2014年合肥大气颗粒物污染特征及变化规律

Pollution Characteristic and Spatio-temporal Variation of PM_(2.5) and PM_(10) Aerosol over Hefei City in 2014

为了认识PM_(2.5)和PM_(10)污染特征,收集了2014年合肥市10个大气监测站点逐时监测数据,并利用统计分析方法研究了该区域大气颗粒物时空变化规律。结果显示,2014年合肥市PM_(2.5)和PM10年平均浓度分别为(73.3±14.9)和(115±7.41)μg/m3,细颗粒物超标严重,且颗粒物污染整体表现为冬季>春季>秋季>夏季,6月份出现的污染高峰主要源于当地秸秆焚烧。全年表现周六PM_(2.5)和PM_(10)浓度最高(分别为(88.8±77.8)和(136±90.2)μg/m^3,周三浓度最低(分别为(63.0±33.8)和(103±45.2)μg/m^3),但春季表现为工作日高周末低的"周末效应",其他季节则呈现相反的"周末效应"。昼夜间PM_(2.5)和PM10浓度均呈现双峰趋势,机动车排放和夜间餐饮等活动是关键影响因素。空间上,老城区大气颗粒物污染较新城区严重,城市北边地区较南边污染严重。大气颗粒物与4种气态污染物(SO_2,NO_2,CO和O_3)的线性回归分析表明气态污染物对合肥市大气颗粒物尤其PM_(2.5)有显著影响。

Hourly ambient observation data in 2014 from ten air quality monitoring stations of Hefei City were collected to investigate the pollution characteristic and spatial-temporal variation of PM_(2.5) and PM_(10) aerosol.The results indicate annual average concentrations of PM_(2.5) and PM_(10) were(73.3±14.9) μg/m^3 and(115±7.41) μg/m^3,respectively,suggesting more serious pollution by PM_(2.5) .The highest seasonal average concentrations of aerosol were observed in winter with a descending order of winter >autumn>summer >spring.Elevated concentrations of PM_(2.5) and PM_(10) investigated in June were possibly related to the local straw burning.Furthermore,the highest concentrations of atmospheric particle were found in Saturday,and the lowest values were observed in Wednesday with significant weekend effect in spring,but trans-weekend effects during the others.Diurnal variation of PM_(2.5) and PM_(10) was characterized by bimodal distribution,which clearly depended on the traffic and cooking sources.Spatially,PM_(2.5) and PM_(10) aerosol concentrations were generally at high levels in old areas,as well as in northern areas of the city.Single linear regression analyses suggest that atmospheric particle,especially PM_(2.5) aerosol,was significantly impacted by four gaseous contaminants(SO_2,NO_2,SO_2 and O_3) .