Bioavailability and regional transport of PM2.5 during heavy haze episode in typical coal city site of Fenwei Plain, China.

ABSTRACT

Despite the decrease in anthropogenic emissions, haze episodes were still frequent in the Fenwei Plain, which was identified as one of the three key areas for air pollution control. Herein, PM2.5 samples were collected to investigate the influence of festival effect during the Chinese Spring Festival from February 2rd to 13th, 2019, in Linfen on the Fenwei Plain. The characteristics of element pollution, enrichment factor, source apportionment, regional transport of PM2.5, and health risk assessment were discussed. Meanwhile, the simulated lung fluid method (SLF) was carried out to accurately assess the inhalation risks of heavy metals (HMs). Results indicated that the average concentration of PM2.5 was 195.6 µg·m-3 during the studying period. Road fugitive dust (15.6%), firework burning source (25.6%), industrial emission (30.5%), and coal combustion (28.3%) were identified by positive matrix factorization (PMF) modeling. Using the HYSPLIT trajectory model, air masses from the central Shaanxi, southern Hebei, and northern Henan were the dominant transport paths during the Spring Festival, which contributed 21.9 and 41.2% of total trajectories, respectively. The findings that high PSCF and CWT levels were found in central Shaanxi, southern Hebei, and northern Henan were confirmed. The SLF mean bioaccessibility (%) of the solubility of particulate metals was in order of Mn > Ni > Sb > Ba > Zn > Pb > Cr. However, the carcinogenic risk value of Cr was the highest, exceeding the maximum acceptable risk. The present study provided important information for further analyzing the air pollution cause of Fenwei Plain.