Analysis of Atmospheric Pollution Status over Nanjing Based on Multi-Source Detection

Abstract

Nanjing, as one of the core cities in the Yangtze River Delta, has developed industries and serious air pollution. In order to further study the pollution status in Nanjing, MODIS and CALIPSO's aerosol products were used to analyze the aerosol characteristics of Nanjing from 2011 to 2019. Then, four kinds of common reactive gases (SO2, NO, NO2 and O3) in the atmosphere of Nanjing in winter were analyzed based on the data of ground-based reactive gas analyzer. The results shows that: (1) The AOD over Nanjing showed a downward trend in the whole nine years, and the AOD could reach 0.7 in winter. The pollution degree was the highest in the four seasons. The aerosol was mainly composed of coarse particles and absorbent particles in winter. (2) The near surface atmosphere (within 2 km) of Nanjing was dominated by large particles and irregular particles. Mainly, the proportion of fine particles and regular particles gradually increased within 2-6 km, and the volume of particles changed little within 2-6 km. (3) Among the four common reactive gases in winter, the φ(NO) in the atmosphere was the most significant, and the maximum value was 160×10-9, and the change trend of NO2 and O3 was opposite. Due to the emission limitation and the promotion of desulfurization measures, and the influence of photochemical reaction, the φ(SO2) was the lowest, only about 3×10-9. Combined with OMI data, the φ(NOx) over Nanjing remained at a low level in early 2020 due to the shutdown of factories because of COVID-19. Studies have shown that the particulate pollution in Nanjing has improved in recent years, but it is still necessary to pay attention to the emission of coarse particles, and it is necessary to strictly control the emission of gaseous pollutants from factories, especially NOx. © 2021, Editorial Board, Research of Environmental Sciences. All right reserved.