Levels, isomer profiles and chiral signatures of particle-bound hexabromocyclododecanes in ambient air around Shanghai, China

► Five HBCD diastereoisomers (α-, β-, γ-, δ- and ɛ-) were investigated in this study. ► δ-HBCD was detected in air with higher percentages than technical products. ► HBCDs in air from industrial area showed statistically higher level than urban sites. ► Domination of α-HBCD in urban areas suggested the occurrence of isomer conversion. ► Chiral signatures showed enantioselective enrichment of (−)-α-HBCD in air of Shanghai.