This data is based on the monitoring results of the ambient air quality monitoring stations set up by the Environmental Protection Administration of the Executive Yuan. According to national and municipal statistics, this data shows the AQI index value of each station each day by using the piecewise linear equation to calculate the 7 concentration values of the 6 main pollutants, including ozone (O3), fine suspended particles (PM2.5), suspended particles (PM10), carbon monoxide (CO), sulfur dioxide (SO2) and nitrogen dioxide (NO2) in the air every day, and calculating the number of station days and the ratio of AQI>100 days based on the degree of its impact on human health.