Levels and inhalation health risk of neonicotinoid insecticides in fine particulate matter (PM2.5) in urban and rural areas of China

[Display omitted] •Neonicotinoid insecticides were almost exclusively found adsorbed to particulate matter in the atmosphere.•All PM2.5 samples contained at least two neonicotinoids.•Imidacloprid was detected at the highest concentrations, 4.33 – 1.13 × 102 pg m−3.•The contributions of THIM and CLO to inhalation exposure were dominant in Zhengzhou.•Rural children less than 6 years old had the highest inhalation daily dose, 91.0 pg kg−1 day−1. Neonicotinoid insecticide (NEO) concentrations in ambient fine particulate matter (PM2.5) and daily exposure via inhalation were investigated during spring and fall in an urban area in Beijing and in urban and rural areas of Zhengzhou, Henan Province, China. Four NEOs, including imidacloprid, acetamiprid, thiamethoxam and clothianidin, were assessed using a QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction procedure coupled to liquid chromatography–tandem mass spectrometry. Of 64 PM2.5 samples, 100% contained at least two NEOs (imidacloprid and acetamiprid). Imidacloprid was detected at the highest levels, ranging from 4.33 to 1.13 × 102 pg m−3. A relative potency factor method that considered different toxicities was used to integrate the four NEO concentrations. The total NEO concentrations in air in the Zhengzhou rural area (mean: 80.86 pg m−3) were higher than those in urban areas. Differences between seasons were not significant (p > 0.05). The highest value for the total average daily dose via inhalation of four NEOs (ADDinh,total), 91.0 pg kg−1 day−1, was found in rural children