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 (10^th and 90^th 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).

一氧化碳是能源富集区域的首要污染物。本研究基于观测得到的一氧化碳与甲醛柱浓度，采用天基质量守恒框架，对中国能源大省山西省的一氧化碳排放量进行量化。相较于部分现有数据集，本研究得到的年化总排放量平均高出7倍，这在一定程度上源于低排放区域能源消费占比的提升，进而造成空间错位。这最终导致二氧化碳（CO₂）排放量净增加7%。一氧化碳的关键影响因子包括大气寿命（一氧化碳与甲醛的10%、90%百分位数对应的时长分别为[1.0, 5.7]天和[0.2, 2.3]小时）与大气输送过程。一氧化碳浓度呈逐年下降趋势，但仅在2至3个排放峰值月份表现显著。在上述峰值月份，跨区域输送作用显著，污染源包括陕西中部与河北西部。一氧化碳与氮氧化物的比值存在显著差异，可用于工业区域（包括水泥、电力、钢铁及焦化行业）的污染源溯源。