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Wang et al. Carbon Footprints 2024;3:14 https://dx.doi.org/10.20517/cf.2024.19 Page 13 of 19

Figure 7. Spatial distribution characteristics of absolute (A) and relative (B) Uncertainties in proxy data.

HEI-CD model with a 0.1° resolution [Figure 8A], enabling a valid comparison with the EDGAR inventory
[Figure 8B]. To compare the two inventories, the difference is shown in Figure 8C, where red areas indicate
higher emissions in the HEI-CD model and blue areas indicate higher emissions in the EDGAR inventory.

The spatial distribution of the HEI-CD model was broadly similar to that of the EDGAR inventory. Both
inventories exhibited a spatial distribution pattern where emissions were generally higher in the city center
than in the surrounding areas. However, the surrounding areas showed several high-emission point sources.
Both accurately characterized the high-emission characteristics of key cement production facilities.
However, the HEI-CD model slightly underestimated emissions in this area compared to the EDGAR
inventory, likely due to the more comprehensive point source information in the HEI-CD model, resulting
in a lower allocation of emissions to this region.

In the western side of the study area, the HEI-CD model identified two high-emission areas, indicating that
the EDGAR inventory lacked accurate point source data for this region, thus failing to accurately represent
emissions here. Conversely, on the southern side, the EDGAR inventory overestimated emissions. Visual
inspection did not identify potential high-emission sources, suggesting a likely overestimation by EDGAR
in this area. In the area of High-Emission Zone 3, located in the eastern part of the study region, EDGAR
inventory incorrectly represented the location of the power plant, resulting in discrepancies in high-
emission areas. In the city center, the EDGAR inventory also slightly overestimated emissions compared to
the HEI-CD model.

A histogram [Figure 8D] was generated through quantitative statistical analysis of the differences between
the HEI-CD model and the EDGAR inventory. The histogram revealed that the majority of the emission
differences were centered around the median value of -7.04 kt, with the highest count reaching 120. This
suggested that most points exhibited a small negative emission difference, indicating that the emission
intensities were closely aligned in most areas. It also implied that the HEI-CD model generally estimated
slightly lower emissions than the EDGAR inventory.

DISCUSSION
Interpretation of study results
This study successfully developed a high-resolution, city-scale gridded CO emission inventory for
2
Chengdu, providing a detailed spatial distribution of emissions across various sectors. The analysis
identified three primary high-emission areas: the densely populated city center, the industrially active
northwest region, and the energy-intensive eastern area. Together, these regions accounted for over 40% of