AdBlue® is a high-purity solution of 32.5% urea in de-ionised water, used in modern diesel vehicles to cut harmful emissions. Here's what it does, how it works, and why quality matters.
AdBlue® (also called Diesel Exhaust Fluid, or DEF) is a clear, non-toxic liquid — 32.5% urea and 67.5% de-ionised water — stored in a separate tank on your diesel vehicle. It is not a fuel additive and never goes in the fuel tank. Its quality is defined by the international standard ISO 22241.
Modern diesel engines use Selective Catalytic Reduction (SCR). A small amount of AdBlue® is injected into the hot exhaust, where it converts harmful nitrogen oxides (NOx) into harmless nitrogen and water vapour:
Breaks NOx down into nitrogen and water — dramatically cleaner exhaust.
Required for Euro 5/6 and modern SCR diesel engines to meet emissions rules.
Correct-spec AdBlue® keeps the SCR system and sensors running trouble-free.
AdBlue® is sensitive to contamination. Off-spec or dirty product can clog injectors, trigger warning lights, and cause expensive SCR damage. That's why Liquidia manufactures to ISO 22241, is VDA-licensed, and lab-tests every batch — so what reaches your tank is genuine, high-purity AdBlue®.
• Store between −11°C and 30°C, out of direct sun.
• Use clean, dedicated equipment — never funnels used for fuel.
• Keep containers sealed; shelf life is typically 12–18 months.
• Only use ISO 22241 / VDA-certified product.
AdBlue® — also called diesel exhaust fluid (DEF) or AUS 32 — is a clear, non-toxic solution of 32.5% high-purity urea in de-ionised water. It is not a fuel additive: it is stored in a separate tank and injected into the exhaust, where Selective Catalytic Reduction (SCR) technology uses it to convert harmful nitrogen oxides (NOx) into harmless nitrogen and water vapour. Its quality is defined by the international standard ISO 22241.
As emissions standards tighten — Euro 5, Euro 6/Euro VI and the upcoming Euro 7 — SCR and AdBlue® have become essential to keeping modern diesels legal and running. Using genuine, certified AdBlue® protects the SCR system; contaminated or off-spec product can trigger warning lights and expensive repairs. That's why Liquidia manufactures VDA-licensed, ISO 22241 AdBlue® and lab-tests every batch.