Summary: | A city with light industry in China was selected for the study of the chemical characteristics of PM<sub>2.5</sub> and to assess its impact on inhalation health risks. During the period from May 2017 to February 2018, a total of 382 PM<sub>2.5</sub> filter samples were collected across four seasons (15–20 days for each season). The results showed that the daily average PM<sub>2.5</sub> concentration ranged from 21 to 255 µg/m<sup>3</sup>, with an annual average of 73 ± 49 µg/m<sup>3</sup>. SO<sub>4</sub><sup>2−</sup>, NO<sub>3</sub><sup>−</sup>, NH<sub>4</sub><sup>+</sup>, and organic matter (OM) were the dominant components, accounting for 13%, 20%, 11%, and 20% of annual PM<sub>2.5</sub> mass loading, respectively. Compared with the clean periods, the meteorology of the pollution periods were mostly characterized by high relatively humidity, high temperature, and low wind speeds. Based on positive matrix factorization (PMF), the major source of PM<sub>2.5</sub> was identified as secondary aerosols, contributing 28% and 49% on clean days and polluted days, respectively. The health risk assessment of heavy metals showed that non-carcinogenic hazard is not expected to occur, while Cr contributed the highest cancer risk. This study is helpful for the advancement of our scientific understanding of PM<sub>2.5</sub> pollution and its impact on health in cities with light industries.
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