S1. Calculation procedure for vanadium emission pertinent to coal combustionThe development of vanadium emission inventories utilized collected raw data set from various resources, which were processed in streamlined procedure as illustrated in the following sections, and the raw data set have been provided in the data spreadsheet (denoted as SS-A\B\C\D\E), uploaded in the public repository (Zhang, 2023).The coal combustion was common in many sectors, such as power plants, industrial productions, residential, and various other processes. Both raw coal and coke reported contained vanadium contents (Lee et al., 2002). Combustion of raw coal usually involves operation of various types of coal-fed boilers (Tian et al., 2010), from which vanadium bearing fly ash went through the downstream flue gas control device and were partially removed, the remaining flue gas was emitted into the atmosphere through the stacks (Tian et al., 2012). Coke was primarily used in coal-fired plants as secondary fuels, or steelmaking processes (Visschedijk et al., 2013), inducing vanadium emission predominantly through air pathway (Moreno et al., 2010).The anthropogenic vanadium emission induced by coal consumption can be attained thorough the following method (Bai et al., 2021):Where E(t) was the total amount of vanadium emission due to coal consumption at year t; A represented the yearly consumption of coal type j (raw coal or coke) in province I; C was the vanadium content in coal type j in province i; R was the vanadium fraction of released gas from combustion process; 𝜑 was the removal efficiency of flue gas vanadium in the treatment system.Supplementary spreadsheet SS-A1 provided the vanadium content in raw coal produced in each province. SS-A2 provided the vanadium fraction of flue gas from four classic coal combustion boilers. SS-A3 provided the vanadium removal efficiency of typical flue gas treatment system.
S1.1 Raw coalMassive amount of raw coal was transported across province from production area to the consumption area, which led to great variability in properties and trace content between produced coal and consumed coal in the same province. The S2 weighted average of V in consumed raw coal was obtained by combining the annual coal flow matrix among 31 China's province (Tian et al., 2011). V content was assumed to be consistent throughout 2015-2019, SS-A4 provided the weighted average vanadium in raw coal consumed at provincial level. SS-A5 provided the yearly consumed volume of raw coal at provincial level. The above datasets were utilized to calculate the vanadium emission inventory for raw coal and present them in Table S1.
S1.2 CokeAll consumed coke in Chinese province was presumably originated from raw coal.Cj was the V content (g/t) in consumed coke at provincial level; Cy was the vanadium content (g/t) in the raw coal for coke production; My (t) was the amount of raw coal involved in coke production; Mj (t) was the total amount of coke production at provincial level; F was the vanadium fraction in released gas from co...