Size distribution and gas/particle partitioning of organophosphorus flame retardants in indoor and outdoor air of...

Organophosphorus flame retardants (OPFRs) pollution is an escalating issue, particularly in industrial environments. This study investigated the distribution of OPFRs in paired gaseous and size-resolved particulate samples collected in garment factories. Tris (chloroisopropyl) phosphate (TCIPP), tris (2-chloroethyl) phosphate (TCEP), and tris (isobutyl) phosphate (TIBP) were the dominant OPFRs. The total concentrations of the seven homologs of OPFRs (Σ₇OPFRs) in indoor air ranged from 18.5 to 308 ng/m³, with higher levels observed in warehouses (median: 149 ng/m³) and workshops (median: 87.5 ng/m³). In comparison, the concentration of Σ₇OPFRs in outdoor environments is only 1/4 to 1/2 of that in indoor environments. Influenced by temperature or humidity, the concentration of Σ₇OPFRs during non-heating seasons is significantly higher than during heating seasons. Notably, OPFRs are primarily distributed in the particulate phase rather than gas phase. OPFRs tend to enrich in coarse particles (aerodynamic diameter >2.5 μm) in textile workshop. Furthermore, fabrics have been identified as a significant OPFRs source in these environments. This study utilized the Harner-Bidleman and Li-Ma-Yang models to predict the gas/particle (G/P) partitioning. The Li-Ma-Yang model was successfully used to predict the G/P distribution of high molecular weight OPFRs. For low molecular weight OPFRs, the larger the particle size range, the closer the log K_P is to the model's prediction. However, the monitoring results consistently exceeded the predicted values. The inhalation exposure assessment revealed that the exposure risk for workers in warehouses and workshops is higher than that for office workers. The deposition flux of OPFRs in different regions of the human respiratory tract is size-dependent. This study fills the data gap on OPFRs in garment factories.