AAll fuel-burning vehicles produce emissions. If you drive a diesel-powered car, the exhaust gases exiting the engine are laden with soot, ash, and nitrogen oxides that pollute the environment. Soot and ash are filtered out in the diesel particulate filter (DPF) system, but how are nitrogen oxides treated?
AdBlue is a urea-based fluid that initiates a chemical reaction to neutralize nitrogen oxides (NOx) in diesel exhaust fumes. It’s injected into the exhaust stream ahead of the Selective Catalytic Reduction (SCR) catalyst well before it exits the tailpipe. Ammonia in the AdBlue fluid mixes with and bonds to the NOx particles, reacting to break the gases down into harmless nitrogen and water. NOx gases are reduced by about 90% in vehicles equipped with these systems. Since the atmosphere is about 78% nitrogen, it’s clearly safer for the environment.
While it’s intended to reduce dangerous exhaust emissions, AdBlue is a system used on vehicles that must comply with Euro 6 diesel emissions standards. They’re the most stringent emissions standards in Europe yet, and they’re intended to improve air quality. All carmakers must meet Euro 6 standards for their new vehicles to be sold here. They’ve been in effect since 2014.
AdBlue is actually a trademarked brand name for the general term Diesel Exhaust Fluid (DEF). As early as 2009, some diesel cars were built that required AdBlue but it wasn’t commonplace until Euro 6 standards were implemented. The fluid itself is a mixture containing 32.5% high-purity urea and 67.5% demineralized water.