烟台市区降水化学特征及“十三五”期间变化趋势研究

Chemical Characteristics and Changing Trends Precipitation in Yantai during 13th Five-year Plan Period

2016年-2020年烟台市降水pH值在5.81~8.69之间,加权平均值为6.82,pH月均春季偏高夏季偏低,降水电导率与离子总浓度呈显著正相关。降水中Cl^(-)为主要阴离子,Ca^(2+)为主要阳离子。相关性分析表明烟台市区降水pH不与某一种离子单独相关;降水中多数酸性离子与碱性离子呈显著或极显著相关,降水酸性得到比较好的中和。“十三五”期间,烟台市降水酸度稳定,电导率及9种离子浓度均呈显著下降趋势;SO^(2-)_(4)在阴离子中占比逐年下降,NO^(-)_(3)占比逐年上升,体现出大气复合型污染的特征;降水SO^(2-)_(4)与大气SO_(2)、降水NO^(-)_(3)与大气NO_(2)变化趋势一致。

From 2016 to 2020,the pH of precipitation in Yantai is between 5.81 and 8.69,the weighted average is 6.82,the pH is higher in spring and lower in summer,and the conductivity of precipitation is positively correlated with the total ion concentration.In precipitation,Cl^(-)is the main anion and Ca^(2+) is the main cation.The correlation analysis show that the pH of precipitation in Yantai City is not related to a single ion.Most of the acidic ions in precipitation are significantly or extremely significantly related to the basic ions.The acidity of precipitation is well neutralized.During the“13th five-year Plan”period,the acidity of precipitation in Yantai was stable,the electrical conductivity and the concentration of 9 kinds of ions decreased year by year.The proportion of SO^(2-)_(4) in anions decreased year by year,and that of NO^(-)_(3) increased year by year,which showed the characteristics of complex pollution.The variation trend of precipitation SO^(2-)_(4) was consistent with that of atmospheric SO_(2) and precipitation NO^(-)_(3) with that of atmospheric NO2.