兰州市不同径粒大气颗粒物污染特征及气象因子的影响分析

Lanzhou Different Diameter Grain of Atmospheric Particulate Matter pollution Characteristics and the Influence of meteorological factor Analysis

空气污染程度与就诊率、呼吸道发病率及死亡率等有着密切的联系。兰州市在上世纪末曾被喻为卫星上看不到的城市,它的大气污染程度一直以来为人们所关注。利用2013年国家环保部公布的兰州市5个监测点（涵盖了4区1县）大气细粒子PM10及PM2.5的监测数据,针对全年的日均PM2.5与PM10质量浓度并结合了同期的气象因子进行分析研究,结果表明：春冬季为兰州大气中两种颗粒物的污染的高峰期（春季峰值为3月份,PM10及PM2.5质量浓度的月均值为309和103μg·m^-3,超标倍数为1.062与0.436;冬季峰值为11月份,PM10及PM2.5质量浓度的月均值为203和85μg·m^-3,超标倍数为0.353与0.7）,夏秋季为低谷（波谷为9月份,PM10及PM2.5的月均值为96和39μg·m^-3,均低于国家标准）。PM2.5与PM10质量浓度比值均在0.4与0.5之间,呈一定的线性关系,大气污染较轻。当温度在-3-0℃之间时,大气中PM2.5与PM10质量浓度变化较剧烈。露点温度高于-3.15时,使得PM10的质量浓度下降明显;当日均露点温度高于1.85时,PM2.5的质量浓度随着露点温度的增大而降低,说明湿沉降对着两种粒子的清除作用明显。降水对大气中的两种颗粒物均呈现清除作用,但是在降水后PM10质量浓度迅速回升,但PM2.5质量浓度却变化不大。风向偏西时,大气中细颗粒污染物浓度增加。风速的增加对PM2.5有一定的清除作用,但由于兰州市的地貌特征,使得大气中PM10的质量浓度增加。上述结果为兰州市大气污染的监测与治理及大气污染预报提供了重要的依据。

Air pollution has closely related between visiting rate, respiratory morbidity and mortality rates. Lanzhou city has been referred to not be shoot by the satellite at the end of the last century, air pollution in this city has been of concern for people. According to the monitoring data of PM10 and PM2.5 which have been announced by the State Environmental Protection Department of China at 5 monitoring points＇（include four districts and one county） in Lanzhou city in 2013, PM2.5 and PM10 mass concentration of average daily and combined with the meteorological factors during the same period were analyzed and studied. the results showed that： For in the spring and winter at the peak of the two kinds of particles in the atmosphere pollution in lanzhou,（The spring peak in March, PM10 and PM2.5 mass concentration of the monthly mean are 309 μg·m^-3 and 103 μg·m^-3,exceed the standard ratio are 1.062 and 0.436. The winter peak in November, PM10 and PM2.5 mass concentration of the monthly mean are 203 μg·m^-3 and 85 μg·m^-3, exceed the standard ratio are 0.353 and 0.7.）, fall into trough（Trough for September, PM10 and PM2.5 mass concentration of the monthly mean are 96 μg·m^-3 and 39 μg·m^-3,they are lower than the national standard）. PM2.5 and PM10 mass concentration ratio is between 0.4 and 0.5, a certain linear relationship, atmospheric pollution is lighter. When the temperature between 0-3 ℃, PM2.5 and PM10 mass concentration in the atmosphere is more intense. The dew point temperature is higher than-3.15, which makes the mass concentration of PM10 decreased obviously. On that the dew point temperature is higher than 1.85, the mass concentration of PM2.5 decreased with the increase of the dew point temperature. These can illustrate that it＇s obviously for wet deposition to two particle scavenging effect. Precipitation of the two kinds of atmospheric particulate matter are presented scavenging effect, but after precipitation PM10 mass concentration quick recovery, but little change PM2.5 mass concentration. The wind by west, increase the fine particle pollution levels in the atmosphere. Wind speed increase of PM2.5 has clear effect, but it makes the quality of the atmospheric PM10 concentration increased. The above results provide a important reference data for the monitoring and management of air pollution in Lanzhou City and provides strong theoretical basis for air pollution forecast in the future.