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Carbon Monoxide (CO)
Most of the change in CO emissions is driven by reductions in NEI onroad mobile sources in 2025 relative to the base, as seen in this plot showing the difference between January monthly total CO emissions from onroad mobile sources. O&G sources drive CO increases in the Denver-Julesburg Basin, NW New Mexico, and NE Utah.
Nitrogen Oxides (NOx)
The NOx emissions changes are driven by similar sources as carbon monoxide. Large NEI onroad mobile source reductions in 2025 relative to the base can be seen in a plot of January total onroad mobile source NOx changes between 2025 and 2011.
The 3SAQS surveyed O&G sources drive regional NOX increases in the Denver-Julesburg Basin, NW New Mexico, and NE Utah
. The 3SAQS surveyed O&G inventory also projects NOx emissions decreases in the Piceance Basin in northwest Colorado, Uintah County in northeast Utah, and in the North San Juan basin in northwest New Mexico.
Total Organic Gases (TOG)
Basin by basin increases and decreases in future year TOG emissions are driven by sources in the surveyed 3SAQS O&G inventory
. Decreases in future year TOG emissions are primarily the result of reductions in TOG from onroad
Projected increases in livestock NH3
and seasonal changes in onroad mobile
emissions drive the changes in NH3 in the 4-km domain.
Sulfur Dioxide (SO2)
Elevated point sectors like EGU and non-EGU point are the largest sources of SO2 emissions. As these tile plots show low level emissions only, they don't reflect the future year emission changes due to the elevated source sectors. The reductions in low-level SO2 are due primarily to the nonpoint sector
. Reductions in residual oil combustion drive the SO2 decreases seen in Utah. The increase in SO2 emissions northwest of Phoenix, Arizona is from cement manufacturing in Yavapai county.
Fine Particulate Matter (PM2.5)
Changes in PM emissions in the west are driven by increases in the fugitive dust sector
. While all sources of fugitive dust are projected to increase, unpaved road dust sources are projected to experience the largest increase across much of the west, leading to the PM2.5 emissions increases seen in New Mexico and Wyoming. The fugitive dust increases are offset by decreases in the onroad mobile sector
, as seen in the widespread PM2.5 emissions reductions in Colorado.