Spatio-temporal Variation and Influencing Factors of Tropospheric HCHO Column Density in Jinan City from the 11th to the 13th Five-Year plan

Using the OMI tropospheric HCHO column density product, the spatio-temporal distribution characteristics of HCHO column density in Jinan for 2006 — 2020 were studied, as well as its impact factors from the aspects of meteorology, social economy and environmental protection policies. The results demonstrated that tropospheric HCHO column density had a large fluctuation on the temporal scale. A declined trend during the 11th Five-Year Plan period, an increasing trend of fluctuation during the 12th FiveYear Plan period, and a declined trend of fluctuation during the 13th Five-Year Plan period were found. The column density was highest in summer, followed by spring and autumn, and lowest in winter. The highest value appeared in July, August and September;and the lowest value appeared in January, November and December. The column density was lower in the southern mountainous area than that in the main urban area. HCHO had both local emission and surrounding areas. Monthly mean precipitation and temperature were positively correlated with HCHO column density, while barometric pressure was negatively correlated. Social and economic development had a great influence on HCHO column density. The promulgation and implementation of a series of environmental laws and policies had played a positive role in the reduction of HCHO column density.