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Linking in-vehicle ultrafine particle exposures to on-road concentrations
Abstract For traffic-related pollutants like ultrafine particles (UFP), a significant fraction of overall exposure occurs within or close to the transit microenvironment. Therefore, understanding exposure to these pollutants in such microenvironments is crucial to accurately assessing overall UFP exposure. The aim of this study was to develop models for predicting in-cabin UFP concentrations if roadway concentrations are known, quantifying the effect of vehicle characteristics, ventilation settings, driving conditions and air exchange rates (AER). Particle concentrations and AER were measured in 43 and 73 vehicles, respectively, under various ventilation settings and driving speeds. Multiple linear regression (MLR) and generalized estimating equation (GEE) regression models were used to identify and quantify the factors that determine inside-to-outside (I/O) UFP ratios and AERs across a full range of vehicle types and ages. AER was the most significant determinant of UFP I/O ratios, and was most strongly influenced by ventilation setting (recirculation or outside air intake). Further inclusion of ventilation fan speed, vehicle age or mileage, and driving speed explained greater than 79% of the variability in measured UFP I/O ratios.
Graphical abstract Display Omitted Highlights ► Significant overall ultrafine particle (UFP) exposure occurs in vehicles. ► In-vehicle exposures depend on inside-to-outside UFP ratios (I/O). ► At outside air setting, I/O is determined mostly by fan strength. ► Under recirculation, I/O is determined by vehicle age and speed. ► Fleet-wide UFP exposure varies 10-fold.
Linking in-vehicle ultrafine particle exposures to on-road concentrations
Abstract For traffic-related pollutants like ultrafine particles (UFP), a significant fraction of overall exposure occurs within or close to the transit microenvironment. Therefore, understanding exposure to these pollutants in such microenvironments is crucial to accurately assessing overall UFP exposure. The aim of this study was to develop models for predicting in-cabin UFP concentrations if roadway concentrations are known, quantifying the effect of vehicle characteristics, ventilation settings, driving conditions and air exchange rates (AER). Particle concentrations and AER were measured in 43 and 73 vehicles, respectively, under various ventilation settings and driving speeds. Multiple linear regression (MLR) and generalized estimating equation (GEE) regression models were used to identify and quantify the factors that determine inside-to-outside (I/O) UFP ratios and AERs across a full range of vehicle types and ages. AER was the most significant determinant of UFP I/O ratios, and was most strongly influenced by ventilation setting (recirculation or outside air intake). Further inclusion of ventilation fan speed, vehicle age or mileage, and driving speed explained greater than 79% of the variability in measured UFP I/O ratios.
Graphical abstract Display Omitted Highlights ► Significant overall ultrafine particle (UFP) exposure occurs in vehicles. ► In-vehicle exposures depend on inside-to-outside UFP ratios (I/O). ► At outside air setting, I/O is determined mostly by fan strength. ► Under recirculation, I/O is determined by vehicle age and speed. ► Fleet-wide UFP exposure varies 10-fold.
Linking in-vehicle ultrafine particle exposures to on-road concentrations
Hudda, Neelakshi (author) / Eckel, Sandrah P. (author) / Knibbs, Luke D. (author) / Sioutas, Constantinos (author) / Delfino, Ralph J. (author) / Fruin, Scott A. (author)
Atmospheric Environment ; 59 ; 578-586
2012-05-14
9 pages
Article (Journal)
Electronic Resource
English
Ultrafine particle concentrations and exposures in seven residences in northern California
| Wiley | 2011
Ultrafine particle concentrations and exposures in seven residences in northern California
| Online Contents | 2011