Anion Characteristics of Atmospheric Precipitation and Relevant Research in the 13th Five-Year Plan Period of Tai'an

The variation trend and anionic characteristics of atmospheric precipitation in Tai'an city were studied based on the pH,electrical conductivity,and the concentration of the main anion (SO₄^2-,NO₃^-,Cl^-,F^-) from two precipitation monitoring points in the 13th Five-Year Plan period of Tai'an.In addition,the anionic component characteristics and pollution types of atmospheric precipitation in Tai'an city were analyzed in detail.The results showed that there was no acid rain in Tai'an during the 13th Five-Year Plan,because the pH of atmospheric precipitation ranged from 5.95 to 6.29.The weighted average of precipitation was 2844.4mm,the conductivity range was 21.8～187μs/cm,and the anionic concentration of atmospheric precipitation in Tai'an city was SO₄^2->Cl^->NO₃^->F^-accounting for 63.4%,18.6%,16.5%,and 1.5%sequentially.In 2016 and 2020,the concentration of chloride ion in atmospheric precipitation in Tai'an city was higher than that of nitrate ion,which was different from that in inland cities.It indicated that the local salt mines and salt chemical enterprises were responsible for Cl^-in precipitation.The value of SO₄^2-/NO₃^-in precipitation（1.7 to 6.9） illustrated that the precipitation pollution type in Tai'an city was coal burning and mixed pollution.