The EQUA Air Quality Index

What is the issue?

The EQUA Air Quality Index is the independent authority on how car emissions affect air quality. Poor air quality is a serious issue in many locations, contributing to some health problems. All vehicles running on diesel or gasoline emit air polluting nitrogen oxides (NOx), but the amount varies significantly from car to car.

Official figures do not allow an easy, clear comparison to be made between different cars in real on-road driving.

Without the right data, it is impossible to make an informed decision on the best car to buy. While diesels typically have the best fuel consumption, are the emissions of pollutants just too high to justify the purchase?

The Volkswagen emissions scandal has made car pollutant emissions a hot topic, but it has left confusion. Are all diesels dirty? Are all Volkswagens well over the regulated limits?

How the EQUA Aq Index helps

The EQUA Index seeks to sort the good from the bad in a simple, clear way.

The EQUA Air Quality Index clearly identifies vehicles emitting the lowest quantities of nitrogen oxides (NOx) on a scale from A (best) to F (worst).

A comprehensive list of all ratings issued so far can be accessed above. These are free for download, distribution and publication in the format provided.

Ratings Explained

Rating Lower bound1 Upper bound2 External reference point
A 0.00 0.02 Meets California LEVII SULEV standards
B 0.02 0.05 Meets California LEV II LEV and ULEV and EPA Tier 2 Bin 5 (both 5yr/50k mile)
C 0.05 0.07 Meets California LEV II LEV and ULEV and EPA Tier 2 Bin 5 (both 10yr/100k mile)
D 0.07 0.20 Meets California LEV I LEV (5yr/50k mile)
F 0.20
Units: g/mi, 1 exclusive, 2 inclusive