Estimation of Fuel Loadings of Domestic Agricultural Crop Residues to Determine the Air Pollutants Emissions

Open burning of agricultural residues is one of the significant sources of air pollution. The quantification of air pollutants emissions by open burning requires the fuel loadings calculated from the biomass and the crop's burning ratio that indicates the mass fraction of crop residues incinerated to the total crop residues. The survey of 1,004 domestic farmers in 2020 found that the burning ratio was 13.6%, and the compost recycling was 73.5%. The burning ratio varied from region and crop. The burning ratio in Gyeonggi-do was the highest at 31.7%, followed by Chungcheongbuk-do at 21.6%, Jeollabuk-do at 19.1%, and Gyeongsangnam-do at 15.5%. The pepper's burning ratio was 33.6%, followed by pear at 27.5%, peanut at 25.6%, and barley at 21.0%. Compared to 2014, the burning ratio decreased significantly. The average burning ratio of ten crops dropped by 71.6%, and particularly that of fruit trees' residue such as pear, apple, peach, and grape decreased by 78.5%. The biomass conversion factors to the annual crop yields provided by Statistics Korea reasonably presented the annual mass of agricultural crop residues. Finally, the fuel loadings at the agricultural open burning for twenty residues were estimated by multiplying the burning ratios by the mass of agricultural crop residues. As of 2019, the fuel loading of apples was the highest at 128,217 ton/yr, and those of pepper and barley were 68,523 ton/yr and 51,661 ton/yr, respectively. Open burning of agricultural crop residues is one of the long-standing treatment ways. However, to reduce the emission of air pollutants, it is most effective to promote recycling, such as compost or livestock feed.