Abstract The hourly tropospheric NO2 vertical column density values measured by Tropospheric Emissions: Monitoring of Pollution (TEMPO) were used to study the NO2 diurnal variability in 32 urban areas. A recently developed algorithm 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 background component demonstrated a clear diurnal cycle with a maximum in the early morning and a minimum in the late afternoon. The urban component, measured as total NO2 mass in urban plumes, ranged from 50% to 150% of the noon values throughout the day and showed considerable variation across the TEMPO domain. TEMPO data also demonstrated a significant weekend effect: On Sundays, urban plume NO2 levels typically decreased by 30%–60% compared to workday values throughout the day. On Saturdays, the reduction was less pronounced.
Observations from the Little Bunker
Last updated: November 30, 2025 04:25 AM
Atmospheric CO₂
426.8 ppm
+18.1
ppm/year
Atmospheric CH₄
1927.61 ppb
+2.73
ppb/year
Global Temperature
+1.48 °C
Peak: +1.73°C
World Population
8.1 billion
+67
million/year