Halogenated flame retardants (HFRs) and water-soluble ions (WSIs) in fine particulate matter (PM2.5) in three regions of South China

Abstract

Halogenated flame retardants (HFRs) and water-soluble ions (WSIs) were investigated in fine particulate matter (PM2.5) collected from an urban site, a rural e-waste recycling (e-waste) site, and a background site in South China. Generally, the WSI concentrations were highest at the e-waste site and comparable at the other sites and secondary species (SO42−, NH4+, and NO3−) were dominant components at the three sites. The compositions and seasonal variations of WSIs at the e-waste site were distinct from those in the urban and background areas suggesting significant influence of e-waste recycling on PM2.5 components. Polybrominated diphenyl ethers (PBDEs) dominated the HFRs in PM2.5 from the e-waste site, and their concentrations (median = 883 pg/m3) were significantly higher than those at the urban (375 pg/m3) and background site (52.4 pg/m3). However, novel decabromodiphenyl ethane (DBDPE) was the primary HFRs in the urban air, with noticeably elevated concentrations (median = 356 pg/m3) compared to those in the other two areas (medians = 62.3 and 5.09 pg/m3). The composition profiles of HFRs in the background air followed those in the e-waste areas, with substantial contributions of legacy chemicals. This was explained by the prevailing NE wind, which favored atmospheric transport of HFRs from the e-waste recycling area to the background area. Correlation analysis showed that most HFRs in the urban air are associated with Cl−, implying an industrial emission sources. In the e-waste area, HFRs are associated with organic and elemental carbons (OC and EC) and K+, confirming a common source of e-waste recycling. Significant correlations between HFRs and EC and Cl− in the background air suggest that their occurrence in this region was attributed to both the e-waste and urban areas.