Automotive urea is a common product for heavy-duty diesel vehicles to meet the National IV emission standards. Automotive urea refers to a urea aqueous solution with a concentration of 32.5% and a solvent of ultrapure water. The raw materials are urea crystals and ultrapure water. Heavy duty trucks, buses and other diesel vehicles need to meet the National IV emission standards, and suitable SCR systems must be selected for exhaust treatment. This system requires the use of urea solution to treat nitrogen oxides in the exhaust. Therefore, urea solution for vehicles has become a common product for heavy-duty trucks and buses to meet the National IV emission standards.