Study on ozone precursors in Beijing based on OLI and TROPOMI satellite data
Formaldehyde(HCHO)and nitrogen dioxide(NO2)are important precursors to ozone.HCHO to NO2 ratio(FNR)indicates the sensitivity of ozone production,serving as a primary reference for ozone pollution control.This study enhances the spatial resolution of TROPOMI HCHO and NO2 columns by oversampling algorithms,and reduces the uncertainty of TROPOMI data.It reveals the spatial distribution characteristics of HCHO and NO2 in Beijing during the summer of 2021.Based on FNR,the study diagnoses the sensitivity of ozone production in the Beijing areas.The study utilizes Landsat 8OLI data to calculate environmental indices and the proportion of impervious surfaces in the Beijing areas,and analyses their relationships with HCHO,NO2,and FNR.This Study aims to reveal the relationship between the degree of urbanization and the emissions of O3,VOCs,and NOx in Beijing.It finds that high NO2 columns are mainly distributed in the center of Beijing urban areas,with significantly reduced NO2 columns in non-urban areas.The mean NO2 columns increases with the proportion of impervious surfaces,but their standard deviation decreases,indicating that as urbanization in the urban areas of Beijing intensifies,the differences in NO2 emissions within urban areas diminish.The HCHO columns in urban Beijing are generally higher than those in non-urban areas,but the contribution of isoprene emissions from vegetation somewhat mitigates the disparity in VOCs emissions caused by the urbanization degree differences.Ozone in the urban area of Beijing and eastern Langfang area is controlled by VOCs,while ozone in the northern suburbs of Beijing is primarily controlled by NOx.The FNR mean decreases with an increase in the proportion of impervious surfaces,indicating that as urbanization in the Beijing area advances,the sensitivity of ozone production gradually shifts to a VOCs-controlled mechanism.
NETL
NSTL
万方数据
