State the two main exhaust gas pollutants generated by a compression ignition diesel engine?

The two main exhaust gas pollutants generated by a compression ignition diesel engine are nitrogen oxides (NOx) and particulate matter (PM). NOx is formed during high-temperature combustion, contributing to smog and acid rain, while particulate matter consists of tiny soot particles that can harm respiratory health and the environment. Additionally, unburned hydrocarbons and carbon monoxide can also be present but are typically considered secondary pollutants in diesel engines.