aUncertainties in the mass balance approach and Hestia county-level fossil fuel CO2 flux are ± 50% and (-15%, +20% at 95% C.I.), respectively.
bSummertime mass balance flight experiments that were not included in the analysis in Figure 4 to avoid the potential contribution from biogenic CO2 during the growing season.
cIt was not possible to obtain the SSLF contribution from this INFLUX flight experiment, as the landfill plume was well-mixed with the city plume most likely due to the combined effect of relatively slower winds (2.9 m s-1, 232°) and considerable downwind distance of the horizontal transects from the landfill (∼40 km). Hence this INFLUX flight is used in Figure 4 but not included in the analysis in Table 2.