by Ivan K. Makoku, Director(AirNox Pty Ltd) | August 1, 2022

What is AdBlue®?

Household name in some modern diesel

AdBlue® is fast becoming a household name in some modern diesel cars/trucks/buses, with reports of its supply shortage in several parts of the world since the beginning of 2020. A quick look at AdBlue® will first reveal its other names depending on different regions. For example, one will find it as AdBlue® in European, Asian and African countries, Arla32 in Brazil, and DEF (Diesel Exhaust Fluid) in the US.

The existence of AdBlue® traces back a few years back, in 2009. However, only recently, in 2015, AdBlue® started being fitted in some new vehicles using diesel engines. But even while its cameo in the automotive industry was realized, many still do not know what AdBlue® is, what the component entails, why the diesel engines need it, its benefits, refilling AdBlue®, consequences of running on low AdBlue®. This guide seeks to answer of what is AdBlue® – related questions!


AdBlue® (DEF)

AdBlue® is simply a toxic-free, colourless diesel exhaust fluid sprayed in the catalytic converters of some diesel engine exhaust systems to ensure the breakage of harmful nitrogen oxides by burning the exhaust gases at high temperatures. Its inception was to counter the challenges of global warming, in some sense, by lowering the toxic emissions from diesel vehicles. AdBlue®, as a component, is a mixture of urea and deionized water.

Deionized water is water purified with most of its mineral ions like copper, calcium, sodium, iron, and anions such as sulphate removed. It is achievable through treatments like reverse osmosis to ensure the proper elimination of contaminants.

A point to note is that distilled water is not deionized water since the former includes boiling the water to ensure purifying the water free from impurities and contaminants.

The question of why some diesel vehicle manufacturers uses AdBlue® is to adhere to several rules, including addressing environmental concerns. For example, Euro 6, introduced in September 2015, represents some stringent European emission standards implemented. The standards call for all new vehicles in the market to emit lower pollutant levels, including NOx (Nitrogen Oxide), a health hazard for people in urban settlements.

Diesel engines produce more NOx levels than petrol cars, with Euro 6 standards calling for 80mg/km NOx levels compared to 180mg/km permitted in the previous Euro 5 standards.

With going purely green seemingly proving a big ask in the ever-growing world, the introduction of AdBlue® in the diesel engines adheres to the Euro 6 standards while also helping reduce CO2 emissions released daily on the roads.

Note: It is a legal requirement to use AdBlue® on diesel vehicles fitted with SCR (Selective Catalytic Reduction) technology.


Euro Emission Standards

Besides the Euro 6 standards, looking at the other standards is important to understand the AdBlue® journey to the present world. The objective of the vehicle emission standards was/is to reduce pollution across European countries.

Euro 6 is the latest emission standard, and all vehicles after September 2015 that meet the targeted amount of NOx emissions set at 80mg/km in Euro 6 standards have lower vehicle tax rates in Europe, making them attractive compared to the pre-2015 vehicles. The timeline from Euro 1 to Euro 6 is as follows:

♦ 1956: The German government sought from German Engineers the guidelines they could put in place to reduce emissions.
♦ 1961: A team of engineers from Germany and France agreed on a protocol for standardization.
♦ 1970: The first car emission standards were introduced in the EEC (European Economic Community).
♦ 1982: The emissions levels were down by over 50% since 1970. The EEC sanctioned additional regulations to evaluate the health effects of exhaust emissions and smog. This gave birth to the Evolution of Regulations – Global Approach (EGRA).
♦ 1992: Euro 1 was introduced with the requirement that all new petrol engine vehicles fit catalytic converters to reduce CO2 (Carbon Monoxide) emissions.
♦ 1996: Euro 2 was introduced further limit the carbon monoxide levels and unburned hydrocarbons and nitrogen oxides for vehicles (petrol and diesel).
♦ 2000: Euro 3 was introduced with the test procedure modified to do away with the engine warm-up period. This led to further reduction of CO limits, separate NOx limits (diesel engines), and hydrocarbon and nitric oxide limits (petrol engines).
♦ 2005: Euro 4 was introduced with diesel vehicles reducing particulate matter nitrogen oxide (NOx). The vehicles were also fitted with particulate filters.
♦ 2009: Euro 5 was introduced, with the regulation tightening the limits on emissions from diesel vehicles. This birthed the reduction of NOx limits by 28% from the limits on Euro 4.
♦ 2015: Euro 6 was introduced with the regulation imposing additional reductions in NOx emissions from diesel engines. This went a notch higher to reduce NOx limits by 67% from the Euro 5 limits.


