Concentration and seasonal variation of halogenated flame retardants at a CAWNET background site in central China

Abstract

64 pairs of air samples (gas and particle phases) were collected using a high volume air sampler from March 2012 to March 2013 at Jinsha (JSH), a regional background China Atmosphere Watch Network (CAWNET) site in central China. Sixteen halogenated flame retardants (HFRs) were investigated, viz., eight polybrominated diphenyl ethers (PBDEs), six alternative brominated flame retardants (ABFRs), and two Dechlorane Plus congeners (DPs). The average atmospheric concentrations of the PBDEs, ABFRs, and DPs were 5.57 ± 3.08, 60.94 ± 44.24, and 2.54 ± 2.55 pg m –3 , respectively. BDE-209 and DBDPE were the dominant HFRs, which is consistent with their wide use in China. The atmospheric concentrations of the other HFRs were low, reflecting that these compounds are not widespread in China. The average ratio of the syn-DP to the total DP was 0.54 ± 0.10, which is higher than that of the commercial products. This implies DPs are residual compounds that were released during the historic use of commercial products. The gaseous concentration and temperature dependence displayed negative and steep slopes for BDE-28, BDE-47, and PBEB, which suggests a significant influence from local re-evaporation. The positive and steep slopes for BDE-99, BDE-183, and TBB indicate that long-range atmospheric transport controls their gaseous concentrations. The elevated concentrations of particle-bound HFRs observed during winter at JSH may be due to the low temperatures, and air masses from northern China. The gas-particle distribution of BDE-209 and DBDPE showed that these compounds mainly exist in the particulate phase. Their particular concentrations were not sensitive to changes in temperature but were influenced by air masses or local advection. It was discovered that the sources of BDE-209 may be related to e-waste emissions in the upwind area during summer and autumn.