Chemical Characteristics and Cytotoxicity to GC-2spd(ts) Cells of PM_2.5 in Nanjing Jiangbei New Area from 2015 to 2019

PM_2.5 is an air pollutant with complex components. After entering the body through respiration, PM_2.5 can not only cause respiratory diseases, but also break through the blood–testis barrier and influence the reproductive system. PM_2.5 with different components may result in different toxic effects. In the first five years of Nanjing Jiangbei New Area, industrial transformation would change the concentration and chemical fraction of PM_2.5 in the local environment to a certain extent. In this study, PM_2.5 collected in Nanjing Jiangbei New Area every autumn and winter from 2015 to 2019 was analyzed. PM_2.5 concentration generally decreased year by year. The large proportion of secondary inorganic ions indicated the presence of secondary pollution at the sampling site. PM_2.5 was mainly emitted from fossil fuel combustion and vehicle exhaust. The cytotoxicity of PM_2.5 samples was evaluated by PM_2.5 exposure to mouse spermatocytes (GC-2spd(ts) cells). Cell viability was relatively low in 2016 and 2018, and relatively high in 2017 and 2019. Reactive oxygen species levels and DNA damage levels followed similar trends, with an overall annual decrease. The cytotoxicity of PM_2.5 on GC-2spd(ts) cells was significantly correlated with water-soluble ions, water-soluble organic carbon, heavy metals and polycyclic aromatic hydrocarbons (p < 0.01). According to principal component analysis and multiple linear regression, fossil fuel combustion, secondary transformation of pollutants and construction dust were identified as the major contributors to cytotoxic effects, contributing more than 50%.