Impact of LEZs

As a number of LEZs have now been operating for over a year, it is becoming possible to assess the actual impact. The bottom of this page gives some of the results for Berlin, the Netherlands, London and Cologne, as well as in more detail for for Stockholm that has been in operation for longer - information for 13 LEZs in 4 countries.

Further below more detailed information with maps for impact of Londons LEZ from the feasibility studies undertaken before it was implemented.

Results since implementation:

Berlin LEZ:

• Since January 2008. In April 2009 the LEZ reduced emissions of diesel particulates by 24% and Berlin’s PM₁₀ by 8%.
• Reduced: PM₁₀ exceedences from 28 to 24 per year, diesel particulate concentrations by 14-22%, & PM₁₀ concentrations by 3% on main roads.
• The second phase of the LEZ will have a greater impact.

Netherlands LEZ, in 9 cities:

• From January 2007. In summer 2008, the actual air quality improvements were slightly less than predicted, with improvements between 0 - 2μg/m ³.
• Impact limited by gradual enforcement and many exemptions for vehicles where diesel particulate filters were not available.
• Both of these will improve and expect to increase the air quality impact by a factor of 1.5 - 2. The LEZ second phase will also increase the impact.
• Since the report was undertaken, the Dutch enforcement of LEZs is strengthening. A recent enforcement drive to increase the effectiveness of the LEZs. In Den Bosch 83% of lorries complied – up from 70%. In Eindhoven 91% of vehicles now complied. Vehicles which did not comply and did not have exemptions were fined the € 150 fine. This increased compliance will increase the impact of the LEZ on air quality.

London LEZ:

• Since February 2008. First phase expected to reduce the area over the 2010 PM₁₀ Limit Values by about 5.8% in 2008.
• Feasibility study predicted gain of 5200 years of life, and the avoidance of: 310,000 cases of lower respiratory symptoms, 30,000 cases of respiratory medication & 231,000 restricted activity days for all phases. 
• Cost Benefit Analysis £250-670 million benefit, £90-250 of which are outside Greater London.
• In the first week 50,000 vehicles over 12 T were observed, 91.5% of which complied. In January it had been 75% and in April it was over 95%.

Cologne

• Since January 2008. Results from the first year of operation show that air quality concentrations in Colognes LEZ have reduced more than the surrounding background. For NO₂ by 1.2 μg/m³ (background reduction was 0.5μg/m³), PM₁₀ by 4 μg/m³ and 17 exceedences of the limit value (background reduction 4 μg/m³ and 7 exceedences). 

Stockholm

The Stockholm LEZ has been in operation since 1996, and its impact was estimated in 2000. The impact on emissions of particles (PM₁₀) and nitrogen oxides (NOx) are given below.

PM₁₀ emissions                                                                NOx emissions

Since 2000, there has been further work in Stockholm to reduce illegal vehicles (those not meeting the standards), and illegal vehicles are now less than 5% of those entering the zone. The contribution of emissions from illegal vehicles will be less than is estimated here.

In looking at the impact on concentrations, the levels of PM_0.2 (particles less than 0.2 μm in diameter) have been estimated. These are some of the smallest particles that are of most concern to health. Since diesel particulate exhaust emissions are all PM_0.2, they are reduced by the LEZ. The map below represents the estimated percentage reduction in PM_0.2 concentrations in Stockholm due to the LEZ.
 

As can be seen from the variations in colour across map, emissions reduce differently in different parts of the city, depending on how heavy the traffic is, and therefore the impact of having cleaner lorries. The data represented in the map above shows that concentrations of PM_0.2 were reduced by between 0.5 and 9%, with the LEZ, compared with what it would be with no LEZ. If all vehicles had been fully compliant, then the concentrations would have been reduced by between 0.5 and 12%.

Results from feasibility studies
Greater London
The London LEZ started on 4th February 2008. A lot of work was done before it was implemented on estimating the impact of the LEZ.

The map below shows what NO₂ concentrations in London would be in 2010 without the LEZ, measured in µg/m³, with yellow and above being over the EU air quality targets which indicates the size of the problem that the LEZ needs to deal with. Note the scale of the map of Greater London - the area covered is 1600km².

 
The tables below give estimations of the areas that do not meet the EU air quality targets due to the LEZ, and the population living in those areas.