2014—2020年拉萨市环境空气质量评价分析

Evaluation and Analysis of Ambient Air Quality in Lhasa from 2014 to 2020

为了解和评估近年来拉萨城市大气污染现状,本文利用2014—2020年拉萨市环境空气质量监测数据,用主成分分析法和Spearman秩相关系数法对拉萨监测站的6类污染物进行评价分析。结果表明:2014—2020年期间拉萨市首要污染物为PM2.5,且与PM10、NO_(2)的浓度存在一定的相关关系;在评价结果中发现,2014—2020年拉萨市的空气污染程度逐年有所减弱,这期间3类污染物(PM10、PM2.5、SO_(2))的浓度变化具有显著下降趋势;对PM10、PM2.5、SO_(2)浓度含量的年际变化进行动态分析,在2014—2020年期间这3类污染物的平均值、最大值以及最小值的秩相关系数均处于显著下降趋势;在这3类污染物(PM10、PM2.5、SO_(2))的年内变化特征中发现,其浓度最高值均出现在每年冬季的12月至次年1月,9月至10月是污染物浓度上升趋势开始的时间节点,而5月至8月是污染物浓度明显下降趋势的时间段,因此,拉萨市3类污染物浓度变化与季节有明显的相关性。

With the rapid development of urbanization in Lhasa,the number of motor vehicles has increased greatly,which makes the air pollution problem more and more serious.Based on the air quality data of Lhasa provided by the weather post-report,the six types of pollutants monitored from 2014 to 2020 were evaluated and analyzed by principal component analysis and Spearman rank correlation coefficient method.The results show that from 2014 to 2020 the primary pollutant in our city is PM2.5,which has a certain correlation with the concentration of PM10 and NO_(2).In the comprehensive evaluation results,it is found that the pollution degree has weakened year by year from 2014 to 2020;From 2014 to 2020,the concentration changes of PM10,PM2.5 and SO_(2) showed a significant downward trend.Then,through the dynamic analysis of the concentration changes of PM10,PM2.5 and SO_(2),it was found that the juvenile correlation coefficients of the average value,maximum value and minimum value of these three pollutants in 2014—2020 were all in a significant downward trend.In the analysis of the annual changes of the three kinds of pollutants with significantly reduced concentrations,it is found that the highest concentrations of the three kinds of pollutants all appear from December to January,and they start to rise in October,while they obviously show a downward trend from May to August.