Lee, J., Jeong, S.*, Park, H., Hong, J., Kim, J., Frey, M. M., Morino, I., Ohyama, H., Hase, F., Mermigkas, M., Zhou, M., Té, Y., & Roehl, C. M. (2024). Emission characteristics of greenhouse gases and air pollutants in Northern Hemisphere cities: Comprehensive assessment using ground-based Fourier transform spectrometers. Journal of Geophysical Research: Atmospheres, 129(12). https://doi.org/10.1029/2023jd040562

Abstract:

Despite the importance of understanding the urban emission characteristics of greenhouse gases (GHGs) and air pollutants, few studies have conducted integrated assessments across diverse urban environments. Herein, we conducted a comprehensive evaluation of the emission characteristics of GHGs and air pollutants in seven cities in the Northern Hemisphere using ground-based Fourier transform spectrometers. Our analysis primarily focused on emission ratios of excess column-averaged dry-air mole fractions of carbon monoxide (CO) to carbon dioxide (CO2) (∆XCO:∆XCO2) and those of methane (CH4) to CO2 (∆XCH4:∆XCO2). We found that the emission ratios varied significantly across cities. Xianghe (China) and Pasadena (USA), known for severe air pollution, showed the highest emission ratios. Notably, Seoul (South Korea) showed lower ∆XCO:∆XCO2 (3.32 ± 0.10 ppb/ppm) but relatively higher ∆XCH4:∆XCO2 (4.85 ± 0.04 ppb/ppm), which was comparable to the ∆XCH4:∆XCO2 value of Xianghe (5.15 ± 0.10 ppb/ppm), suggesting that targeted CH4 reduction strategies may be required for climate change mitigation in Seoul.