflow operating theatres.

Computational fluid dynamics (CFD) modelling was performed to simulate spatial and temporal airborne pathogen concentrations during an observed COVID-19 outbreak in a restaurant in Guangzhou, China...

The amount of energy needed for HVAC (Heating, Ventilation and Air Conditioning) systems in the building depends on a variety of factors, and one of the most important is the conduction load throug...

A traditional residence is not only a symbol of historic wisdom, but also represents the development of superior building experience. The weather in regions south of the Yangtze River is wet and ho...

Indoor concentrations of PM10, PM2.5, CO, and CO2 were measured in 25 naturally ventilated urban residences during the winter and summer seasons in Alexandria, Egypt. Ambient air samples were also collected simultaneously for comparison to indoor measurements. Furthermore, data for air exchange rates, home characteristics, and indoor activities during sampling were collected. It was found that the average indoor PM10, PM2.5, CO, and CO2 concentrations for all homes in winter were 119.4 ± 30.9 μg/m3, 85.2 ± 25.8 μg/m3, 1.6 ± 0.8 ppm, and 692.4 ± 144.6 ppm, respectively. During summer, the average indoor levels were 98.8 ± 21.8 μg/m3, 67.8 ± 14.9 μg/m3, 0.5 ± 0.5 ppm, and 558.2 ± 66.2 ppm, respectively. The results indicate that the indoor daily averages of PM10 and PM2.5 concentrations were higher than the World Health Organization (WHO) guidelines for all selected homes in the two sampling periods. For CO and CO2 levels, the indoor daily averages for all monitored homes were less than the WHO guideline and the American National Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ANSI/ASHRAE) Standard 62.1, respectively. A strong seasonal variability was observed, with air quality being particularly poor in winter. Due to increased ventilation rates in summer, indoor levels of air pollutants were strongly dependent on ambient levels, while in winter the indoor concentrations were more strongly affected by indoor sources due to increased human activities and poor ventilation. In addition, stronger indoor/outdoor correlation of air pollutants' levels was found in summer than in winter probably due to higher ventilation and infiltration in the summer. The study also attempted to understand the potential sources and the various determinants that influence indoor PM, CO, and CO2 concentrations in the two seasons. The findings can assist policymakers to better understand the indoor air pollution problem and to provide a sound basis for the development of proper national IAQ standards in Egypt.Implications: Personal exposure is considerably influenced by indoor air pollution which increases health risks. Assessment of indoor air quality has become a more significant issue in Egypt as people tend to spend most of their time inside buildings, especially in their homes. Currently, there is a lack of research on residential indoor air quality in Egyptian cities in terms of the spatial and temporal variation which prevents an accurate assessment of the current situation to develop effective mitigation measures and to establish national indoor air quality standards. This article is considered the first research studying the effect of seasonality on indoor concentrations of PM10, PM2.5, CO, and CO2 in urban residences in Alexandria. It also studies the indoor/outdoor relationship of air pollutants' levels and identifies their major sources as well as the various determinants that influence their indoor concentrations.

In this study, a heat recovery exchanger was designed to provide indoor air quality (IAQ) and energy efficiency for intercity buses used in public transport. The heat recovery exchanger enabled the...

Ceiling diffusers are one of the most important elements of ventilation and air-conditioning installations. They have a significant impact on the speed and temperature distribution of air. The basi...

Chillers play essential roles in the heating, ventilation and air conditioning (HVAC) systems to ensure the required thermal comfort. To reduce the operational risk such as faulty operation or ener...

The impinging jet ventilation (IJV) system has been proposed as a new air distribution strategy and is expected to overcome the disadvantages of mixing ventilation (MV) system, which is the most wi...

Demand-controlled ventilation (DCV) is a crucial part of ventilation design used in buildings and its effects are widely studied in modern construction. To assess the effect of DCV, accurate models...

In this paper, we will focus on the retrofit of the ventilation system setup on the premise of reserving the original VAV system. Therefore, a combination of the existing VAV system and the dedicat...

The present study examines the development of a push-pull ventilation system with localized extraction located for use in wastewater treatment. The proposed approach aims to minimize the concentrat...

Bedroom ventilation is crucial for providing good indoor air quality, which may contribute to achieving undisturbed sleep. This study presents a detailed characterization of bedroom carbon dioxide ...

As homeotherms, human beings rely on garments to maintain thermal equilibrium and comfort. When clothing cannot meet their thermal comfort requirements, they have to use the heating, ventilation, a...

Background: As the global outbreak of COVID-19 continues to ravage the world, it is important to understand how frontline clinicians manage ventilatory support and the various limiting factors. / Methods: An online survey composed of 32 questions was developed and validated by an international expert panel. / Results: Overall, 502 respondents from 40 countries across six continents completed the survey. The mean number (±SD) of ICU beds was 64 ± 84. The most popular initial diagnostic tools used for treatment initiation were arterial blood gas (48%) and clinical presentation (37.5%), while the national COVID-19 guidelines were the most used (61.2%). High flow nasal cannula (HFNC) (53.8%), non-invasive ventilation (NIV) (47%), and invasive mechanical ventilation (IMV) (92%) were mostly used for mild, moderate, and severe COVID-19 cases, respectively. However, only 38.8%, 56.6% and 82.9% of the respondents had standard protocols for HFNC, NIV, and IMV, respectively. The most frequently used modes of IMV and NIV were volume control (VC) (36.1%) and continuous positive airway pressure/pressure support (CPAP/PS) (40.6%). About 54% of the respondents did not adhere to the recommended, regular ventilator check interval. The majority of the respondents (85.7%) used proning with IMV, with 48.4% using it for 12– 16 hours, and 46.2% had tried awake proning in combination with HFNC or NIV. Increased staff workload (45.02%), lack of trained staff (44.22%) and shortage of personal protective equipment (PPE) (42.63%) were the main barriers to COVID-19 management. / Conclusion: Our results show that general clinical practices involving ventilatory support were highly heterogeneous, with limited use of standard protocols and most frontline clinicians depending on isolated and varied management guidelines. We found increased staff workload, lack of trained staff and shortage of PPE to be the main limiting factors affecting global COVID-19 ventilatory support management.

