CFD Modeling of Tractor Emissions in the Near-Field: Implications for Occupational Health and Agro-Environmental Quality

The operation of walking-type agricultural tractors (WTATs) emits exhaust gases, which may pose health risks to operators from extended exposure. Comprehending the dispersion characteristics of these emissions is crucial for formulating effective safety protocols. This study evaluated the near-field spatial distribution of carbon monoxide (CO) emissions from a WTAT through experimental measurements and computational fluid dynamics (CFD) simulations, considering different throttle settings, relative wind speeds, and wind angles of attack. The findings indicated that throttle settings had a significant impact on the concentration of CO emissions produced by the engine. A reduction of approximately 86% in CO concentration was observed within 20 cm from the exhaust outlet. At elevated relative wind speeds, the CO plume exhibited a tendency to disperse in alignment with the airflow direction, directing emissions toward the far-left side of the operator while maintaining a low risk of exposure, irrespective of forward speed. Ambient wind angles ranging from -15° to -30° were identified as critical, as emissions were directed toward the operator's body, thereby increasing potential exposure. The CFD model demonstrated strong agreement with experimental data, particularly at reduced forward speeds, and effectively identified critical exposure zones. This study advocates for the utilization of personal protective equipment, including safety masks, during field operations to reduce health risks linked to inhalation of exhaust gases.