Space-based inversion reveals underestimated carbon monoxide emissions over Shanxi

Carbon monoxide is a primary pollutant in energy-rich regions. Here we use a space-based mass-conserving framework based on observed carbon monoxide and formaldehyde columns to quantify carbon monoxide emissions over the energy-driven province of Shanxi, China. Annualized total emissions are seven times higher on average compared with some existing datasets, partly due to the fractional increase in low-emitting area’s energy consumption, resulting in a spatial mis-alignment. This induces a net 7% increase in CO2 emissions. Substantial forcings include atmospheric lifetime (10th and 90th percentile of carbon monoxide and formaldehyde are [1.0, 5.7] days and [0.2, 2.3] hours) and transport. Carbon monoxide decreased year-by-year, although only obvious at the two/three peak emission months. Cross-border transport is important during the same months, including sources from central Shaanxi and western Hebei. Carbon monoxide to nitrogen oxides ratios show obvious differences and give source attribution over industrial areas (including cement, power, iron/steel, and coke). Carbon monoxide emissions in Shanxi, China are up to seven times greater than existing datasets predict, especially over low emission areas, according to an inversion study using satellite data.