The present study investigated indoor and outdoor concentrations of two particulate matter size fractions (PM10 and PM2.5) and CO2 in 20 urban homes ventilated naturally and located in one congested residential and commercial area in the city of Alexandria, Egypt. The results indicate that the daily mean PM2.5 concentrations measured in the ambient air, living rooms, and kitchens of all sampling sites exceeded the WHO guideline by 100%, 65%, and 95%, respectively. The daily mean outdoor and indoor PM10 levels in all sampling sites were found to exceed the WHO guideline by 100% and 80%, respectively. The indoor PM10 and PM2.5 concentrations were significantly correlated with their corresponding outdoor levels, as natural ventilation through opening doors and windows allowed direct transfer of outdoor airborne particles into the indoor air. Most of the kitchens investigated had higher indoor concentrations of PM2.5 and CO2 than in living rooms. The elevated levels of PM2.5 and CO2 in domestic kitchens were probably related to inadequate ventilation. The current study attempted to understand the sources and the various indoor and outdoor factors that affect indoor PM10, PM2.5 and CO2 concentrations. Several domestic activities, such as smoking, cooking, and cleaning, were found to constitute important sources of indoor air pollution. The indoor pollution caused by PM2.5 was also found to be more serious in the domestic kitchens than in the living rooms and the results suggest that exposure to PM2.5 is high and highlights the need for more effective control measures. Implications: Indoor air pollution is a complex problem that involves many determinant factors. Understanding the relationships and the influence of various indoor and outdoor factors on indoor air quality is very important to prioritize control measures and mitigation action plans. There is currently a lack of research studies in Egypt to investigate determinant factors controlling indoor air quality for urban homes. The present study characterizes the indoor and outdoor concentrations of PM10, PM2.5, and CO2 in residential buildings in Alexandria city. The study also determines the indoor and outdoor factors which influence the indoor PM and CO2 concentrations as well as it evaluates the potential indoor sources in the selected homes. This research will help in the development of future indoor air quality standards for Egypt.

It is widely acknowledged that buildings that are well designed, constructed and operated can generate health, well-being and prosperity benefits. Inadequate ventilation, poor indoor air quality, c...

Underground mines have the risk of accumulating gases if not ventilated properly or during and after emergency situations when ventilation controls become damaged or stop working. Common gases that...

Owing to design and operation limitations, most multi-zone variable air volume (VAV) systems in existing buildings still follow traditional techniques for ventilation. In recent ventilation researc...

In this study, effect of air change rate (air change per hour – ACH) on indoor particle dispersion and deposition in a ventilated room is investigated. A reduced-scale model is designed to conduct ...

Bioaerosols are known to be an important transmission pathway for SARS-CoV-2. We report a framework for estimating the risk of transmitting SARS-CoV-2 via aerosols in laboratory and office settings, based on an exponential dose-response model and analysis of air flow and purification in typical heating, ventilation, and air conditioning (HVAC) systems. High-circulation HVAC systems with high-efficiency particulate air (HEPA) filtration dramatically reduce exposure to the virus in indoor settings, and surgical masks or N95 respirators further reduce exposure. As an example of our risk assessment model, we consider the precautions needed for a typical experimental physical science group to maintain a low risk of transmission over six months of operation. We recommend that, for environments where fewer than five individuals significantly overlap, work spaces should remain vacant for between one (high-circulation HVAC with HEPA filtration) to six (low-circulation HVAC with no filtration) air exchange times before a new worker enters in order to maintain no more than 1% chance of infection over six months of operation in the workplace. Our model is readily applied to similar settings that are not explicitly given here. We also provide a framework for evaluating infection mitigation through ventilation in multiple occupancy spaces.

The environmental design of residential buildings is an arduous process involving a large number of parameters and objectives . Additionally, with the development trend of high-performance housing ...

Operating room ventilation is quite important to protect patients from infection risk inside a surgical field. The laminar flow units (LAF) used in these applications contribute to removal of patho...

Even in case ventilation system is operating in optimal fashion, indoor air quality could be varied depending on the indoor contaminant release occasions. Thus, accurate and rapid identification of...

A novel DCV-system controls the air-change rate for each apartment in multifamily buildings based on two indoor air parameters: 1) the moisture load (supply), and 2) volatile organic compounds. Wit...

This study investigated the energy conservation of a non-insulated old apartment with a ventilated sunspace in Qingdao, China. The ventilation between the bedroom and sunspace of the apartment was ...

To improve the ventilation and air-conditioning energy efficiency of buildings in hot and dry climates, this paper proposed and experimentally investigated an indirect flash evaporative cooling (IF...

Heating, ventilation and air conditioning (HVAC) systems play an essential role in demand response (DR) programs. In this paper, a fuzzy controller is designed to adjust the HVAC set-points optimal...

Public attention has been drawn to the commercial restaurant cooking emission since it can cause health and hygiene risks, reduction of the efficiency of the ventilation system, and even fire accid...

Various industrial applications such as medical/pharmaceutical sprays, heating, ventilation and air conditioning systems, and other solid/liquid atomization processes benefit from the characterizat...

Building ventilation systems are responsible for providing a favorable thermal condition, as well as maintaining acceptable indoor air quality. Thus, ventilation rates are extremely high in hospita...