Pollution Characteristics, Influencing Factors and Health Risk Assessments of Mercury in Atmospheric PM2.5 from Xinxiang, China

This study characterized mercury (Hg) associated with PM2.5 in Xinxiang, China, using samples collected throughout 2015, providing a historical perspective on its temporal variation, relationships with meteorological conditions, gaseous pollutants, carbon components, water-soluble ions, and trace elements. The annual mean mercury concentration in PM2.5 in Xinxiang was 0.399 ng/m3. Significant seasonal differences were observed (p < 0.001), with Hg concentrations in winter significantly higher than those in other seasons. The mercury concentration in PM2.5 during the heating period was higher than that in the non-heating period. Mercury was significantly positively correlated with SO2, CO, PM2.5, OC, EC, Cl−, Zn, and Ca, and negatively correlated with temperature, O3, and V (p < 0.05). The non-carcinogenic risk assessment showed that ingestion was the dominant exposure pathway, followed by dermal contact and inhalation. The mean hazard index was 2.06 × 10−3 for children and 8.46 × 10−4 for adults, both well below 1, suggesting a low estimated non-carcinogenic risk under the exposure assumptions used in this assessment.