This study estimates infiltration factors (F-inf) and ambient personal exposure factors (F-pex) for fine particulate matter (PM2.5) in two Chinese megacities, and constructs predictive models to explore their determinants. Personal-indoor-outdoor PM2.5 filter samples were collected for five consecutive days from 33 residences (of retired adults) in Nanjing (NJ) and Beijing (BJ), China, in both the non-heating season (NHS) and the heating season (HS). Elemental sulfur in filter deposits was determined by energy-dispersive X-ray fluorescence for PM2.5 F-inf and F-pex estimations. Season-specific models developed by stepwise multiple linear regression were evaluated using R-2 and root mean square error (RMSE). The median [interquartile range (IQR)] of F-inf varied from 0.76 (0.15) in the HS to 0.93 (0.11) in the NHS in NJ; and from 0.67 (0.16) to 0.86 (0.12) in BJ. Similarly, F-pex was significantly higher during the NHS [NJ: 0.95 (0.07); BJ: 0.89 (0.14)] than during the HS [NJ: 0.76 (0.17); BJ: 0.67 (0.11); p <0.0001]. Common predictors of F-inf and F-pex included window opening behaviors, meteorological variables, and building age. Moreover, air conditioning and distance to the nearest major road had an influence on F-inf, while predictors of F(pex )were more related to human behavior and activity (e.g., time spent outdoors and transportation). The models accounted for 35.4%-68.1% (RMSE: 0.065-0.101) and 41.6%-77.0% (RMSE: 0.033-0.103) of the variance in F-inf and F-pex respectively. By indicating the determinants of F-inf and F-pex these models can improve ambient PM2.5 exposure assessment and reduce exposure misclassification.
Estimation of PM2.5 infiltration factors and personal exposure factors in two megacities, China
Li, N., Liu, Z., Li, Y., Li, N., Chartier, R., Mcwilliams, A., Chang, J., Wang, Q., Wu, Y., Xu, C., & Xu, D. (2019). Estimation of PM2.5 infiltration factors and personal exposure factors in two megacities, China. Building and Environment, 149(7), 297-304. https://doi.org/10.1016/j.buildenv.2018.12.033