Organophosphorus flame retardants in wearable passive air samplers: Association with paired urinary levels and oxidative stress

Organophosphorus flame retardants and plasticizers (OPFRs) are widely used as additives in daily products, with increasing industrial production and environmental emissions. Airborne OPFRs can enter human body through inhalation, posing potential health risks. This study employed a wearable silicone-sorbent passive sampler to capture personal airborne OPFRs around participants ( n = 49) for external exposure and assessed their internal exposure levels via urine analysis. Twenty-five OPFRs were detected in the passive samplers, and 9 OPFRs and their metabolites were detected in their urine samples. The combined silicone-sorbent passive samplers effectively favored enrichment of OPFR diesters and chlorinated OPFR triesters (Cl-OPFRs). Triethyl phosphate and dibutyl phosphate were fully detected, followed by Cl-OPFRs (85.7%–95.9%) in the samplers. Notably, urinary levels of hydroxylated metabolite dibutyl 3-hydroxybutyl phosphate and hydrolyzed metabolite dicresyl phosphate were significantly associated with tributyl phosphate and tricresyl phosphate in the samplers, respectively, reflecting airborne exposure followed by metabolic transformation. Direct airborne exposure to diphenyl phosphate and bis (1,3-dichloropropan-2-yl) hydrogen phosphate were also indicated by significant associations. Furthermore, both external and internal OPFR exposure levels showed significant associations with urinary levels of oxidative stress biomarkers (OSBs) as well as cortisol and cortisone, while the associations for chlorinated OPFRs were only found for external exposure. These underscore potential risk to endocrine homeostasis and anti-inflammatory responses resulting from personal airborne exposure to OPFRs. • Portable silicone-sorbent passive sampler captured 25 organophosphorus flame retardants and plasticizers (OPFRs) in the ambient air. • Airborne exposure to OPFR diesters were significant associated with their urinary levels. • Urinary dicresyl phosphate and dibutyl 3-hydroxybutyl phosphate were significantly associated with their airborne precursors. • Airborne chlorinated OPFRs were associated with urinary oxidative stress biomarkers and typical steroid hormones.