Abstract: OBJECTIVE: To assess the toxicity pathway activation induced by PM_2.5 using data from Tox21 10K library based on the result of Ambient fine particulate matter-bound PAHs during heating period of 2017 in Shijiazhuang. METHODS: Particle samples were collected in Hebei Medical University where it is away from polluted industrial area. Concentrations of 16 US EPA priority PAHs were measured by GC-EI-MS. The deposition fractions of PM-bound PAHs in adult alveolar region of lung were determined by multiple-path particle dosimetry model. The potencies of PAHs in the AhR,Nrf2,p53 and NF-κB pathways were calculated using data from the Tox21 10K library. The assessment of risk from PM_2.5 exposure was based on the alveolar deposition fraction combined with the potency of PAHs activated toxicity pathway. RESULTS: The average concentration of benzo[a]pyrene was 9.13 ng/m³. Daily concentrations of the top three chemicals in PM-bound PAHs were benzo[b]fluoranthene,fluoranthene and pyrene,and their average concentrations were 22.88、17.86 and 14.31 ng/m³ respectively. The benzo[a]pyrene equality concentration was 17.74 ng/m³. And the NF-κB pathway was most likely activated by PM-bound PAHs during the heating period and the second one was the AhR pathway which was followed by Nrf2. The p53 pathway was the least activated. The corresponding activity-to-exposure ratio values were 1.97,1.71,0.58 and 0.28. CONCLUSION: PM-bound PAHs in Shijiazhuang might increase the risk of carcinogenesis via activation of the NF-κB and the AhR pathways.

Key words: fine particulate matter, polycyclic aromatic hydrocarbon, high throughput screening, toxicity pathway, risk assessment