贵阳市白云区大气PM_(10)和PM_(2.5)污染特征

Pollution characteristics of PM_(10) and PM_(2.5) in Baiyun District of Guiyang

使用β射线法在线监测仪连续监测了贵阳市白云区PM_(10)和PM_(2.5)浓度,分析了2014年6月1日—12月31日7个月内PM_(10)、PM_(2.5)的浓度水平、时变规律和PM_(2.5)/PM_(10)的变化情况。结果表明,监测时段内PM_(10)和PM_(2.5)的日均浓度平均值分别为76.8μg/m^3和40.0μg/m^3,均达到国家二级标准;浓度超标的天数占总观测天数的5.1%和9.3%,属污染轻微的地区。PM_(2.5)/PM_(10)在25.3%~78.8%之间周期性波动,平均值为52.1%。PM_(10)和PM_(2.5)的浓度变化具有很好的正相关性(r=0.919 8,p<0.000 1);日均值在7个月中呈现明显的周期性变化,各月相对稳定,12月的PM_(10)和PM_(2.5)浓度最高且变化最为剧烈,6月最为平缓。PM_(10)和PM_(2.5)浓度小时变化总体上呈双峰型分布,最高值出现在出现在09:00—10:00和19:00—21:00前后,最低值出现在14:00—17:00之间。

Concentrations of PM_（10） and PM_（2.5）were continuously monitored at an environmental monitoring station in the Baiyun District of Guiyang using an automatic on-line beta-ray absorption method particulate monitor. The concentration level,the temporal variation characteristics of PM_（10） and PM_（2.5）,and the variation in PM_（2.5）/ PM_（10） were analyzed for a seven-month period spanning from June 1 to December 31,2014. The average daily concentrations of PM_（10） and PM_（2.5）during the seven months were 76. 8 μg / m^3 and 40. 0 μg / m^3,respectively,which reached the respective national secondary standards for these particulates. The percentage of days exceeding the national secondary air quality standard were 5. 1% and 9. 3% for PM_（10） and PM_（2.5）,respectively. Particulate pollution is slight in the Baiyun District of Guiyang. PM_（2.5）/ PM_（10） ranged from 25. 3% to 78. 8%,with an average of 52. 1%. The concentrations of PM_（10） and PM_（2.5）were positively correlated（ r = 0. 919 8,p〈 0. 000 1）.The daily average concentrations of PM_（10） and PM_（2.5）showed obvious periodic variations,which were relatively stable. The average concentrations in December were highest and most varied,while those in June were low. The diurnal variations of PM_（10） and PM_（2.5）concentrations showed a bimodal distribution. The maximum values appeared at about 09： 00 to 10： 00 and 19： 00 to 21： 00 and the minimum value appeared between 14： 00 and 17： 00.