What is the function of adding urea to trucks?

[Etta]

Truck urea injection is primarily used for exhaust treatment. Only vehicles equipped with diesel engines require urea addition, mainly to treat exhaust gases and reduce pollutants in the emissions. Most vehicles using diesel engines, such as buses, trucks, semi-trailers, and trucks, are required to add urea. Urea injection is specifically for diesel engines because they emit nitrogen oxide (NOx) pollutants during operation, which are harmful to both the atmosphere and human health. Prolonged exposure to these gases can cause respiratory diseases. To mitigate these hazards, urea is utilized in a catalytic reaction process. When urea encounters nitrogen oxides emitted from diesel engines, a chemical reaction occurs that converts the NOx into harmless nitrogen and water vapor. Typically, about 4 liters of urea are consumed per 100 liters of diesel fuel. The exact consumption rate varies depending on engine displacement, model, manufacturer, as well as road conditions and load capacity.