Spatiotemporal variations and potential sources of tropospheric formaldehyde over eastern China based on OMI satellite data

The eastern region is an important economic hinterland and energy region of China; however, the rapid economic development and the decoupling of environmental pressure have resulted in a significant increase in volatile organic compound (VOC) emissions, and the region is facing the air pollution problem of high-concentration formaldehyde accumulation. The Aura/Ozone Monitoring Instrument (OMI) remote sensing satellite can perform long-term and large-scale dynamic monitoring of tropospheric formaldehyde, and its data can reflect the distribution of formaldehyde column concentration in the study area. This article discusses the spatial and temporal characteristics of formaldehyde in eastern China from 2009 to 2018 based on OMI's formaldehyde column concentration data daily products. In addition, based on the Multi-resolution Emission Inventory for China (MEIC), the potential contributions of natural sources (isoprene) and anthropogenic sources (industrial sources, transportation sources, and residential sources) to formaldehyde are analyzed. The results show that the formaldehyde column concentration is higher in eastern China, and the high-value areas are mainly concentrated in regions with close human activities, such as Jing-Jin-Ji (JJJ), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD), and the concentration is predicted to increase slowly in the future. One of the main sources of formaldehyde is isoprene emitted by plants, but the impact of human activities on formaldehyde cannot be ignored. The OMI data can objectively reflect the spatiotemporal distributions and change characteristics of formaldehyde in large areas and effectively characterize the accumulation of atmospheric pollutants; thus, the use of OMI can provide an important theoretical basis and reference value for the improvement of regional ecological environment and atmospheric quality.