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Comparative Study
. 2019 Mar;29(2):231-241.
doi: 10.1111/ina.12533. Epub 2019 Jan 25.

The Fort Collins commuter study: Variability in personal exposure to air pollutants by microenvironment

Kirsten Koehler  1 , Nicholas Good  2 , Ander Wilson  3 , Anna Mölter  2 , Brianna F Moore  2 , Taylor Carpenter  2 , Jennifer L Peel  2 , John Volckens  2   4
Affiliations
Comparative Study

The Fort Collins commuter study: Variability in personal exposure to air pollutants by microenvironment

Kirsten Koehler et al. Indoor Air. 2019 Mar.

Abstract

This study investigated the role of microenvironment on personal exposures to black carbon (BC), fine particulate mass (PM2.5 ), carbon monoxide (CO), and particle number concentration (PNC) among adult residents of Fort Collins, Colorado, USA. Forty-four participants carried a backpack containing personal monitoring instruments for eight nonconsecutive 24-hour periods. Exposures were apportioned into five microenvironments: Home, Work, Transit, Eateries, and Other. Personal exposures exhibited wide heterogeneity that was dominated by within-person variability (both day-to-day and between microenvironment variability). Linear mixed-effects models were used to compare mean personal exposures in each microenvironment, while accounting for possible within-person correlation. Mean personal exposures during Transit and at Eateries tended to be higher than exposures at Home, where participants spent the majority of their time. Compared to Home, mean exposures to BC in Transit were, on average, 129% [95% confidence interval: 101% 162%] higher and exposures to PNC were 180% [101% 289%] higher in Eateries.

Keywords: air pollution; indoor air; microenvironment; personal exposure; traffic-related air pollution; ultrafine particles.

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Conflict of interest statement

The authors have no conflict of interest to declare.

Figures

Figure 1:
Figure 1:
GPS trace for one sampling day for a single participant. Bar color denotes the pollutant (BC in black or PM2.5 in blue) and bar height denotes the relative concentration. The red star denotes the participant’s home location and the green star denotes the participant’s work location. The concentrations of BC and PM2.5 over time are shown in the top panel. The shading indicates the microenvironment in which the participant was located during that time period (Home in red; Work in green; Transit in gray; Eatery in blue; and Other in orange). Natural areas are denoted in green on the map.
Figure 2:
Figure 2:
Violin plots overlain with boxplots of time-weighted average concentration in each microenvironment and over 24-hours for BC, PM2.5, CO, and PNC for all participants. The top and bottom line of each box shows the 25th and 75th percentile of exposures and the middle line shows the median. Whiskers on the boxplots show 95% coverage of the data; the axis is broken along the line to show outliers. Asterisks indicate that exposures in a given microenvironment were significantly different than in the Home microenvironment, when accounting for within subject autocorrelation.
Figure 3:
Figure 3:
Left: the contribution of the five microenvironments to mean exposures of PM2.5 mass (average for each participant; μg m−3). Mean exposures to PM2.5 by microenvironment for all eight sampling days for a single participant are shown in the inset. Right: 24-hour average PM2.5 exposures for all sampling days by participant. Participants are ordered from lowest to highest in terms of integrated PM2.5 exposure.
Figure 4:
Figure 4:
Violin plots overlain with boxplots of mass-time exposure ratios in each microenvironment for BC, PM2.5, CO, and PNC. The top and bottom line of each box shows the 25th and 75th percentile of exposures and the middle line shows the median. Whiskers on the boxplots show 95% coverage of the data; the axis is broken along the line to show outliers. The dashed line indicates a value of 1, meaning that the fraction of time in a microenvironment equals the fraction of daily integrated exposure in that microenvironment.
Figure 5:
Figure 5:
Scatter plot of mean 24-hour personal exposures and mean 24-hour ambient concentrations for PM2.5 and CO.
See this image and copyright information in PMC

References

    1. Cohen AJ, Brauer M, Burnett R, et al. Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: an analysis of data from the Global Burden of Diseases Study 2015. Lancet 2017;389(10082):1907–1918. - PMC - PubMed
    1. Klepeis NE, Nelson WC, Ott WR, et al. The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants. J Expo Anal Env Epid 2001;11(3):231–252. - PubMed
    1. Meng QY, Spector D, Colome S, Turpin B. Determinants of indoor and personal exposure to PM(2.5) of indoor and outdoor origin during the RIOPA study. Atmos Environ 2009;43(36):5750–5758. - PMC - PubMed
    1. Meng QY, Williams R, Pinto JP. Determinants of the associations between ambient concentrations and personal exposures to ambient PM2.5, NO2, and O-3 during DEARS. Atmos Environ 2012;63:109–116.
    1. Abt E, Suh HH, Catalano P, Koutrakis P. Relative contribution of outdoor and indoor particle sources to indoor concentrations. Environ Sci Technol 2000;34(17):3579–3587.

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