安宁市2019-2023年大气降水离子变化特征及来源分析

Ion Variation Characteristics and Source Analysis of Atmospheric Precipitation in Anning City from 2019 to 2023

通过对安宁市2019-2023年降水监测数据进行统计分析,了解安宁市大气降水离子变化特征及规律。分析结果表明:2019—2023年安宁市未出现酸雨,降水pH加权年均值范围为7.09~7.73,整体呈弱碱性;除2023年外,其余4年降水电导率呈下降趋势,降雨质量有所好转;SO_(4)^(2-)、NO_(3)^(-)为主要阴离子,Ca^(2+)、NH_(4)^(+)为主要阳离子,SO_(4)^(2-)/NO_(3)^(-)值呈下降趋势,但趋势不显著,除2021年外,其余4年均为混合型降水;Cl^(-)呈上升趋势,且趋势显著,降水中过量氯的致酸性在逐渐增加,对含氯废气治理需要引起重视。

Through the statistical analysis of precipitation monitoring data from 2019 to 2023 in Anning City,the characteristics and patterns of ion variations in atmospheric precipitation were explored.The analysis results indicated that there were no acid rain occurrences in Anning City during 2019—2023.The weighted annual average pH of precipitation ranged from 7.09 to 7.73,overall exhibiting weak alkalinity.Except for 2023,the electrical conductivity of precipitation showed a declining trend in the other four years,indicating an improvement in rainwater quality.SO_(4)^(2-) and NO_(3)^(-) were the dominant anions,while Ca and NH_(4)^(+) were the main cations.The SO_(4)^(2-)/NO_(3)^(-)ratio demonstrated a decreasing trend,although not significantly.Except for 2021,the precipitation was of a mixed type in the other four years.The trend of Cl^(-) was significantlyupwardwith the acidity caused by gradually increasingexcessive chlorine in precipitation.Attention needs to be paid to the management of chlorine-containing waste gases.