scholarly journals Room HVAC Influences on the Removal of Airborne Particulate Matter: Implications for School Reopening during the COVID-19 Pandemic

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7463
Author(s):  
Ali Mohammadi Nafchi ◽  
Vincent Blouin ◽  
Nigel Kaye ◽  
Andrew Metcalf ◽  
Katie Van Valkinburgh ◽  
...  
Keyword(s):  
Higher Education ◽  
Indoor Air ◽  
Complex Function ◽  
Airborne Particulate Matter ◽  
Ventilation Rate ◽  
Air Distribution ◽  
Internal Source ◽  
Hvac System ◽  
Airborne Particulate ◽  
And Performance

(1) Background: Many schools and higher education settings have confronted the issue of reopening their facilities after the COVID-19 pandemic. In response, several airflow strategies spanning from adding portable air purifiers to major mechanical overhauls have been suggested to equip classrooms with what is necessary to provide a safe and reliable environment. Yet, there are many unknowns about specific contributions of the building system and its design and performance on indoor air quality (IAQ) improvements. (2) Methods: this study examined the combined effect of ventilation type, airflow rates, and filtration on IAQ in five different classrooms. Experiments were conducted by releasing inert surrogate particles into the classrooms and measuring the concentrations in various locations of the room. (3) Results: we showed that while the distribution of particles in the space is a complex function of space geometry and air distribution configurations, the average decay rate of contaminants is proportional to the number of air changes per hour in the room. (4) Conclusions: rooms with a central HVAC system responded quicker to an internal source of contamination than rooms with only fan coil units. Furthermore, increasing the ventilation rate without improved filtration is an inefficient use of energy.

The Analysis of the Impact of the Louver on the Natural Ventilation

2011 ◽  
Vol 243-249 ◽  
pp. 6997-7000
Author(s):  
Yi Wang ◽  
Pan Lu ◽  
Hai Bing Yao ◽  
Jia Ping Liu ◽  
Lu Lu Chen
Keyword(s):  
Velocity Profile ◽  
Pressure Distribution ◽  
Wind Velocity ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Model Building ◽  
Ventilation Rate ◽  
Air Distribution ◽  
Discharge Coefficients ◽  
The Impact

The louver affects natural ventilation rate and indoor air distribution. In this paper, the wind velocity profile and pressure distribution in the natural ventilation model building were simulated through CFD. And how different rotation angles of the shutter and different incidence angles of the wind affect natural ventilation rate were studied. Then, the influences of shutters on the discharge coefficients were analyzed, and use principles of the louver equipped in the building were proposed.

scholarly journals Characterization of Indoor Air Quality on a College Campus: A Pilot Study

2019 ◽  
Vol 16 (15) ◽  
pp. 2721 ◽  
Author(s):  
Grant Erlandson ◽  
Sheryl Magzamen ◽  
Ellison Carter ◽  
Julia L. Sharp ◽  
Stephen J. Reynolds ◽  
...  
Keyword(s):  
Higher Education ◽  
Carbon Dioxide ◽  
Particulate Matter ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
College Campuses ◽  
College Campus ◽  
And Performance

Recent construction trends on college campuses have demonstrated a shift to designing buildings with features focused on sustainability. However, few studies have investigated indoor air quality in institutions of higher education, particularly in sustainably designed buildings. The objective of this study was to evaluate the association of building and occupancy on indoor air quality within and between higher education buildings. We measured particulate matter, formaldehyde, carbon dioxide, and nitrogen oxides in LEED certified, retrofitted, and conventional building types on a college campus. Three size fractions of particulate matter were measured in each building. We conducted multi-zonal, 48-h measurements when the buildings were occupied and unoccupied. Outdoor particulate matter was significantly higher (PM2.5 = 4.76, PM4 = 17.1, and PM100 = 21.6 µg/m3) than in classrooms (PM2.5 = 1.7, PM4 = 4.2, and PM100 = 6.7 µg/m3) and common areas (PM2.5 = 1.3, PM4 = 4.2, and PM100 = 4.8 µg/m3; all p < 0.001). Additionally, concentrations of carbon dioxide and particulate matter were significantly higher (p < 0.05) during occupied sampling. The results suggest that occupancy status and building zone are major predictors of indoor air quality in campus buildings, which can, in turn, increase the concentration of contaminants, potentially impacting occupant health and performance. More research is warranted to reveal building features and human behaviors contributing to indoor exposures.

