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To overcome the problems of Air Quality Index in describing regional short-term air quality status and changing trend, based on the daily average concentrations of six air pollutants affecting regional air quality in Zhengzhou from 2015 to 2018, this paper analyzes their correlation characteristics and defines an air quality composite index instead of the original index by using factor analysis method, which not only extracts all the information of each Individual Air Quality Index, but also eliminates the correlation among them. At last, it analyzes the difference between the two indices in describing regional short-term air quality status and changing trend.   Key words: Air quality index (AQI), individual air quality index (IAQI), correlation coefficient, partial correlation coefficient, information extraction, factor analysis.

An air quality composite index based on pollutant concentration factor analysis