In this study, the effects of engine speed, air-fuel ratio, combustion timing, intake-air temperature, and coolant and oil temperature on exhaust gaseous emissions (nitric oxide, carbon monoxide and hydrocarbons) and particulate emissions (particulates, volatiles and smoke) were investigated in a single-cylinder, divided-chamber diesel engine. In addition, the trade-off behavior of the pollutants was investigated. To aid in the interpretation of the experimental findings, a single-chamber, single-zone heat release model utilizing experimental main-chamber pressure-time data was employed. The large increase in nitric oxide emission index caused either by increasing the air-fuel ratio or by advancing the combustion timing is attributed to the proportionally larger amounts of fuel that burn at near TDC conditions. The increase in hydrocarbon emission index with increasing air-fuel ratio and with retarding combustion timing is believed attributable to the resultant increase in bulk quenching. Particulates and smoke increased with decreasing engine speed, increasing load, and advancing combustion timing. In contrast, the volatile content of particulates increased with decreasing load and retarding combustion timing.