Variation trends and principal component analysis of nitrogen oxide emissions from motor vehicles in Wuhan City from 2012 to 2017

Daoru Liu; Qinli Deng; Zhigang Ren; Zeng Zhou; Zhe Song; Jiahui Huang; Ruibo Hu

doi:10.1016/j.scitotenv.2019.134987

Variation trends and principal component analysis of nitrogen oxide emissions from motor vehicles in Wuhan City from 2012 to 2017

Sci Total Environ. 2020 Feb 20:704:134987. doi: 10.1016/j.scitotenv.2019.134987. Epub 2019 Dec 5.

Authors

Daoru Liu¹, Qinli Deng², Zhigang Ren³, Zeng Zhou⁴, Zhe Song¹, Jiahui Huang⁵, Ruibo Hu¹

Affiliations

¹ School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China.
² School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China. Electronic address: deng4213@whut.edu.cn.
³ School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China. Electronic address: renzg@whut.edu.cn.
⁴ School of Urban Planning, Wuhan University, Wuhan 430070, China. Electronic address: haomaoz@whu.edu.cn.
⁵ School of Civil Engineering, Technical University of Denmark, Copenhagen 2800 Kgs, Denmark.

PMID: 31838298
DOI: 10.1016/j.scitotenv.2019.134987

Abstract

In addition to fine particulate matter and oxysulfides, nitrogen oxides (NO_x) emitted by motor vehicles are among the most important pollutants affecting air quality and public health in those urban areas where centralized heating and chemical industry absent. We utilized correlation analysis (pearson correlation coefficient and spearman correlation coefficient) and principal component analysis (PCA) to identify the variation trends and main causes of NO_x emissions from motor vehicles in Wuhan City. We considered the total number of motor vehicles (TN), ratios of motor vehicles of different emission standards (RE), rations of labeled motor vehicles (RL), and rations of motor vehicles' fuel types (RF). The results show that: 1) with an increase in the total amount of motor vehicles, the NO_x emissions of motor vehicles have been decreasing since 2015; 2) three sub-categories (the ratio of the State III emission standard, the ration of yellow label diesel vehicles, and the ration of diesel vehicles) were recognized as key indexes of PE, PL and PF, respectively, in the PCA; 3) a new parameter, the ES_index is proposed as an index to represent the variation trend of the NO_x emissions of motor vehicles in Wuhan City.

Keywords: Correlation; Emission standards; Public health; Sub-factor.