Occurrence and source apportionment of atmospheric halogenated flame retardants in Lhasa City in the Tibetan Plateau, China.

Active air samples were collected in Lhasa, one of the highest cities in the world (3650m above sea level) located in the Tibetan Plateau, and were analyzed for 38 halogenated flame retardants (HFRs), including polybrominated diphenyl ethers (PBDEs), non-PBDE brominated flame retardants (NBFRs) and dechlorane plus (DPs). The median concentrations of PBDEs, NBFRs and DPs were 40, 23 and 0.21pg/m, respectively. Correlation analysis indicated the common source and/or similar environmental behavior for several HFRs. The Clausius-Clapeyron equation was applied to diagnose the sources of lower molecular weight HFRs (LMW-HFRs), which suggested that the gaseous LMW-HFRs at Lhasa were more controlled by regional or long-range atmospheric transport rather than the temperature-driven evaporation from local contaminated surfaces. Finally, the potential source contribution function model was applied to assess the influences of air parcels on the atmospheric concentrations of HFRs in Lhasa, which suggested that the sources of higher molecular weight HFRs (HMW-HFRs) were mostly originated from local emissions, while the others were originated from long-range atmospheric transport.