Analysis of the tropospheric column nitrogen dioxide over China based on satellite observations during 2008–2017

Özet

This study presents an analysis of the atmospheric column nitrogen dioxide ($NO_2$) over China during 2008–2017. Measurements of $NO_2$ columns obtained from the Ozone Monitoring Instrument (OMI) are used to investigate the temporal and spatial dynamics of $NO_2$. Temporal and spatial distributions of $NO_2$obtained from OMI over China from 2008 to 2017 are presented, and annual changes and trends in the seasonal cycle are shown. The annual mean $NO_2$ columns are found to decrease 13% from 2008 to 2017. $NO_2$ shows significant cyclical seasonal characteristics over China, with maximum values in winter and minimum in summer. In addition, the spatial distribution is unbalanced, the Beijing-Tianjin-Hebei (Jing-Jin-Ji) region, the Yangtze River Delta region and the Pearl River Delta region are found to be highly polluted areas, the NO2 columns in these regions have been declining by 17.6%, 24.5% and 16.7% during 2008–2017 respectively. Yearly variations in the $NO_2$ columns over the four major economic plates are prominent, and there is a maximum in the eastern region and a minimum in the western region during the past decade, these four regions show a downward trend in recent years. Three areas and six groups are important pollution regions, and the $NO_2$ columns over these regions also show decrease trend.