scholarly journals Diurnal and seasonal variation in air exchange rates and interzonal airflows measured by active and passive tracer gas in homes

2016 ◽  
Vol 104 ◽  
pp. 178-187 ◽  
Author(s):  
Gabriel Bekö ◽  
Sine Gustavsen ◽  
Marie Frederiksen ◽  
Niels Christian Bergsøe ◽  
Barbara Kolarik ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Exchange Rates ◽  
Passive Tracer ◽  
Tracer Gas ◽  
Air Exchange

Winter Measurements of Air Exchange Rates Using Tracer Gas Technique and Quantification of Gaseous Emissions from a Naturally Ventilated Dairy Barn

2011 ◽  
Vol 27 (6) ◽  
pp. 1015-1025 ◽  
Author(s):  
M. Samer ◽  
M. Fiedler ◽  
H.-J. Müller ◽  
M. Gläser ◽  
C. Ammon ◽  
...  
Keyword(s):  
Exchange Rates ◽  
Gaseous Emissions ◽  
Tracer Gas ◽  
Air Exchange

scholarly journals Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature, Relative Humidity, and Air Exchange Rate

2012 ◽  
Vol 78 (23) ◽  
pp. 8289-8297 ◽  
Author(s):  
Mika Frankel ◽  
Gabriel Bekö ◽  
Michael Timm ◽  
Sine Gustavsen ◽  
Erik Wind Hansen ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Relative Humidity ◽  
Exchange Rates ◽  
Seasonal Variations ◽  
Air Exchange Rate ◽  
Four Seasons ◽  
Significant Seasonal Variation ◽  
Indoor Fungi ◽  
Inhalable Dust ◽  
Air Exchange

ABSTRACTIndoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors,n= 127; outdoors,n= 37). Measurements included culturable fungi and bacteria, endotoxin,N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m3) and were lowest in winter (median, 26 CFU/m3). Indoor bacteria peaked in spring (median, 2,165 CFU/m3) and were lowest in summer (median, 240 CFU/m3). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi andN-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.

The impact of mechanical ventilation operation strategies on indoor CO2 concentration and air exchange rates in residential buildings

2020 ◽  
pp. 1420326X2096076
Author(s):  
Pedro F. Pereira ◽  
Nuno M. M. Ramos
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Exchange Rates ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Ventilation Strategy ◽  
The Impact ◽  
Mechanical Extraction ◽  
Air Exchange

In Portugal, residential buildings commonly have their ventilation strategy changed after commissioning. This occurs due to the building managers' willingness to reduce shared costs with the electricity needed for fan operation. However, this option is not technically supported, and the effects of such a strategy on indoor air quality-related to human pollutants are yet to be quantified. CO2 was monitored in 15 bedrooms and air exchange rates were calculated for each room. The air exchange rate values ranged from 0.18 to 0.53 h−1 when mechanical extraction ventilation was off, and from 0.45 to 0.90 h−1 when mechanical extraction ventilation was on, which represents an average increase of 119%. With the current intermittent ventilation strategy, all rooms remain above 1500 ppm for a given percentage of time, and 12 rooms presenting CO2 concentrations above 2000 ppm. Simulations of theoretical CO2 concentrations, for a non-interrupted mechanical ventilation strategy show that no rooms would accumulate CO2 concentrations above 2000 ppm, and only 25% would present CO2 concentrations above 1500 ppm. Pearson correlations between the monitored CO2 and human and spatial factors identified two relevant parameters. Those parameters correspond to ratios between CO2 generation and floor area ([Formula: see text]), and airflow with CO2 generation ([Formula: see text]). The proposed ratios could be used as ways to optimise ventilation costs and indoor air quality.

Estimating residential air exchange rates in rural Bangladesh using a near field-far field model

2021 ◽  
pp. 108325
Author(s):  
Darpan Das ◽  
Emma Moynihan ◽  
Mark Nicas ◽  
Eric D. McCollum ◽  
Salahuddin Ahmed ◽  
...  
Keyword(s):  
Exchange Rates ◽  
Field Model ◽  
Near Field ◽  
Far Field ◽  
Rural Bangladesh ◽  
Air Exchange

scholarly journals Estimation of bias with the single‐zone assumption in measurement of residential air exchange using the perfluorocarbon tracer gas method

Indoor Air ◽  
2014 ◽  
Vol 25 (6) ◽  
pp. 610-619 ◽  
Author(s):  
K. Van Ryswyk ◽  
L. Wallace ◽  
D. Fugler ◽  
M. MacNeill ◽  
M. È. Héroux ◽  
...  
Keyword(s):  
Tracer Gas ◽  
Air Exchange

scholarly journals A trace gas technique for measuring clothing microclimate air exchange rates

1972 ◽  
Vol 29 (4) ◽  
pp. 378-386 ◽  
Author(s):  
G. W. Crockford ◽  
M. Crowder ◽  
S. P. Prestidge
Keyword(s):  
Exchange Rates ◽  
Trace Gas ◽  
Air Exchange
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