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Inhalation exposure to flame retardants used as additives to minimize fire risk and plasticizers is ubiquitous in human daily activities, but has not been adequately assessed. To address this research gap, the present study conducted an assessment of human health risk for four age groups through inhalation exposure to size fractionated particle-bound and gaseous halogenated flame retardants (polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs)) and organophosphate esters (OPEs) at indoor and outdoor environments (school, office, and residence) in three districts of a megacity (Guangzhou, China). Results demonstrated that OPEs were the dominant components among all targets. Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels for all age groups. Gaseous OPEs contributed significantly greater than particle-bound compounds to daily intakes of all target compounds. Based on the different life scenarios, hazard quotient (HQ) and incremental life cancer risk (ILCR) from adults exposure to PBDEs and OPEs in indoor and outdoor settings were the greatest, followed by adolescents, children, and seniors. The estimated HQ and ILCR for all age groups both indoors and outdoors were lower than the safe level (HQ = 1 and ILCR = 10−6), indicating that the potential health risk for local residents in Guangzhou via inhalation exposure to atmospheric halogenated flame retardants and OPEs was low. Image 1 • Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels. • Daily intakes of gaseous OPEs were greater than particle-bound OPEs. • Inhalation exposure health risk for residents in Guangzhou to PBDEs and OPEs was low. Comprehensive investigation of indoor and outdoor polybrominated diphenyl ethers and organophosphate esters are conducted to provide new insight in risk assessment of human inhalation exposure to atmospheric halogenated flame retardants and plasticizers in an urban zone. [ABSTRACT FROM AUTHOR]

Understanding particle size distribution and size-resolved gas-particle partitioning of semi-volatile organic compounds (SVOCs) is important for characterizing their fate in atmosphere. However, the size-resolved gas-particle partitioning characteristics of SVOCs has not been adequately considered. To address this issue, the present study collected gaseous and size-fractioned particulate samples both in and outside of schools, offices, and residences in three districts of different urbanization levels in a megacity, Guangzhou, South China during two seasons. Typical SVOCs, including 15 polycyclic aromatic hydrocarbons (PAHs), six organophosphate esters and seven phthalic acid esters were measured. Emission sources, physicochemical properties, and environmental conditions at the sampling sites considerably impacted the spatiotemporal distribution patterns and particle size distribution of target SVOCs. Not all observed gas-particle partition coefficients (K p) of target SVOCs were negatively correlated with subcooled liquid-vapor pressures (P L 0), probably because certain factors, such as the non-exchangeable part of the particle-bound SVOCs, were not considered in traditional gas-particle partition theories. Particle size was an important factor affecting gas-particle partitioning. Adsorption was the dominant mechanism for PAHs with high molecular weight in different particle modes. A new model was established to predict size-resolved K p of PAHs with high molecular weight based on P L 0 and particle size. [Display omitted] • Observed log K p of PAEs and OPEs were not well correlated with log P L 0. • Observed log K p of 3- and 4-rings PAHs were negatively related with log P L 0. • Adsorption was the dominant gas-particle partition mechanism of 3- and 4-rings PAHs. • Particle size affects gas-particle partitioning of semi-volatile organic compounds. • The established model greatly predicted size-resolved K p of 3- and 4-rings PAHs. [ABSTRACT FROM AUTHOR]

Atmospheric particle size distribution of polycyclic aromatic hydrocarbons (PAHs) in a typical e-waste recycling zone and an urban site (Guangzhou) in southern China featured a unimodal peak in 0.56–1.8 μm for 4–6 ring PAHs but no obvious peak for 2–3 ring PAHs at both sites. The atmospheric deposition fluxes of PAHs were estimated at 5.4 ± 2.3 μg m −2 d −1 in the e-waste recycling zone and 3.1 ± 0.6 μg m −2 d −1 in Guangzhou. In addition, dry and wet deposition fluxes of PAHs were dominated by coarse ( D p > 1.8 μm) and fine particles ( D p < 1.8 μm), respectively. Fine particles predominated the deposition of PAHs in the lung. The results estimated by incremental inhalation cancer risk suggested that particle-bound PAHs posed serious threat to human health within the e-waste recycling zone and Guangzhou. [ABSTRACT FROM AUTHOR]