衡阳市PM_(2.5)质量浓度时空分布特征及影响因素分析

Spatial and Temporal Distribution Characteristics and Influencing Factors of PM_(2.5)Mass Concentration in Hengyang City

基于PM_(2.5)与其他五种大气污染物浓度数据以及气象资料,选用普通克里金插值与Spearman相关性分析方法,研究了衡阳市PM_(2.5)质量浓度的时空分布特征及其影响因素。结果表明:1)PM_(2.5)质量浓度年均值总体呈下降趋势,季均值具有冬高夏低的特征,月均值变化趋近于“U”型,PM_(2.5)质量浓度小时变化在春冬两季均呈“W”型,夏季为“双峰双谷型”,秋季为“单峰单谷型”。2)PM_(2.5)质量浓度季均值空间分布表现出季节性差异,高值区多集中于衡阳市主城区、衡阳县、衡东县北部、祁东县西北部等地。3)在春、秋、冬三季中,PM_(2.5)与气温、日照时数呈正相关,与相对湿度、风速、降水量呈负相关,但在夏季仅有风速与PM_(2.5)质量浓度具有负相关关系;PM 10、SO_(2)、NO_(2)、CO等污染物与PM_(2.5)在四个季节中均呈正相关,O_(3)与PM_(2.5)除在冬季无相关性外,在其他季节二者之间也具有正相关性。

Based on the concentration data of PM_(2.5)and other five atmospheric pollutants and meteorological data,the spatial and temporal distribution characteristics and influencing factors of PM_(2.5)mass concentration in Hengyang City were studied by Kriging interpolation and Spearman correlation analysis.The results showed that:(1)the annual mean value of PM_(2.5)mass concentration showed a downward trend,the seasonal mean value was high in winter and low in summer,and the variation of monthly mean value tended to be“U”shaped.The hourly variation of PM_(2.5)mass concentration showed a“W”shaped pattern in spring and winter,with“double peak and double valley type”in summer and“single peak and single valley type”in autumn.(2)The seasonal mean spatial distribution of PM_(2.5)mass concentration showed seasonal differences.The high value area was mainly concentrated in Hengyang City,Hengyang County,the north of Hengdong County,the northwest of Qidong County and other places.(3)In spring,autumn and winter,PM_(2.5)was positively correlated with temperature and sunshine duration,and negatively correlated with relative humidity,wind speed and precipitation.However,only wind speed has a negative correlation with PM_(2.5)concentration in summer.PM 10,SO_(2),NO_(2),CO and other pollutants are positively correlated with PM_(2.5)in the four seasons,and O_(3)and PM_(2.5)are positively correlated in other seasons except in winter.