Determining exhaust emissions (CO, NOx, PM) for a combine harvester based on measured engine load and emission factors using PEMS during actual field operation

Global concerns about climate change and air pollution have led to stricter environmental regulations, with a growing proportion of air pollutant emissions coming from non-road mobile machinery. Controlling emissions from agricultural machinery, particularly large equipment like combine harvesters, is crucial. However, South Korea's emission estimation factors for agricultural machinery are based on indoor experiments and do not fully reflect actual operating conditions. This study used a portable emissions measurement system to assess the engine load and exhaust emissions of a combine harvester in real-world conditions. The unified load factor measured was 0.63, approximately 31.3 % higher than the conventional value of 0.48. Average emission factors for CO, NOx, and particulate matter (PM) were (0.5048, 0.4130, and 0.0042 g/kWh, respectively) 85.3 %, 93.5 %, and 79 % lower than the standards of 3.44, 6.36, and 0.02 g/kWh, respectively. Final emission calculations using the improved load factor and emission factors showed an 84 % reduction in CO, a 92 % reduction in NOx, and a 99 % reduction in PM compared to those calculated using current factors. Emission factors based on actual working conditions are expected to improve the reliability of the combined-harvester emission inventory.