Particle-phase concentrations and sources of legacy and novel flame retardants in outdoor and indoor environments across Spain

Abstract

Levels of particle-phase legacy polybrominated diphenyl ethers (PBDEs), and novel brominated and chlorinated flame retardants, such as decabromodiphenyl ethane (DBDPE) and Dechlorane Plus (DP), were measured in ambient outdoor air, indoor workplace air and indoor dust, in different locations across Spain. PBDE concentrations were generally higher in outdoor ambient air samples than in indoor air, ranging between 1.18 and 28.6 pg m−3, while DP was the main flame retardant (FR) in indoor air (2.90–42.6 pg m−3). A different behavior of legacy versus novel FRs was observed in all the environments and matrices considered, which seemed to indicate a progressive replacement of the former. Although the emission sources could not be fully identified, certain evidences suggested that high outdoor PBDE concentrations could be associated with old goods in landfills and recycling centers, while high indoor DP concentrations were linked to the presence of new electronic devices. A direct impact of land use on outdoor atmospheric DP concentrations was observed, with DP concentrations correlating with high density of buildings within a city. In addition, DP concentrations outdoors correlated with inorganic species with FR properties (e.g., Cr, Cu). Significant differences in the fraction of anti-DP to the total DP (Fanti ratio) were observed between indoor air (PM2.5) and dust (PM10), which could be related with: a) a dependence on particle size, suggesting a higher relative abundance of the anti-isomer in PM10 than in PM2.5, while similar concentrations were recorded for the syn-isomer; b) a higher deposition rate of the anti-isomer compared to the syn-isomer; and/or c) a more accentuated preferential degradation of the anti-isomer linked to artificial light or other agents coexisting in the air. The detectable presence of all the FR families analyzed in indoor air and dust points to the importance of monitoring these compounds in order to minimize human exposure.