pm2.5数据 可以作为大数据的原始数据(PM2.5 data can be used as the original data of large data)

多重分形去趋势交叉相关性分析，分析时间序列，如股市变动价格，PM2.5数据，外币汇率等(Multifractal detrending cross correlation analysis and analysis of time series, such as stock market variable price, PM2.5 data, foreign currency exchange rate, etc.)

AQI是空气质量指数，根据SO2、NO2、CO、O3、PM10、PM2.5六种污染物浓度计算AQI值，判断空气质量的好坏