Nitrogen Oxide is a gas which affects air quality.

Carbon Dioxide is a gas which affects global warming.

Particulate Matter: solid and liquid particles suspended in exhaust gases which affect air quality.

Euro 5 standard from September 2009 – introduction of Particulate Filter.

Euro 6 standard from September 2014 – introduction of Selective Catalytic Reduction (SCR).

Diesel Exhaust Fluid (commonly known as AdBlueTM) - solution injected into exhaust to reduce NOx emissions.

Diesel Particulate Filter removes 99.9% of all particles before they leave the exhaust.

Selective Catalytic Reduction is an active exhaust gas after-treatment system reducing NOx.

New European Driving Cycle – is a laboratory testing method used for measuring emissions for vehicles and taxation policy.

Real World Driving Emissions - Revised EU6 emissions legislation that is designed to simulate real world driving.

WLTP (Worldwide harmonised Light vehicle Test Procedure) is the new process that has been phased in from 2017, which measures fuel, energy consumption, range and emissions and replaces the previous NEDC (New European Driving Cycle) driving cycle to measure fuel consumption and emissions in passenger vehicles in Europe. This is designed to provide figures closer to real-world driving behaviour. It tests vehicles with optional equipment and with a more demanding test procedure and driving profile. Differences in figures between the two testing regimes are due to a change in how the vehicles are tested, rather than a reduction in performance.

Ultra Low Emissions Zone – area in London where charges are imposed on pre-EU6 vehicles.