Temporal and spatial distribution of novel brominated flame retardants in atmosphere of the Beijing-Tianjin-Hebei region, China

The occurrence and spatio-temporal distribution of atmospheric novel brominated flame retardants (NBFRs) were studied across five sampling sites in the Beijing-Tianjin-Hebei (BTH) region over a whole year. By collecting samples (gas and particle) with a high-volume active air sampler (HV-AAS), nine NBFRs were analyzed and the sum concentrations ranged from 1.65 to 344 pg/m³, with the highest value found in the urban sampling site in Shijiazhuang City. Decabromodiphenylethane (DBDPE) was the predominant congener, which accounted for 60% of ∑₉NBFRs on average, while it was 90% of ∑₉NBFRs in the rural site and significantly higher than those observed in the urban sites (one-way ANOVA, p < 0.05). The levels of particle-bound NBFRs were significantly correlated with the variation of total suspended particulates (TSP) and temperature (p < 0.01), indicating their evident impact on the spatio-temporal distribution of NBFRs. Moreover, a significantly positive correlation was observed between the concentrations of 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and bis (2-ethyl-1-hexyl) tetrabromophthalate (BEH-TEBP) (p < 0.01). Monocyclic brominated flame retardants (including PBBz, PBT, PBEB, HBB and TBP-DBPE) were correlated with each other (p < 0.01) in both gas and particle phase, suggesting their co-occurrence and the similar source in the environment. The gas-particle partitioning behavior was well predicted by the Li-Jia Empirical Model, and the results indicated that the target NBFRs did not reach the equilibrium state in air. This is one of very few studies revealed the spatio-temporal distribution of atmospheric NBFRs in the BTH region.