Co-benefit potential of urban CO2 and air quality monitoring: A study on the first mobile campaign and building monitoring experiments in Seoul during the winter

Abstract

For the first time, mobile campaign and building monitoring experiments were conducted in downtown Seoul, Korea during the 2018/2019 winter period to assess the possibility of the co-benefit of CO2 emission reduction and air quality improvement. Given that CO2 and air pollutants in cities both originate from fossil fuel combustion, monitoring urban CO2 concentrations using a mobile vehicle and from the top of tall buildings can be a potentially effective approach for diagnosing the air quality. The local enhancement values (Delta species) related to urban emission sources were estimated by eliminating baseline concentrations. The results obtained showed high correlation coefficients between Delta CO2 and Delta air pollutants (i.e., 0.753, 0.505, and 0.525 for Delta CO, Delta NOX, and Delta NO2), confirming the applicability of CO2 as an indicator of air pollutant sources in downtown Seoul. The evaluation of the air quality in the study area using air pollutant ratios, including the ratios of CO and NOX/NO2, relative to CO2 showed that the ratios of Delta CO, Delta NOX, and Delta NO2 relative to Delta CO2 were 5.76, 1.89, and 0.21 ppb ppm(-1). The estimated Delta NO2/Delta NOX ratio (11%) and a comparison of the Delta NOX/Delta CO2 ratios obtained with those reported for other cities in different countries suggested the possibility of a relationship between the current air quality in downtown Seoul and the use of diesel vehicles. Results suggest that the development of municipal policies aimed at mitigating climate change should consider the co-benefit of air quality improvement so as to ensure the effective reduction of CO2 and air pollutant emissions.