Final answer:
A Selective Catalytic Reduction (SCR) system attempts to reduce NOX emissions in exhaust gases by converting them into harmless nitrogen and water vapor.
Step-by-step explanation:
A Selective Catalytic Reduction (SCR) system attempts to reduce NOX emissions in exhaust gases. NOX refers to nitrogen oxides, which are formed when atmospheric nitrogen reacts with oxygen at high temperatures in combustion engines. SCR systems use a catalyst to convert NOX into harmless nitrogen and water vapor, thereby reducing air pollution.