Inorganic Chemical Characteristics of PM 2.5 During Pollution Events in Jinan, China

A one-year observation campaign from December 2020 to December 2021 was carried out in Jinan, a city that previously suffered from severe fine particulate matter (PM 2.5 ) pollution. The meteorological parameters and ambient concentrations of the air pollutants were recorded, and PM 2.5 samples were collected during the campaign. The inorganic chemical compositions of the PM 2.5 samples were measured, identifying 8 water-soluble ions (WSIs) and 15 trace metals. Pollution events, including 7 dust events (DEs) and 19 secondary inorganic events (SIEs), were identified and classified. The inorganic chemical compositions of the pollution events were characterized, summarized, and concluded. The low ratio of WSIs to PM 2.5 , high concentrations of Ca 2+ and Mg 2+ , and significant increases in trace metals were the dominant characteristics of PM 2.5 during DEs. The high concentrations of SO 4 2− , NO 3 − , and NH 4 + ; the high ratio of secondary ions to WSIs; and the high ratio of WSIs to PM 2.5 were the dominant characteristics of PM 2.5 during SIEs. Even though, recently, the PM 2.5 pollution in Jinan has not been as severe as pollution from a dozen years ago, it still exists, just at lower frequencies and pollution levels. This investigation provides the characteristics of PM 2.5 pollution under dramatically improved conditions and various ideas for the management and control of PM 2.5 pollution.