The AIR Index

What is the AIR Index?

What is the AIR Index?

The AIR Index is an independent emissions rating for cars from A (the best) to E (the worst) that provides the on-road urban NOx emissions using the same independent test on every vehicle, to show the relative impact a specific vehicle has on air quality.
The A-to-E rating is based on the results of vehicle tests conducted for AIR and carried out on-road, by approved, independent testing organisations. At least two different cars of each model, sold and on the road, are sourced independently from the car makers to ensure that the rating represents the actual emissions produced during town and city driving. Read more about our testing process.

Vehicles rated A in the AIR Index produce the lowest level of NOx emissions and the scale ranges in bands down to E for vehicles emitting the highest level of NOx emissions. The tests are carried out according to the latest international protocol CWA 17379, providing access to an independent and trusted source of data. The AIR Index is free to use and the results provide key information about each vehicle including the emission rating A-to-E, along with the published data for CO2 emissions and the Euro rating. AIR has commissioned an ongoing programme ofvehicle tests and new results are constantly being added to The AIR Index.. The data provided in The AIR Index can be filtered in multiple ways, for example to find all vehicles by a rating A- to- E, by vehicle class, CO2 emissions and so on. Data is also available for policy makers and fleet managers to integrate with planning tools through an API. Explore the emissions ratings and search the AIR Index.

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Why It Matters

Confusion about the vehicle emissions produced on-road compared with lab tests is a major barrier to improving air quality

Air quality in towns and cities will improve immediately by choosing and using cars with the lowest NOx emissions, but who can tell you which vehicles are the cleanest? Pure electric vehicles produce no NOx emissions and will ultimately replace hybrids, diesel and petrol, but we can’t wait a decade or more to clean up the air we’re breathing today.

Our trust in air quality data produced from laboratory tests of vehicles has been squandered by car makers through scandals such as ‘Dieselgate’ and still casts a long shadow today. The results from some of the latest Euro 6 emission tests show significant differences between NOx emissions measured in lab conditions and those produced driving through towns and cities. The development of the AIR Index has been led by a global alliance of scientists and organisations committed to reducing harmful vehicle emissions by providing car buyers and policy makers with a trusted and independent way to evaluate each car model. The clear, internationally agreed methodology, independent testing and A-to-E rating enables decisions to be made about vehicle choices by consumers and provides the basis for a legal framework to allow access for the cleanest cars to towns and cities by policy makers based upon the actual on-road emissions of vehicles tested. Using the AIR Index when buying a car or setting emissions policies can improve air quality, now. Explore how AIR rates vehicle emissions and search the AIR Index.