Temporal variations of PM2.5-bound organophosphate flame retardants in different microenvironments in Beijing, China, and implications for human exposure

Abstract In the present study, the temporal distribution of PM 2.5 -bound organophosphate flame retardants (OPFRs) was comprehensively investigated in various indoor environments as well as outdoor air in Beijing, China over a one-year period. The mean concentrations of Σ 9 OPFRs were 22.7 ng m −3 and 1.40 ng m −3 in paired indoor and outdoor PM 2.5 , respectively. The concentrations of tri- n -butyl phosphate (TNBP), tris (2-chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCIPP) in indoor PM 2.5 were significantly correlated with those in outdoor PM 2.5 . For different indoor microenvironments, mean concentrations of Σ 9 OPFRs were in the order of office (29.0 ± 11.7 ng m −3 ) > home (24.0 ± 9.4 ng m −3 ) > dormitory (19.4 ± 4.9 ng m −3 ) > activity room (14.4 ± 3.1 ng m −3 ). TCIPP was the most abundant compound in the indoor PM 2.5 , followed by TCEP. Significantly higher concentrations of OPFRs were observed in indoor environments with more furnishing, electronics or other materials ( p 9 OPFRs in the activity room, dormitory, homes and outdoor sites generally increased in summer and heating seasons (November 2016 to February 2017). Significant correlations ( p 2.5 -bound OPFRs via inhalation among all age groups. This is one of the very few studies that have revealed the seasonal variation and human exposure of PM 2.5 -bound OPFRs in different microenvironments, which shed light on emission sources and fate of OPFRs and potential human exposure pathway.