 AdBlue® Composition

Let’s get a bit more technical, shall we? The first myth we need to bust is concerning the ingredients in AdBlue®. Many people believe AdBlue® is a composition of pig urine, while others believe it is a fluid made up of a highly dangerous chemical. Both are untrue.
Our earlier explanation showed that AdBlue® is a mixture/solution of high-purity urea and deionized water. The composition is as follows:

♦ Technical Grade Urea: 32.5%
♦ Deionized water: 67.5%

The urea solution is usually water-based and poses no human or environmental risk. On the other hand, the solution is non-flammable.


How Does AdBlue® Work?

In a nutshell, by using AdBlue®, components like nitrogen (N2), carbon dioxide (CO2), and water vapour (H2O) get released through a process called Selective Catalytic Reduction (SCR), where harmful gases like nitrous oxides (NOx) get converted to inert products and leave a clean exhaust stream. The whole process ensures the environment gets cleaner and safer.

Is There Any Risk Of AdBlue® Getting In Contact With The Diesel Tank?

The answer is no. Vehicle manufacturers ensure that AdBlue® has its separate tank with a unique sensor system and gauge on the dashboard to ensure drivers can track their AdBlue® levels and even know when to refill. Immediately after combustion, the fluid gets sprayed into the exhaust stream just before the SCR catalyst for cleaner emissions that are environmentally friendly.

How are cleaner emissions achieved? While heating in the exhaust system, AdBlue® will decompose to ammonia and CO2. On the other hand, when the NOx from the engine exhaust reacts inside the SCR catalyst with ammonia, the NOx molecules convert to environmentally friendly nitrogen and water, released as steam from the tailpipe. It is worth noting that unlike diesel injected into the engine, AdBlue® gets fed into the exhaust system instead.


Vehicles Using AdBlue®

AdBlue® fluid’s popularity is mostly on heavy-duty trucks, vans, buses, SUVs, and the some of the latest diesel vehicles produced by top vehicle manufacturers like Ford, Toyota, Renault, Citroen, Volkswagen, Mazda, Audi, Land Rover, Peugeot, Jaguar, Mercedes Benz, and BMW.


Here are some of the car models using AdBlue®:

♦ Audi: A6 Avant, A5 Sportback, and Q7 diesel options, A7 Sportback, A8, Q3, and A4 Saloon.
♦ BMW: X5, X6, Series 5 Saloon, and Series 7 Saloon.
♦ Citroen: C3, C4 Cactus, and Berlingo Multispace.
♦ Fiat: Ducato Series 7
♦ Ford: Transit and Everest variants
♦ Land Rover: Land Rover Discovery, Defender 90, Defender 110, Range Rover Velar, Range Rover Evoque, Range Rover Sport, and Discovery Sport.
♦ Volkswagen: Passat, Passat Alltrack, Caravelle, Transporter, Tiguan, Caddy, Toureg, and California.
♦ Peugeot: 2008 & 3008 SUVs, 5008 people carrier, Traveller, 208, 308, and 508 models.
♦ Toyota: Toyota Land Cruiser
♦ Mercedes Benz: C-Class, E-Class, S-Class, GLC, GLE, G-Class, CLS, and Sprinter.
♦ In a nutshell, most of the latest diesel engine vehicles use AdBlue® for NOX reduction.

Do I Need AdBlue® To Run My Vehicle?

Your vehicle may or may not need AdBlue® to run. As stated, AdBlue® is only usable on diesel vehicles, thus negating the use of the same on any petrol engine. Secondly, while you might own a diesel car, only the most recent vehicles are most likely to use AdBlue®.

An interesting point to note for vehicles using AdBlue® is that the fluid does not play any part in making the engine work. However, with vehicle manufacturers required to stick within the legal requirements stipulated in Euro 6 standards, the vehicle manufacturers program the vehicles to stop if there is insufficient AdBlue® or lack thereof. Remember, while running low on AdBlue®, you should have the display on your dashboard.

How To Check If Your Vehicle Uses AdBlue®

While one might be uncertain about whether their vehicle uses AdBlue®, we at AirNox make it easy for you. The most straightforward ways to check whether your vehicle uses AdBlue® will include the following:

♦ Check the car manual handbook provided on purchase.
♦ Open the fuel filler cap to check for a separate AdBlue® filler cap.
♦ Check if the car/truck/bus model contains ‘SCR’ or ‘Blue.’
♦ If unsure still, get clarification from the dealer.

