Informatics Publishing Limited

Xiuguo Zou ¹, Yan Qian ¹, Shuaitang Zhang ¹

Affiliations
1 College of Engineering, Nanjing Agricultural University, Nanjing, Jiangsu, 210031, CN

Abstract

In order to make full use of national monitoring sites data, the variations of mass concentrations of PM_2.5 and other criteria pollutants in Nanjing City were investigated on the basis of data from nine national monitoring sites. These monitoring sites provide 24 hr average data to evaluate the spatiotemporal variations of PM_2.5 mass concentration. The characteristics of the annual, seasonal, monthly and hourly variations of PM_2.5 mass concentrations were analysed. PM_2.5 concentrations were higher in the winter months, yet lower in the summer and whole afternoon time, but became better and better during 2014-2016. Afterwards Pearson correlation coefficients were calculated between PM_2.5 and other criteria pollutants. The correlation coefficients between PM_2.5 and PM10 at 9 monitoring sites were more than or equal to 0.76, and were lower in spring while higher in winter, summer and fall. However, the correlation between PM_2.5 and SO₂, NO₂, CO varied in four seasons with lower correlation in summer and higher correlation in winter, spring and fall. Through calculating hourly correlation coefficients between PM_2.5 and PM10, SO₂, NO₂, the correlation coefficients between PM_2.5 and PM10 were lower in the afternoon, on the contrary, the correlations of PM_2.5 and SO₂, NO₂ were lower in the night-time and morning. The correlation curves of PM_2.5 and O₃ barely changed, which gives us the information that O₃ was weakly correlated with PM_2.5. The investigation of PM_2.5 and other criteria pollutants may provide some implications for the key reasons leading to the regional high PM_2.5 and lay the foundation for further research of PM_2.5 control strategies in Nanjing.

Keywords

Spatiotemporal Variations, Pearson Correlation Coefficient, PM_2.5, Nanjing City.

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