A low-emission zone (LEZ) is a defined area where access by some polluting vehicles is restricted or deterred with the aim of improving air quality. This may favour vehicles such as bicycles, micromobility vehicles, (certain) alternative fuel vehicles, hybrid electric vehicles, plug-in hybrids, and zero-emission vehicles such as all-electric vehicles.
A zero-emission zone (ZEZ) is a LEZ where only zero-emissions vehicles (ZEVs) are allowed. In such areas, all internal combustion engine vehicles are banned; this includes any plug-in hybrid vehicles which cannot run zero-emission. Only battery electric vehicles and hydrogen vehicles are allowed in a ZEZ, along with walking and cycling and fully electric public transport vehicles, e.g. trams, electric buses etc.
Workings
In many LEZs, vehicles that do not meet the emission standards set by the LEZ are not barred from entry into the LEZ (i.e. using automated boom barriers), but rather simply fined if they enter the zone. A fine is not issued if entering the LEZ with a vehicle that does not meet the emission standards, when a fee (LEZ daily charge, ...) has been paid. In some LEZs, such as the one in London, this is done by automatic number-plate recognition (ANPR) cameras which read the vehicle registration number plate as they enter the LEZ and then compare it against a database of vehicles which: either meet the LEZ emissions standards, or are either exempt or registered for a 100 percent discount, or if the LEZ daily charge has been paid This fee/fine works as a deterrent for those having a vehicle that does not meet the LEZ emission standard for entering the city, and those having such vehicles will hence try to avoid paying this fee/fine (using various means, see "intent and actual impact").
Intent and actual impact
The intent of LEZs is generally to improve air quality within cities. This intent is indeed achieved, with diesel particulates (PM10) dropping in most LEZs, and health improving.
Often, this is achieved as people with polluting vehicles replace them with vehicles that attain a higher emission standard, which may mean buying a new vehicle, or travelling throughout avenues and roads distant from the areas where pollution is concentrated. Some people (such as workers on night shift or carrying heavy tools or cargo) however can't do without a car, but might not be able to afford to purchase unsubsidized cleaner vehicles. Therefore in some places the LEZ is only enforced when public transport is available, or electric taxis or cargobikes are subsidized.
The European Federation for Transport and Environment is of the opinion that LEZs should be gradually turned into zero-emission mobility zones and complement policies promoting a switch to clean alternatives, including walking and cycling, among others.
Most LEZs which are not also congestion charge zones do not change the number of vehicles entering the zone: but some LEZs (such as the one in Milan) double as congestion charge zones and thus have the potential to reduce the numbers travelling into the city.
Implementation by country
there are about 250 low-emission zones (LEZ), which help meet EU health-based air quality limit values. This means that vehicles may be banned from a LEZ, or in some cases charged if they enter a LEZ when their emissions are over a set level. Although common in Europe the continent's largest cities are lacking: Istanbul has no LEZ and Moscow's is not enforced.
Different vehicles may be regulated, depending on local conditions. All LEZs apply to heavy vehicles, some to diesel vans, others also to diesel and petrol cars; in Italy, motor cycles and three-wheelers are also liable to control.
A publicly funded website run by a network of cities and ministries operating or preparing LEZs gives up-to-date information on LEZs, such as which cities have LEZs, the vehicle types affected, the required emissions standards and their application dates.
Belgium
Antwerp: Since 2017, there has been a LEZ in Antwerp, 24/7. Only diesel vehicles above Euro 3/III norm and petrol vehicles above Euro 1/I norm are allowed to enter the LEZ. Brussels: Since 2018, the entire Brussels Capital Region has been a LEZ. Only diesel vehicles above Euro 4/IV norm are allowed to enter Brussels. Since 2019 petrol or gas-powered vehicles need to be Euro 2/II or more. Ghent introduced a LEZ on 1 January 2020.
China
An LEZ is present in Beijing.
Denmark
Denmark has LEZs that are applicable to vehicles over 3.5 t. In Denmark, LEZs exist in Aalborg, Aarhus, Copenhagen, Frederiksberg and Odense.
Finland
A LEZ is present in Helsinki.