Monitoring of Air Pollution by Remote Sensing in Lanzhou City from 2010 to 2019

Based on satellite remote sensing data acquired by the ozone monitoring instrument (OMI), this study used pixel space analysis, a coefficient of variation, stability analysis, and an atmospheric transmission model to determine the concentration of tropospheric ozone (O-3), NO2, HCHO, and SO2 columns in Lanzhou from 2010 to 2019. A series of analyses were carried out on the temporal and spatial distribution of concentration, influencing factors and atmospheric transmission path. The results show that the air pollutants in this area present multi-dimensional characteristics and have a complex spatial distribution. In terms of inter-annual changes, in addition to the increase in the concentration of the HCHO column, the ozone, NO2, and SO2 column concentrations have all decreased over time. In terms of monthly average changes, these four pollutants reached their maximum values in April, December, June, and January, respectively. These four types of pollution had a strong spatial correlation, among which HCHO and SO2 had a significant positive correlation, with a correlation coefficient of 0.76. Many factors affect the atmospheric pollutant in Lanzhou. Among them, pollutants are closely related to urbanization and to the activities of coal-burning industries. Moreover, temperature, precipitation, and sunshine also have certain effects on air quality. The proliferation of pollutants in Gansu Province was one of the sources of pollutants in Lanzhou, while long-distance transportation in the atmosphere from outside the province (Qinghai, Sichuan, and Shaanxi) also exacerbated the pollution in Lanzhou.