Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows

Wallace, Lance; Emmerich, Steven J.; Howard-Reed, Cynthia

doi:10.1038/sj.jea.7500229

Cited by 228 publications

(156 citation statements)

References 15 publications

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“…Table 4.4 shows that while there is a significant relationship between the air change rates and the indoor-outdoor relative humidity difference, the same cannot be said about the indooroutdoor air temperature difference. This is at variance with the observations of Wallace et al [36] as well as Howard-Reed et al [37], who concluded that indoor-outdoor temperature difference had a clear effect on air change rates. Wallace et al [36] found that extreme temperature difference of 30°C resulted in an increase of about 0.5-0.6 air changes per hour.…”

Section: Airflow Rates In the Selected Spacescontrasting

confidence: 57%

Assessment of users' responses to air change rates in free running office buildings

et al. 2017

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Abstract. Often, building assessments do not account for users' social concerns in relation to buildings' physical characteristics. This study, therefore, assessed the responses of free running office building users to the objective measurements of air change rates in the spaces they occupy. This was done with a view to define a suitable quantitative expression for the social concerns of the users in building assessments, as well as with a view to examine the relationships between the users' responses and the physical characteristics of free running buildings. Measurements were taken in eight low-rise office buildings regarding indoor/outdoor air parameters to capture the air change rates in the buildings. These were done in 50 different spaces within the buildings at different floor levels and different fenestration orientations. The air change rates were correlated along social and physical dimensions with the responses of the occupants captured through questionnaire. Some relationships were observed among the social characteristics of the users and their rating of air change rates in the spaces, but none were statistically significant. Linear regression analysis, however, shows that one of the buildings' physical characteristics has a strong relationship with the users' responses to air change rates.

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Section: Airflow Rates In the Selected Spacescontrasting

confidence: 57%

Assessment of users' responses to air change rates in free running office buildings

et al. 2017

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“…36 In a study carried out in Greater Boston, Massachusetts -a region with a similar climate to the Greater Toronto Area -there was a strong correlation between average indoor and outdoor air temperature when outdoor temperatures rose above 13°C. 37 As outdoor temperature fell below 13°C, the average indoor temperature remained steady at 18°C.…”

Section: Limitationsmentioning

confidence: 99%

Influence of environmental temperature on risk of gestational diabetes

Booth

Luo

Park

et al. 2017

CMAJ

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The impact of climate variability on health has become increasingly relevant given the global rise in air temperatures over the past century.1,2 Extreme weather patterns can adversely influence health -directly, as in the case of hyperor hypothermia -and indirectly, by triggering respiratory exacerbations, infectious outbreaks, water-borne diseases and injuries. However, there is also growing evidence supporting a link between air temperature, metabolic function and energy expenditure. Brown adipose tissue aids with acclimatization to cold through its unique ability to generate heat by uncoupling cellular respiration from mitochondrial adenosine triphosphate (ATP) synthesis.4-6 Based on findings from studies involving animals and humans, the effects of brown adipose tissue activation extend beyond thermogenesis, by influencing whole-body metabolism and possibly overall body weight.7-18 Small intervention trials involving humans have suggested that even mild exposure to ambient cold -such as lowering a thermostat from 24°C to 19°C -can increase activity of brown adipose tissue by 30%-40%, resulting in substantial improvements in insulin sensitivity. [15][16][17][18] In theory, greater insulin sensitivity should improve glucose handling, but whole-population studies evaluating the potential for cold exposure to reduce glucose mishandling are lacking.We examined the impact of variation in outdoor air temperature on the risk of gestational diabetes mellitus, a transient form of diabetes arising by midpregnancy. Placental hormones lead to a temporary state of insulin resistance, starting in the second trimester of pregnancy and continuing until delivery.19 Gestational diabetes mellitus arises when the compensatory increase in insulin production fails to maintain normal blood glucose levels. This condition affects more than 15 million pregnancies worldwide each year 20 and can have serious consequences for mother, baby and the delivery process. [21][22][23] Hence, gestational diabetes mellitus offers an opportunity to study the short-term effect of ambient outdoor temperature on human metabolism. ABSTRACT BACKGROUND: Cold-induced thermogenesis is known to improve insulin sensitivity, which may become increasingly relevant in the face of global warming. The aim of this study was to examine the relation between outdoor air temperature and the risk of gestational diabetes mellitus.

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“…The authors conclude that window-opening behaviors must be determined for estimating occupant exposures to outdoor pollutants given that open doors and windows substantially affect home AER and indoor pollutant concentrations. Wallace et al (2002) present a year-long time-series of AER measurements made in the Reston, VA home discussed above. The AER, which averaged 0.65 h À1 for this home over the year, increased to 2 h À1 for extended periods and to 3 h À1 for short periods when external windows were opened.…”

Section: Air-exchange Ratementioning

confidence: 99%

A pilot study using scripted ventilation conditions to identify key factors affecting indoor pollutant concentration and air exchange rate in a residence

Johnson¹,

Myers

Kelly

et al. 2004

J Expo Sci Environ Epidemiol

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A pilot study was conducted using an occupied, single-family test house in Columbus, OH, to determine whether a script-based protocol could be used to obtain data useful in identifying the key factors affecting air-exchange rate (AER) and the relationship between indoor and outdoor concentrations of selected traffic-related air pollutants. The test script called for hourly changes to elements of the test house considered likely to influence air flow and AER, including the position (open or closed) of each window and door and the operation (on/off) of the furnace, air conditioner, and ceiling fans. The script was implemented over a 3-day period (January 30-February 1, 2002) during which technicians collected hourly-average data for AER, indoor, and outdoor air concentrations for six pollutants (benzene, formaldehyde (HCHO), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO), nitric oxide (NO), and nitrogen oxides (NO x )), and selected meteorological variables. Consistent with expectations, AER tended to increase with the number of open exterior windows and doors. The 39 AER values measured during the study when all exterior doors and windows were closed varied from 0.36 to 2.29 h À1 with a geometric mean (GM) of 0.77 h À1 and a geometric standard deviation (GSD) of 1.435. The 27 AER values measured when at least one exterior door or window was opened varied from 0.50 to 15.8 h À1 with a GM of 1.98 h À1 and a GSD of 1.902. AER was also affected by temperature and wind speed, most noticeably when exterior windows and doors were closed. Results of a series of stepwise linear regression analyses suggest that (1) outdoor pollutant concentration and (2) indoor pollutant concentration during the preceding hour were the ''variables of choice'' for predicting indoor pollutant concentration in the test house under the conditions of this study. Depending on the pollutant and ventilation conditions, one or more of the following variables produced a small, but significant increase in the explained variance (R 2 -value) of the regression equations: AER, number and location of apertures, wind speed, air-conditioning operation, indoor temperature, outdoor temperature, and relative humidity. The indoor concentrations of CO, PAH, NO, and NO x were highly correlated with the corresponding outdoor concentrations. The indoor benzene concentrations showed only moderate correlation with outdoor benzene levels, possibly due to a weak indoor source. Indoor formaldehyde concentrations always exceeded outdoor levels, and the correlation between indoor and outdoor concentrations was not statistically significant, indicating the presence of a strong indoor source.

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Continuous measurements of air change rates in an occupied house for 1 year: The effect of temperature, wind, fans, and windows

Cited by 228 publications

References 15 publications

Assessment of users' responses to air change rates in free running office buildings

Assessment of users' responses to air change rates in free running office buildings

Influence of environmental temperature on risk of gestational diabetes

A pilot study using scripted ventilation conditions to identify key factors affecting indoor pollutant concentration and air exchange rate in a residence

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