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Since the 2010 passage of stricter federal regulations on nitrogen oxide (NOx) emissions in new diesel vehicles, the use of emission-reducing technology has skyrocketed. By far the most popular among these technologies is Selective Catalytic Reduction (SCR), which requires the use of a solution known as DEF. 
Diesel Exhaust Fluid, or DEF, is a high-purity urea-based solution designed to reduce NOx emissions in new diesel vehicles. NOx is a pollutant that contributes to the formation of smog and acid rain, which can damage our health and the environment. DEF is designed to be used in diesel engines equipped with SCR technology. When DEF is injected into the exhaust system of an SCR-equipped diesel engine, it reacts with a catalyst to break down NOx molecules into harmless nitrogen and water. DEF is an odorless, colorless, non-flammable and nontoxic solution that is harmless to people, equipment and the environment. High-purity DEF is increasingly available across the U.S. from companies like Airgas, which supplies ultra-pure AiRx DEF. | | 
Selective Catalytic Reduction, or SCR, is the leading emissions control technology available for diesel engines. SCR systems use a catalytic converter, with the addition of DEF, to break down NOx emissions. DEF is not a fuel additive, but a completely separate solution that resides in its own tank. First, it is injected directly into the exhaust stream, where it is then vaporized by a catalyst, forming ammonia. From there, the ammonia works in conjunction with the SCR catalyst to convert harmful NOx emissions into harmless nitrogen and water. | |