Long term trends of ozone and its precursors in Seoul obtained from satellite and surface monitoring data

Abstract:

Ozone (O₃) in the urban atmosphere can accumulate from photochemical processes with nitrogen oxides (NO_x), carbon monoxide (CO), and volatile organic compounds (VOCs) which are mainly emitted from anthropogenic activities such as fossil fuel combustions and the use of solvents. Excessive O₃ near the surface has detrimental impacts on the public health of human and ecosystem. In cities, mobile sources emit significant portion of ozone precursors. In Seoul, South Korea, gasoline and diesel are almost equally consumed for on-road/non-road transportation. Because of a high NO_x emission factor of diesel combustion, the diesel passenger vehicles substationally contribute to the total NO_x emissions in Seoul, in which persistently high NO₂ concentrations have been detected from space and ground-based observations. The Korean Ministry of Environment and Seoul Metropolitan Government have implemented the several control measures of the NO_x emissions from vehicles. In this study, we investigated the trends of NO₂, CO, and O₃ in Seoul, using satellite and in-situ observational data from 2005 to 2020. We will present the changes in O₃ and its precursor concentrations in Seoul that have been affected by the environmental policies and recent COVID-19.