Performance of a microenviromental model for estimating personal NO2 exposure in children

TY - JOUR

T1 - Performance of a microenviromental model for estimating personal NO2 exposure in children

AU - Moelter, Anna

AU - Lindley, Sarah

AU - de Vocht, Frank

AU - Agius, Raymond

AU - Kerry, Gina

AU - Johnson, Katy

AU - Ashmore, Mike

AU - Terry, Andrew

AU - Dimitroulopoulou, Sani

AU - Simpson, Angela

PY - 2012/5

Y1 - 2012/5

N2 - A common problem in epidemiological studies on air pollution is exposure misclassification, because investigators often assume exposure is equivalent to outdoor concentrations at participants' homes or at the nearest urban monitor.The aims of this study were: (1) to develop a new microenvironmental exposure model (MEEM), combining time-activity data with modelled outdoor and indoor NO2 concentrations; (2) to evaluate MEEM against data collected with Ogawa (TM) personal samplers (OPS); (3) to compare its performance against datasets typically used in epidemiological studies.Schoolchildren wore a personal NO2 sampler, kept a time-activity diary and completed a questionnaire. This information was used by MEEM to estimate individuals' exposures. These were then compared against concentrations measured by OPS, modelled outdoor concentrations at the children's home (HOME) and concentrations measured at the nearest urban monitoring station (NUM).The mean exposure predicted by MEEM (mean = 19.6 mu g m(-3)) was slightly lower than the mean exposure measured by OPS (mean = 20.4 mu g m(-3)). The normalised mean bias factor (0.01) and normalised mean absolute error factor (0.25) suggested good agreement. In contrast, the HOME (mean = 31.2 mu g m(-3)) and NUM (mean = 28.6 mu g m(-3)) methods overpredicted exposure and showed systematic errors.The results indicate that personal exposure can be modelled by MEEM with an acceptable level of agreement, while methods such as HOME and NUM show a poorer performance. (C) 2012 Elsevier Ltd. All rights reserved.

AB - A common problem in epidemiological studies on air pollution is exposure misclassification, because investigators often assume exposure is equivalent to outdoor concentrations at participants' homes or at the nearest urban monitor.The aims of this study were: (1) to develop a new microenvironmental exposure model (MEEM), combining time-activity data with modelled outdoor and indoor NO2 concentrations; (2) to evaluate MEEM against data collected with Ogawa (TM) personal samplers (OPS); (3) to compare its performance against datasets typically used in epidemiological studies.Schoolchildren wore a personal NO2 sampler, kept a time-activity diary and completed a questionnaire. This information was used by MEEM to estimate individuals' exposures. These were then compared against concentrations measured by OPS, modelled outdoor concentrations at the children's home (HOME) and concentrations measured at the nearest urban monitoring station (NUM).The mean exposure predicted by MEEM (mean = 19.6 mu g m(-3)) was slightly lower than the mean exposure measured by OPS (mean = 20.4 mu g m(-3)). The normalised mean bias factor (0.01) and normalised mean absolute error factor (0.25) suggested good agreement. In contrast, the HOME (mean = 31.2 mu g m(-3)) and NUM (mean = 28.6 mu g m(-3)) methods overpredicted exposure and showed systematic errors.The results indicate that personal exposure can be modelled by MEEM with an acceptable level of agreement, while methods such as HOME and NUM show a poorer performance. (C) 2012 Elsevier Ltd. All rights reserved.

KW - RISK-ASSESSMENT

KW - AMBIENT AIR-POLLUTION

KW - Schoolchildren

KW - UK HOMES

KW - SCHOOL-CHILDREN

KW - NITROGEN-DIOXIDE

KW - EPIDEMIOLOGIC RESEARCH

KW - INDOOR

KW - LAND-USE REGRESSION

KW - INTRAURBAN VARIABILITY

KW - Exposure

KW - NO2

KW - Microenvironments

KW - Personal samplers

KW - SPATIAL VARIABILITY

KW - Modelling

UR - http://www.scopus.com/inward/record.url?scp=84857789231&partnerID=8YFLogxK

U2 - 10.1016/j.atmosenv.2012.01.030

DO - 10.1016/j.atmosenv.2012.01.030

M3 - Article

SN - 1352-2310

VL - 51

SP - 225

EP - 233

JO - Atmospheric Environment

JF - Atmospheric Environment

ER -