Data sets of AQI, CO and NO2 and O3, PM10 and PM2.5, SO2 from 264 city-level monitoring stations in China

China has a vast territory, and different regions have different air quality conditions. The database selects the air quality of 264 major cities in China as the research object. From the Ministry of Ecology and Environment, PRC (http://www.mee.gov.cn/), China's air quality on-line monitoring and analysis platform https://www.aqistudy.cn/historydata/ for the 264 cities in 2018-2021 per hour AQI and CO, NO2 and O3, PM10 and PM2.5, The hourly monitoring concentration data of six pollutant items of SO2 (except for CO which is mg/m3 and the other units are ug/m3) are averaged over the 24 1-hour data every day to obtain the daily pollutant item concentration index and daily air quality index. All seven kinds of daily data sets of 264 cities from 2018 to 2021 were used as data samples for the study.