NOx (Nitrogen Oxide) Emissions Tax Explained

How changes to the emissions laws, which came into effect on January 1, might hit your wallet.

Changes to the way our vehicles are taxed have come into effect from January 1, meaning it could cost more money for you to buy the vehicle you’ve always had your heart set on. And we’re not just talking about new cars, either; these changes specifically apply surcharges on Vehicle Registration Tax (VRT), which is also payable on imports of second-hand cars.

The NOx Tax

The big change revolves around emissions. Our road tax and VRT laws have been heavily predicated on CO2 emissions, which favours diesel over petrol (mainly because diesels emit less CO2 compared to equivalent-power petrol engines). It’s why, for many years, diesel cars massively outsold petrol models in Ireland, because they cost a lot less to tax under the regulations that came into effect for cars registered from 2008 onwards.

However, in the wake of the Dieselgate saga, which began rumbling into life in late 2015, there has been a fresh look at emissions and just how beneficial diesels are to public health. This focused on oxides of nitrogen (NOx), which are more harmful to health. The interim policy of the government was to add a one per cent surcharge to the VRT paid on diesels, but that has been scrapped and replaced with an additional NOx tax to be paid on VRT for all new cars bar electric vehicles, meaning petrol, diesel and hybrid vehicles, as well as second-hand cars.

It is structured as follows. For the first 60 milligrams per kilometre (mg/km) emitted, the NOx tax is set at €5 per mg. The average NOx emissions figure of new diesels is roughly 43mg/km, so in many cases the cost incurred (€215) will be very similar to the outgoing 1% diesel surcharge. Above 60mg/km, however, the rate increases to €15/mg, and then from 81mg/km it jumps to €25/mg. There’s a cap of a maximum €4,850 for NOx tax on diesels, and just €600 for other vehicles.

Which cars will it affect most?

Those older diesels that don’t conform to the latest emissions standards, such as Euro 6d-TEMP and so on. This is the primary reason it has been brought in and so obviously weighted against old diesels, to stop the importation of the most polluting vehicles. As already said, diesels emit more NOx than petrol engines, as the average NOx emissions of a new petrol car are 23mg/km – so the bill there will be more like €115.

Obviously, as petrol cars (and, by extension, hybrids) were not previously privy to the 1% diesel surcharge on VRT, then there will be a slight increase in price for people buying new petrol and hybrid models. However, hybrids are particularly low on NOx, so should see only nominal NOx tax charges, while modern petrol engines are very clean too. Indeed, even second-hand petrol imports should get off OK, as they typically emit around 40mg/km, so should see a surcharge of €200. But older diesels, up and around the 80mg/km mark, will be looking at a €600 bill. It is therefore older diesel imports that will face the biggest penalties, making them less enticing to Irish drivers.

Any big winners?

Electric cars, obviously, as they are already privy to road tax and VRT breaks as a result of emitting no CO2 whatsoever. Well, EVs also emit no NOx nor other particulates, so they are not privy to the VRT NOx surcharge and continue to provide the cheapest running costs of all new (or used) cars.

How do I – and the government – know how much NOx my car emits?

The important number will be on the car’s certificate of conformity. Whatever NOx is listed there is what will be used to calculate the surcharge for a given vehicle. Cartell.ie’s free car check on UK registration numbers will also show the NOx levy.