Background, urban, and industrial NO2 estimated from TEMPO satellite observations

The hourly tropospheric NO₂ vertical column density (VCD) values measured by TEMPO were used to study the NO₂ diurnal andseasonal variability in 34 urban areas over North America and the Caribbean during the period from August 2023 to October 2024. A recently developed algorithm (Fioletov et al., 2024) isolated three components in tropospheric NO₂ data: background NO₂, NO₂ from urban emissions, and from industrial point sources, and then each of these components was analyzed separately. The method is based on fitting satellite data by a statistical model with empirical plume dispersion functions driven by a meteorological reanalysis. Population density and surface elevation data as well as coordinates of major industrial sources were used in the analysis. The background component demonstrated a clear diurnal cycle with a maximum in the early morning and the minimum in the late afternoon. The urban and industrial components, expressed as total NO₂ mass in urban and industrial plumes, did not show any obvious diurnal cycle in most areas. Only the Los Angeles and Mexico City urban components demonstrated a clear cycle with a maximum in the late morning and a minimum in the late afternoon. Differences between workday and weekend NO₂ levels were also studied. Urban plume NO₂ values on Sundays were typically 30%–60% less than workday plume values throughout the day.  The exception was Havana, where the difference between working day and Sunday values ​​was only 15%.

 

Fioletov, V., McLinden, C. A., Griffin, D., Zhao, X., and Eskes, H.: Global seasonal urban, industrial, and background NO₂ estimated from TROPOMI satellite observations, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-1991, 2024.