The Gansu Key Laboratory of Arid Climate Change and Reducing Disaster, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
Mountain Environment and Meteorology Key Laboratory of Education Bureau of Sichuan Province, College of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225, China; The Gansu Key Laboratory of Arid Climate Change and Reducing Disaster, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
Sci Total Environ. 2018 Jan 15;612:975-984. doi: 10.1016/j.scitotenv.2017.08.205. Epub 2017 Sep 6.
Sichuan Basin, located in southwest China, has been ranked as the fourth of heavily air polluted regions in China partly due to its deep mountain-basin topography. However, spatial-temporal distribution of air pollution over the basin is still unclear due to the lack of monitoring data and poor knowledge. Since January 2015, six criteria air pollutants began to be monitored in 20 cities across the basin. The measured data enable us to analyze the basin-wide spatial-temporal distribution characteristics of these air pollutants. Results revealed heavy air pollution in the bottom zone, medium in the slope zone, and light pollution in the edge zone of the Basin in terms of the altitudes of air quality monitoring stations across the Basin. The average concentrations of PM and PM were 55.87μg/m and 86.49μg/m in the bottom, 33.76μg/m and 63.33μg/m in the slope, and 19.71μg/m and 35.06μg/m in the edge, respectively. In the bottom and slope of the basin, high PM concentration events occurred most frequently in winter While in summer, ozone became primary pollutant. Among the six air pollutants, concentrations of PM and PM decrease dramatically with increasing altitude which was fitted by a nonlinear relationship between particulate matter (PM) concentrations and altitude. This relationship was validated by extinction coefficient profiles from CALIPSO observations and EV-lidar data, and hence used to reflect vertical distribution of air PM concentrations. It has been found that the thickness of higher PM concentrations is less than 500m in the basin. In the bottom of the basin, PM concentrations exhibited stronger horizontal homogeneities as compared with those in the North China Plain and Yangtze River Delta. However, gaseous pollutants seemed not to show clear relationships between their concentrations and altitudes in the basin. Their horizontal homogeneities were less significant compared to PM.
四川盆地位于中国西南部，由于其深盆山地形，部分地区被列为中国第四大重污染区。然而，由于监测数据的缺乏和知识的不足，该盆地的空气污染时空分布仍不清楚。自 2015 年 1 月以来，盆地 20 个城市开始监测 6 项标准空气污染物。测量数据使我们能够分析这些空气污染物在整个盆地的时空分布特征。结果表明，从整个盆地的空气质量监测站海拔高度来看，盆地底部污染严重，坡度区中度污染，边缘区轻度污染。盆地底部、坡度区和边缘区 PM 和 PM 的平均浓度分别为 55.87μg/m 和 86.49μg/m、33.76μg/m 和 63.33μg/m、19.71μg/m 和 35.06μg/m。在盆地的底部和坡度区，冬季高 PM 浓度事件最频繁，而在夏季，臭氧成为主要污染物。在这 6 种空气污染物中，PM 和 PM 的浓度随着海拔的升高而显著降低，这与颗粒物（PM）浓度与海拔的非线性关系相吻合。这种关系得到了 CALIPSO 观测和 EV-lidar 数据消光系数剖面的验证，并因此被用来反映大气 PM 浓度的垂直分布。结果发现，盆地内更高 PM 浓度的厚度小于 500m。在盆地底部，PM 浓度的水平均匀性比华北平原和长江三角洲更强。然而，与 PM 相比，气态污染物的浓度与海拔之间似乎没有明显的关系。它们的水平均匀性不那么显著。
