Research on Impacting Factors of Air Quality in the Central Urban Area of Hanzhong City based on Principal Component Analysis(PCA)
According to the data of ambient air and meteorology in the central urban area of Hanzhong City in 2022,the main and important factors of air quality were studied base on Principal Component Analysis(PCA),and the relationships between meteorological indicators and various pollutant concentrations were compared and analyzed.The results showed that the three principal components were extracted by PCA,which reached 79.388%of cumulative variance contribution.This method achieved the desired effect.The first principal component accounted for 51.745%of the variance and mainly including PM2.5,CO,NO2 and PM10,which indicated that PM2.5,CO,NO2 and PM10 were the main factors of air quality.The four indicators were highly positively correlated,the highest correlation coefficient was PM2.5-CO(0.905)and the lowest was PM10-CO(0.751).These results suggested that it was the effective way to improve the air quality by intensively controlling CO,NOx and PM emission of industrial source and mobile source.The second principal component and third principal component accounted for 27.643%of the variance and mainly including wind direction,O3,wind scale and temperature,these indicators were important factor of air quality.The temperature had an obviously impact on the pollutant concentrations,which was significantly positively correlated with O3 and had a negative correlation with other pollutants.The order of influence was CO>O3>NO2>NO2>PM2.5>PM10>SO2.When the temperature was at 5~7℃,the concentrations of PM2.5,PM10,NO2,and CO were relatively higher.In the northeast winds,the average concentrations of PM2.5,PM10 and CO were higher,but O3 was lower,the opposite characteristics exist in the southwest winds.The rising wind scale could help to reduce the concentration of pollutants,but the first and second wind may increase the concentration of O3.
principal component analysis(PCA)air qualitymeteorological factorHanzhong City