Chemical characteristics of precipitation in central Liaoning Province, Northeast China

摘要

The chemical characteristics of precipitation were analyzed based on the chemical composition of principal ionic within acid rain (from February 2007 to January 2008) of Liaozhong Meteorological Station (LMS) located in Malong Village in central Liaoning Province of Northeast China, meteorological conditions on the corresponding period ground, and variation of several air pollutants concentration. The results indicated that(1) theprecipitation ofLMSwas acidic; average pH ofall sampleswas 4.76; the frequency of acid rainduring the observation periodwas 70.7%; the frequency was 82.8%in summer and autumn; andthe acidity was stronger inlarger rainfall season; (2) in the chemical composition of precipitation, the primary anions wereSO42-andNO3-; the primary cations were NH4+and Ca2+;theratioof SO42-/ NO3-was 2.9; and theratioof Na+/Cl-was larger than 1;(3)all concentration of anionswas higher in summer and winter, but relatively low in spring and autumn. This showed that the relationship between regional rainfall acidification and pollution was not significant. The correlation between (∑ anionic / ∑ cationic) and pH was not obvious among the measured 9 kinds of main anions and cations, which explained the main 9 kinds of anions and cations in the current acid rain observation could not completely include precipitation ions composition; and (4) rainwater acidity and near floor gaseous pollution concentration were different from each other, and pH and NOx, CO, NO2and O3concentrations showed significant negative correlation, but was not obvious with SO2concentration. However, the pH and alkaline pollutants, such as particulate, was positively correlative.