A laboratory study of agricultural crop residue combustion in China: Emission factors and emission inventory

The burning of agricultural crop residue represents a major source of trace gases (CO, CO2, NO, NO2, and NOx) and particulate matter on a regional and global scale. This study investigates the gaseous and particulate emissions from the burning of rice, wheat and corn straws, which are three major agricultural crop residues in China, using a self-built burning stove and an aerosol chamber. Emission factors of CO2, CO, NO, NO2 and NOx were measured to be 791.3, 64.2, 1.02, 0.79 and 1.81 g kg−1 for rice straw, 1557.9, 141.2, 0.79, 0.32 and 1.12 g kg−1 for wheat straw, and 1261.5, 114.7, 0.85, 0.43 and 1.28 g kg−1 for corn straw, respectively. The corresponding emission factors of particle number are 1.8 × 1013, 1.0 × 1013, and 1.7 × 1013 particles kg−1, respectively. The total emissions of CO, CO2, and NOx from rice, wheat and corn straw burnings in China for the year 2004 were estimated to be 22.59, 252.92, and 0.28 Tg, respectively. The percentages of CO, CO2, and NOx to the total emissions were 13.9%, 15.3%, and 31.4% for rice straw, 32.9%, 32.5%, and 20.9% for wheat straw, and 53.2%, 52.2%, and 47.6% for corn straw, respectively. In addition, the emission allocations of agricultural crop residue burning were also plotted in different regions of China using a simple geographic information system (GIS).