scholarly journals Analysis on the Exhaust Air Recirculation of the Ventilation System in Multi-Story Building

2021 ◽  
Vol 11 (10) ◽  
pp. 4441
Author(s):  
Seonghyun Park ◽  
Hyungyu Park ◽  
Janghoo Seo
Keyword(s):  
Mechanical Ventilation ◽  
South Korea ◽  
Indoor Air ◽  
Ventilation System ◽  
Ventilation Rate ◽  
Cfd Analysis ◽  
Recirculation Rate ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance ◽  
Story Building

In South Korea, the installation of a mechanical ventilation system is mandatory for the management of indoor air quality, and various studies concerning the ventilation rate and performance of the ventilation system have been conducted. However, only a few studies have been conducted regarding the recirculation rate of the ventilation system. If the appropriate arrangement of intake and exhaust vents in the ventilation system is not considered, the pollutants emitted from the circulation movement may be recirculated into the indoor environment and cause the degradation of the performance of the ventilation system. Therefore, this study aimed to quantitatively analyze the recirculation rate of pollutants emitted from a kindergarten building with an installed mechanical ventilation system in Seoul, South Korea, using computational fluid dynamics (CFD) analysis, and analyze the effectiveness of the guide panel installed for the prevention of the pollutants’ recirculation. The number of cases for the CFD analysis was set to a total of ten based on the ventilation rate in a mechanical ventilation system, external wind direction, and the existence of the guide panel for preventing the recirculation of exhaust air. The maximum recirculation rate of exhaust air without the installation of a guide panel was shown to be 20.0%. The maximum recirculation rate in the case where the external wind speed, direction of wind, and the ventilation rate were assumed to be identical to the other case but the guide panel for preventing the recirculation of exhaust air was assumed to be installed was 7.7%, 12.3% lower compared with the case with maximum recirculation rate.

scholarly journals The Impact of Bushfire Smoke on Cattle—A Review

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 848
Author(s):  
Benjamin Eid ◽  
David Beggs ◽  
Peter Mansell
Keyword(s):  
Particulate Matter ◽  
Prolonged Exposure ◽  
Negative Impact ◽  
Airborne Particulate Matter ◽  
Mortality Rates ◽  
Airborne Particulate ◽  
Primary Mechanism ◽  
Background Mortality ◽  
Fire Front ◽  
The Impact

In 2019–2020, a particularly bad bushfire season in Australia resulted in cattle being exposed to prolonged periods of smoke haze and reduced air quality. Bushfire smoke contains many harmful pollutants, and impacts on regions far from the fire front, with smoke haze persisting for weeks. Particulate matter (PM) is one of the major components of bushfire smoke known to have a negative impact on human health. However, little has been reported about the potential effects that bushfire smoke has on cattle exposed to smoke haze for extended periods. We explored the current literature to investigate evidence for likely effects on cattle from prolonged exposure to smoke generated from bushfires in Australia. We conducted a search for papers related to the impacts of smoke on cattle. Initial searching returned no relevant articles through either CAB Direct or PubMed databases, whilst Google Scholar provided a small number of results. The search was then expanded to look at two sub-questions: the type of pollution that is found in bushfire smoke, and the reported effects of both humans and cattle being exposed to these types of pollutants. The primary mechanism for damage due to bushfire smoke is due to small airborne particulate matter (PM). Although evidence demonstrates that PM from bushfire smoke has a measurable impact on both human mortality and cardiorespiratory morbidities, there is little evidence regarding the impact of chronic bushfire smoke exposure in cattle. We hypothesize that cattle are not severely affected by chronic exposure to smoke haze, as evidenced by the lack of reports. This may be because cattle do not tend to suffer from the co-morbidities that, in the human population, seem to be made worse by smoke and pollution. Further, small changes to background mortality rates or transient morbidity may also go unreported.

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