County-level and monthly resolution multi-pollutant emission inventory for residential solid fuel burning in Fenwei Plain, China

Abstract

The Fenwei Plain (FWP) in central China is the fourth largest plain nationwide. This region has experienced severe air pollution during the past decades, largely due to residential solid fuel burning. A regional-scale emission inventory covering multi-pollutants was currently unavailable for this area due to the lack of localized emission factors (EFs) from various sources. In this study, localized EFs derived from previous in situ measurements and detailed county-level activity data were used to develop an emission inventory of particulate and gaseous pollutants for the source sector of five residential solid fuels in the FWP in 2020. Emissions of particulate matter with an aerodynamic diameter of ≤2.5 µm (PM_2.5), organic carbon (OC), elemental carbon (EC), ions, polycyclic aromatic hydrocarbons (PAHs), carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO₂), and volatile organic compounds (VOCs) were estimated to be 230-290, 89-160, 20-29, 31-54, 0.93-22, 2100-3600, 64-87, 9.3-12, and 45-92 Gg/yr, respectively. The county-level distribution characteristics differed between pollutant species due to their different EFs and consumption patterns of solid fuels. Shouyang County emitted most for all pollutants (2.66%–4.91% of the region total) except PM_2.5 and SO₂, for which Xiangfen and Hongtong County emitted the most (2.64% and 2.90%), respectively. Emissions were higher in cold (SO₂ during November to January, other pollutants during November to February) than warm months. Uncertainties in this newly developed emission inventory were estimated to be 25.2%–69.8%, much lower than those of existing ones, demonstrating the reliability of this inventory. Gini coefficients indicated that EC, PAHs, NOx, and VOC emissions exhibited evident regional disparities, e.g., Yuncheng and Jinzhong had high pollution levels despite low economic output. Future emission control policies should first focus on developing regions with high pollution in FWP.