AdBlue® Consumption

Like the diesel storage tank, the AdBlue® storage tank is big enough to store AdBlue® that can run for a while before a scheduled servicing/refilling. Your vehicle will automatically use AdBlue® at the required amount, depending on your driving behaviour. AdBlue® usage is typically between 4% to 8% of diesel used for commercial vehicles.

For every 100 litres of diesel used, you will need four (4) to eight (8) litres of AdBlue®.

On the other hand, the average use of AdBlue® for passenger cars is 1.5 litres for every 1000km. The AdBlue® warning light will come on when you have about three (3) litres left which should be enough to drive for approximately 2000km. The 2000-2400km driving range should be enough for an average customer to order AdBlue® online at: or Don’t hesitate to contact for international customers interested in buying AdBlue® in bulk.

What Happens If AdBlue® Runs Out While Driving?

Running out of AdBlue® while driving means that the vehicle’s performance and power get limited to ensure lower emission levels. However, it gets worse if AdBlue® runs out completely. Immediately after switching off the vehicle, you will not be able to restart the engine until you refill the AdBlue®.

But, before getting to this stage, the vehicle will display plenty of warnings on the dashboard that AdBlue® is running low (approximately 1500 miles/2400km). This gives the driver ample time to refill the tank before running out. AdBlue® tanks vary in size depending on the vehicle manufacturer and configuration, they vary between 8L to 25L for passenger cars and 30L to 100L for commercial vehicles.

What Happens If AdBlue® Gets Into The Diesel Tank?

In case of the unfortunate experience of putting AdBlue® in the diesel tank, the first rule is to not turn on the ignition key. Switching on the vehicle means that the AdBlue® fluid flows to the engine and can easily corrode the fuel lines, including the fuel pump, injection system and tank. It would become expensive to repair the mentioned just by turning the ignition key on.

Instead, you will need to drain every content in the fuel tank safely before refilling the tank. Please get in touch with your manufacturer for further guidance and support.

Note: AdBlue® is not a fuel additive and must not come in contact with diesel.


Topping Up AdBlue®

Topping up AdBlue® is as easy as refilling your diesel tank. However, while filling, drivers should ensure to wash any part of the car affected by any AdBlue® spill. The reason is that while AdBlue® is non-hazardous, it is corrosive and can dissolve several materials not listed in ISO 22241. Drivers should also consider using hand gloves while dispensing AdBlue® to keep their hands clean.

In some other parts of the world, several gas/petrol stations have AdBlue® pumps where drivers can directly fill their AdBlue® tanks. It is the easiest and most convenient option since one gets to refill whenever the vehicle prompts them to do so. The other option is to acquire AdBlue® from authentic suppliers such as AirNox ( / / ). You can store the AdBlue® safely for up to twelve (12) months in temperatures between -11 degrees Celsius and 30 degrees Celsius. Wondering where to store bulk AdBlue® for commercial customers? You can easily purchase an AdBlue® storage tank from AirNox by contacting our customer service team.

AdBlue® Cost

AdBlue® was relatively cheap pre-covid-19. However, the prices have skyrocketed post-covid-19 due to the shortage of raw materials and the global supply chain crises. While pricing may fluctuate depending on the technical grade urea production cost and supply chain crises, AirNox ensures that its prices remain competitive, and we have a price match policy for our products worldwide, whether in small or bulk quantities. Our packaging quantities include 5L, 10L, 20L, 210L, 1000L, Flexitanks, and Bulk deliveries.


♦ AirNox is a leader in AdBlue® production, having the capacity to supply AdBlue® to South African customers online by contacting:
♦ If you are contacting us from other African countries, don’t hesitate to contact us at
♦ For all international customers, please get in touch with us at


To sum it, and with a clear picture of what AdBlue® is, the following are the benefits of using AdBlue®:

♦ Efficient driving experience: Running on low AdBlue® does not maximize the engine power or performance, thus limiting the driving experience.
♦ Environment friendly: The main objective of using AdBlue® is to reduce harmful emissions of nitrogen oxide (NOx), which are harmful to the environment and people.
♦ Fuel consumption: While it remains debatable, the use of AdBlue® in vehicles enables the optimization of combustion, which in turn lead to a considerable amount of reduction in fuel consumption by average of 5% depending on the size of the engine and the driver behaviour.