2015年春节成都市郊大气PM_1污染特征分析

Pollution characteristics of atmospheric PM_1 in suburban Chengdu City during the 2015 Spring Festival

为研究西南郊区春节期间气象条件和燃放烟花爆竹对大气PM_1的影响,本文于2015年2月1日至28日期间,对大气PM_1进行了膜样品采集,并分析了化学成分.结果表明,采样期间大气PM_1质量浓度的平均值为76.67μg·m^(-3),大气PM_1中无机元素平均占比为19.9%.2月1日至17日期间,大气PM_1中无机元素平均占比为12%,2月18日至28日期间,大气PM_1中无机元素平均占比为28%,说明烟花爆竹的燃放大幅度增加了大气PM_1中的无机元素.2月9日至14日期间的重污染现象表明,高空500 hPa受弱高压脊控制,高空形势稳定,850 hPa的较高温度(8℃)对逆温层的形成和维持有重要作用,且四川盆地无明显变压,均不利于污染物扩散.后向轨迹分析表明,PM_1浓度累积与来自东南和东北低空气团有关.

To investigate the influence of firecrackers and the winter meteorological conditions on PM1,samples of atmospheric PM1 in suburban Chengdu were collected during February 1st to 28th,2015 and their chemical components were analyzed.Results showed that during the whole sampling period,the average mass concentration of the atmospheric PM1 was 76.67μg·m-3,19.9%of which was inorganic elements.It was noted that the inorganic elements accounted for 12%in the period of February 1st—17th,and 28%in the period of February 18th—28th,indicating that the firecrackers contributed to the inorganic elements in the atmospheric PM1.The heavy pollution process in the period of February 9th—14th showed that 500 hPa at high altitude was controlled by the weak high pressure ridges,and the situation at high altitude was stable.The heavy pollution process also showed that the high temperature(8℃)at 850 hPa played an important role in the formation and maintenance of inversion layer,and there was no significant pressure change in the Sichuan Basin,which was not conducive to the diffusion of pollutants.Analysis of the backward trajectory revealed that the accumulation of PM1 at suburban Chengdu city was associated with low air masses from the southeast and northeast.