基于多尺度交叉趋势样本熵的城市空气质量指数分析

为了研究城市的空气质量指数（air quality index，AQI）与各污染物浓度序列之间的一致性，以及相邻城市间污染物的相似程度，提出一种新的多尺度交叉趋势样本熵（multiscale cross trend sample entropy，MCTSE），用于刻画2个具有趋势的序列在不同尺度上的一致性。利用该方法对长沙、株洲和湘潭3个城市春、夏、秋、冬的AQI与PM_2.5、PM₁₀、SO₂、NO₂、CO和O₃ 6种污染物浓度序列展开研究，为寻找影响这些城市空气质量的污染源以及共同治理提供参考。最后为这些城市制定空气污染防治目标提出了可行的治理对策。

ANALYSIS OF URBAN AIR QUALITY INDEX BASED ON MULTISCALE CROSS TREND SAMPLE ENTROPY

In order to study the consistency between air quality index (AQI) and various concentration series of pollutants in a city, as well as the similarities of each pollutant between its neighbor cities, a multi-scale cross-trend sample entropy (MCTSE) was proposed in this paper. The new method could be used to characterize the consistency of two series, and each of which had trend on different scales. It was applied to investigate the consistency between AQI and concentration series of PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃ in four seasons in Changsha, Zhuzhou and Xiangtan. The same method was also used to study the similarities of each pollutant between every two of these three cities. It provided a theoretical basis for finding pollution sources that affected the air quality of these cities and jointly preventing and controlling air pollution. Finally, the aim of air pollution prevention and control was formulated, and the feasible countermeasures were put forward.