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Abstract In this study, levels of 14 organophosphate flame retardants (OPEs) were measured in 101 indoor dust samples collected from dormitories, residential homes, and offices in Beijing, China. In addition, paired air samples were also analyzed to evaluate any correlation between OPE levels in air and that in corresponding dust samples. The Σ 14 OPEs levels substantially varied between individual samples. Thereinto, significantly higher OPE levels were found in dust samples from office (mean value: 14 μg g–1), comparing to that in dust samples from residential homes (mean value: 5.9 μg g–1) and dormitories (mean value: 6.9 μg g–1). Congener profiles of OPEs in dust samples from different microenvironments indicated that tris (2-chloroethyl) phosphate (TCEP) was the dominant OPE in the office samples, followed by tris (2-chloroisopropyl) phosphate (TCPP). In contrast, TCPP was the dominant OPE in the residential home and dormitory samples, followed by TCEP. The mean concentration (range) of Σ 14 OPEs in the 15 air samples was 5.2 (1.0–20) ng m–3, and TCPP was the dominated congener in these samples. The concentration of TCEP and TCPP in air was positively correlated with that in corresponding indoor dust, and OPEs with highly saturated vapor pressures have higher fractions in the air than that in the dust. The estimated daily intakes through dust ingestion, dermal absorption, and inhalation indicated that the exposure to OPEs in indoor environments do not result in significant health risk for the general population in Beijing. Graphical abstract fx1 Highlights • OPEs levels were higher in dusts from offices than homes and dormitories. • Chlorinated TCEP and TCPP were the dominant OPEs in dusts. • The fraction of TCPP was higher in air than in dust. • EDIs were present at three orders of magnitude lower than the RfDs. [ABSTRACT FROM AUTHOR]

• A 3-D model of crack asphalt pavement after overlaid was established based on XFEM. • The SIF was selected as the index to evaluate crack propagation trends. • The influences of overlay thickness and different types of cracks were considered. • The temperature and traffic loading were applied through sequential coupling. The asphalt overlay is a major maintenance strategy to improve the performance of cracked pavement. However, the crack would propagate upwards and eventually reach to the limit of service life. The potential of the crack propagation of overlaid pavement with cracks will be the key point to evaluate the overlay strategy and the pavement service life. In this study, the Extended Finite Element Method (XFEM) in ANSYS was utilized as the analysis engine to establish the pavement finite model with cracks. Taking Beijing area as example, the transient thermal analysis module was used to construct the 24-hour temperature field in winter. The stress intensity factor (SIF) was adopted as the index to evaluate the effectiveness of the overlay thickness, the length and inclination of crack, as well as temperature under traffic loading. The results indicated that the sliding crack is the major fracture mode for pavement under pure vehicle loading, while the mixed mode of opening and sliding mode changes to be the major fracture mode for pavement under low temperature. The geometric property of existing crack has a significant influence on the critical loading position and peak value of SIF in overlaid pavement. And the promotion effect of increasing the overlay thickness on preventing crack propagation was gradually weakening. The achievement in this study will bring an insight into crack propagation for pavement overlay paving as well as the pavement maintenance. [ABSTRACT FROM AUTHOR]