西北干旱区PM10浓度特征及其与水平能见度的关系

摘要

By using the API, PM10 data from meteorological departments and the visibility, humidity data from environmental departments, the spatial and temporal distribution characteristics of 19, 5, 13 PM monitoring stations in Xinjiang, Gansu, Inner Mongolia in arid northwest China in 2011─2013 is analyzed respectively. The relationship between PM10 concentration and horizontal visibility(including all weather and clear sky, dry visibility and dry extinction coefficient)) in Xinjiang is researched, to realize PM10 concentration situation in arid northwest China and to provide a scientific basis to control PM10 pollution. The results show that: (1)From 2011─2013, there are obvious differences in PM10 concentration over the whole arid northwest China, and the PM10 concentration in Xinjiang is significantly higher than in Gansu, Inner Mongolia. The PM10 concentration of the most cities in Xinjiang and Gansu has already exceeded the national quality standards grade 2. In terms of the seasonal distribution, the PM10 concentration in spring and winter is relatively higher than in autumn over the whole arid northwest China, and in summer the lowest. (2)From 2011─2013, the PM10 concentration monthly variability fluctuations of the most cities in arid northwest China are large, and the fluctuation curves are “M”, “U”, “N” and “n”, respectively. (3) PM10 concentration is negatively correlated with the level of horizontal visibility. To reduce the analytical deviation, PM10data is grouped by 100μg·m-3 step, and the relationship between PM10 concentration anomaly and horizontal visibility anomaly is analyzed. Visibility anomaly shows positive value if PM10 concentration is negative anomaly, and the horizontal visibility is higher than mean value under the correspondingly appropriate weather conditions. Visibility anomaly shows negative value if PM10 concentration is positive anomaly, and the horizontal visibility is lower than mean value under the correspondingly appropriate weather conditions.%利用环保部门的API、PM10数据和气象部门的能见度、相对湿度等相关数据，分析了2011─2013年西北干旱区（包括新疆、甘肃、内蒙古PM监测站点分别19个、5个、13个）PM10浓度的空间分布特征和时间变化特征，并以新疆为例，研究了其PM10浓度特征及其与水平能见度（包括全部天气条件和晴空条件，以及干能见度、干消光系数）的关系，以期了解西北干旱区的PM10浓度状况，为有效控制PM10污染提供科学依据。结果表明，（1）2011─2013年，整个西北干旱区的PM10浓度存在明显的区域差异，新疆的PM10浓度明显高于甘肃、内蒙古，且新疆和甘肃大部分城市的PM10浓度已超过国家二级质量标准。就季节分布而言，整个西北干旱区冬春季PM10浓度相对较高，秋季次之，夏季最低。（2）2011─2013年，西北干旱区绝大多数城市的 PM10浓度月变化波动都比较大，波动曲线基本呈现出“M”型、“U”型、“N”型和“n”型4种。（3）PM10浓度与水平能见度呈负相关关系。为了降低分析误差，我们将PM10数值以100µg·m-3为步长进行了分组，分析了 PM10浓度距平与水平能见度的关系，得出当 PM10浓度为负距平时，能见度距平多为正值，且对应的水平能见度比相应气象条件下的平均值高，而当PM10浓度为正距平时，能见度距平多为负值，且对应的水平能见度比相应气象条件下的平均值低。