Health risk assessment of exposure to polybrominated diphenyl ethers (PBDEs) contained in residential air particulate and dust in Guangzhou and Hong Kong

Polybrominated diphenyl ethers (PBDEs) were measured in air particulate PM2.5 (less than 2.5 μm), TSP (Total Suspend Particle) and dust samples from different households of two major urban centers of Pearl River Delta (PRD). ∑PBDEs in PM2.5 of households in Guangzhou (GZ) (52.9-2.03 × 103 pg m−3 mean 239 pg m−3) were significantly higher than Hong Kong (HK) (0.25-160 pg m−3, mean 43.8 pg m−3). Higher ∑PBDEs occurred in indoor TSP, ranging between 117 and 1.14 × 103 pg m−3, with a median of 333 pg m−3. BDE-209 was the largest contributor to PBDEs contained in household dust, PM2.5 and TSP samples of GZ. Among the particles in household environment, PM2.5 accumulated the highest PBDEs, especially BDE-209. The constant Cparticle/Cdust values suggested that sorption is the dominant mechanism through which PBDEs are associated with settled dust and airborne particles. PBDEs were fairly uniform from urban sites to suburban sites, indicating the predominant indoor sources of PBDEs. Compared with indoor PM2.5, indoor dust ingestion made an important contribution of particle associated PBDEs exposure for adults (25 years old) and toddlers (1-2 years old). Non-dietary exposure dominated total PBDEs exposure, accounting for 91.8-99.0% exposure dose for toddlers and 45.1-82.2% for adults. Dust ingestion (69.3-96.1%) was the predominant PBDEs exposure route for toddlers.