Why use the Green Car Rating?

1. The Green Car Rating includes all measured air-based emissions – not just CO2.

This allows a realistic comparison between different vehicle and fuel types – for example, while diesel typically has lower tailpipe CO2 emissions than petrol, diesel emissions include higher levels of NOx and particulates.

The emissions assessed are: carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), carbon monoxide (CO), oxides of nitrogen (NOx), hydrocarbons (HCs), particulates (PM), and sulphur dioxide (SO2).

2. The Green Car Rating includes lifecycle emissions, not just tailpipe emissions.

This enables a fair comparison of all conventional and alternative vehicle types – for example, hybrids offer better fuel economy, but also have higher manufacturing emissions.

It also means that zero-emission vehicles can be fairly assessed – while electric cars have zero tailpipe CO2, the Green Car ratings takes into account the emissions produced by electricity-generation and vehicles manufacture.

3. The Green Car Rating is an impact assessment, not just an emissions inventory.

Rather than just quantify the amount of each of the eight emissions, the Green Car Rating assesses by the environmental impact of the emissions.

Not only does this more accurately account for the impacts and location of different emissions, using the total environmental impact makes a comparison of eight emissions possible.

4. The Green Car Rating provides an easy-to-understand system for consumers.

The Rating is designed to used by non-experts and is therefore expressed as a score out of 100 ranging from 0 for the greenest vehicles to 100+ for the most polluting.