Overview of Measures
A wide range of measures can be taken to improve air quality. We have selected
nine categories of measures based on their potential to reduce particulate matter
(PM10) and nitrogen dioxide (NO2), pollutants for which the EU sets limits for local concentrations. The commitment to reduce these is a major motivation behind most cities’ air quality strategies. The categories have also been selected based on their potential to reduce soot emissions from traffic and non-road pollution sources. The purpose of the ranking is not to measure the reduction potential of the different measures. The aim is to highlight best practices and assess which of the 23 selected cities have made most use of them.
Several measures address the main emitters at source, for instance by introducing Low
Emission Zones and cleaning up public vehicles fleets or non road mobile machinery
such as construction machines. Other strategies such as economic incentives, traffic
management, and promotion of cycling and walking may reduce car use and thus improve
air quality. In addition, we looked at the reported reduction of local PM10 and NO2 emissions between 2008 and 2012 as well as at the level of public information and citizens’ participation in decision making.
Background concentrations of PM10 can’t be much influenced at
city level and requires national and even internationally
coordinating action. However, local traffic is responsible for a
significant amount of PM10 concentrations leading to violations
of EU limit values. We therefore compared the reported data of
traffic stations and background station between 2005 and 2009 …
Local Emissions Zones (LEZ) can be an effective way of reducing PM10 and
soot emissions. To be effective, a LEZ must be introduced early enough, should
be big in size, set ambitious emissions standards (Euro 4 and better) and be
strictly enforced. Bans of high emitters have the risk of only relocating
pollutants but not reducing them.
Municipal vehicles and buses cover big distances in cities and thus
become a relevant emission source. They can also serve as a role
model by setting the example. Retrofitting existing vehicles by
diesel particulate filters (DPFs) and furnishing new ones with
effective filters or other clean technologies would help reducing
their emissions …
Non Road Mobile Machinery (NRMM) is a major emission source which is
often overlooked. In some cities, it is responsible to up to 30% of
traffic pollution. Construction machines are in use many hours every
day and extended time periods. Vessels and railways are other emitters
which should be equipped with particle filters if they operate in cities …
Road or congestion charges have proved to lead to important reductions.
Revenues can be used for investments in environmentally friendly modes
of transport. Other economic incentives can also be introduced through
What has been the modal split trend during the last five years?
The ranking looked into reductions of personal motorised transport
as well as possible targets for the coming years. Some cities are
developing innovative mobility management measures aimed at
citizens but also companies, schools or universities …
Measures to raise the share of public transport can reduce car use
and improve air quality. The ranking looked into investments for
expansion of public transport networks and other tools promoting
public transport. We looked at the measures implemented over the
last five years as well as solid plans to do so in the future …
Hard (infrastructure) and soft (communication) measures were looked
into and compared. We assessed whether the measures were ambitious
enough and whether their success was documented. We considered
future plans when they were concrete with solid political and
financial support …
This category looks both at the public participation in decision
making and the level and quality of information available to the
public. The level and quality of information was assessed based on
wide range of criteria e.g. whether online information tools were
sufficient and updated or whether air quality plans were easily accessible.
Public participation in decision making has also been assessed.