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Residential indoor and outdoor coarse particles and associated endotoxin exposures
Wheeler, Amanda J. Dobbin, Nina A. Lyrette, Ninon Wallace, Lance Foto, Mark Mallick, Ranjeeta Kearney, Jill Van Ryswyk, Keith Gilbert, Nicolas L. Harrison, Ian
Wheeler, Amanda J.
Dobbin, Nina A.
Lyrette, Ninon
Wallace, Lance
Foto, Mark
Mallick, Ranjeeta
Kearney, Jill
Van Ryswyk, Keith
Gilbert, Nicolas L.
Harrison, Ian
Abstract
There is a growing body of evidence demonstrating that coarse particles (PM10–2.5) have detrimental impacts upon health, especially for respiratory effects. There are limited data available for indoor residential exposures. Some data exist regarding the composition of this PM size fraction with emphasis on crustal elements and biological components. This study includes data from 146 homes sampled in Regina, Saskatchewan (SK) where 5-day integrated concurrent monitoring of indoor and outdoor coarse particles was conducted during the winter and summer of 2007. The coarse particle filters were subsequently analysed for endotoxin content to determine the contribution of this compound. Winter indoor geometric mean concentrations of coarse particles exceeded outdoor concentrations (3.73 μg m−3 vs 2.49 μg m−3; paired t-test p < 0.0001); however the reverse was found in summer (4.34 μg m−3 vs 8.82 μg m−3; paired t-test p < 0.0001). Linear regression indicated that winter predictors of indoor coarse particles were outdoor coarse particles, ventilation and presence of at least two or more occupants. During the summer, increased use of central air conditioning was associated with reduced coarse particles, while smoking and the presence of two or more occupants resulted in increased coarse particles. Endotoxin concentrations (EU μg−1) were lower indoors than outdoors in both seasons. Spatial variability of ambient coarse particles was assessed to determine the suitability of using a single monitoring station within a city to estimate exposure. The coefficients of variation between homes sampled simultaneously and the central monitoring station were calculated (median COV in summer = 15% and winter = 24%) and showed significant variability by week, especially during the summer months, suggesting a single site may be insufficient for characterizing exposure. Future studies should consider daily measurements per home to understand shorter term exposures and day to day variability of these pollutants.
Keywords
coarse particles, endotoxin, indoor air quality, spatial variability
Date
2011
Type
Journal article
Journal
Atmospheric Environment
Book
Volume
45
Issue
39
Page Range
7064-7071
Article Number
ACU Department
Mary MacKillop Institute for Health Research
Faculty of Health Sciences
Faculty of Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
License
All rights reserved
File Access
Controlled