Reducing transport emissions

Decreasing air pollution from traffic

Develop further or introduce policies to reduce air, soil and water pollution, accidents and noise, greenhouse gas emissions and the damaging of forests associated with transport and its infrastructures (airports, motorways, railways, terminals, harbours, petrol stations, etc.), in similar ways to other major industrial sources.


Transport is a major source of air pollution. Most types of transport consume fossil fuels. The automobile is the biggest polluter.

In order to reduce as much as possible transport emissions of and human exposure to air pollutants identified in WHO's air quality guidelines as having no safe limits (these include particles, identified hazardous volatile organic compounds (VOCs) like benzene, and persistent organic pollutants such as polyaromatic hydrocarbons, dioxins, furans and polychlorinated biphenyls), it will be necessary to: (a) reduce emissions of and human exposure to CO, NO2 and SO2 where transport is a major contributor; (b) lower ambient ozone concentrations by reducing emissions of VOCs and NOX from transport; (c) reduce exposure to fine and ultrafine particles from transport by setting targets that take into account recommendations to be developed by WHO regarding the number, mass, size, surface area and composition of these particles; and (d) reduce human exposure to transport-related lead emissions by phasing out leaded petrol, in line with the Ã…rhus Declaration.


Because continuous monitoring of individual emissions from transport is currently considered virtually impossible, there is no emission tax that can be applied easily and efficiently. Indirect policies to reduce transport emissions are used. They include decreasing overall demand for travel, shifting travel demand towards less-polluting or less fuel-intensive modes of transport by, for instance, car-pooling and increased public transportation, and reducing emissions per kilometre driven. The USA has almost exclusively adopted the latter strategy, principally by the imposition of emission standards on all new vehicles and the requirement of vehicle inspections. In recent years, unleaded petrol has been introduced. Athens and Mexico City suffer particularly from air pollution caused by vehicle emissions. Both cities restrict driving in the urban centre according to license plates, though this encourages evasion.

ALTER – Alternative Traffic in Towns – aims to help tackle traffic congestion by allowing access to parts of cities only for cleaner vehicles and by signing up to convert council vehicle fleets to cleaner models and fuels. All European cities with a population of 100,000 or more are invited to take part in ALTER. Six cities – Athens, Barcelona, Florence, Lisbon, Oxford and Stockholm – have been designated as lead authorities. Mayors of participating cities will sign up to a declaration to improve air quality in cities and to action, including designating clean air zones, which prioritise road space in the cities for low emission vehicles. This will generate demand for cleaner vehicles and reduce their cost.

ALTER aims to get European cities to agree to 3 key principles: (a) to renew, as soon as feasible, their own transport on clean or near zero basis; (b) to convert, where practical, those of their vehicles with extended lifetimes to lower emission or cleaner fuel; and (c) to introduce ,and progressively extend, areas of their cities to which only traffic with clean or near zero emission vehicles have access.

The Declaration of the Third Ministerial Conference on Environment and Health (June 1999) states: We will strengthen the enforcement of current legislation and strive to implement the measures in the Charter's plan of action, especially those aimed at attaining the health targets, and to integrate health and environment concerns into current and new transport, water and land use planning policy, inter alia by: (a) pursuing cooperation and promoting approaches whereby health and environment requirements are taken into account and authorities in both sectors are involved in decision-making processes related to transport, water and land use planning and infrastructure; (b) promoting modes of transport, such as public transport, walking and cycling, and water, land use planning and technologies that have the best public health impact; (c) assessing the environmental health impacts and costs of transport, land use and infrastructure policies and investments; (d) promoting policies designed to internalize transport-related environmental health costs; (e) developing policies to protect populations at extra risk of health effects from transport; (f) investigating further the health risks from transport that are not yet fully clarified; (g) monitoring the links between transport and health and the progress made towards the targets identified in the plan of action; (h) promoting pilot projects and research programmes focused on achieving transport that is sustainable for health and the environment; (i) raising public awareness and individual responsibility and ensuring access to information about the impacts of transport on environmental health, and increasing public participation in decision-making on transport projects and strategies; and (j) cooperating with and giving all possible support to countries with severe transport-related health problems in promoting transport sustainable for health and the environment.

Type Classification:
D: Detailed strategies
Related UN Sustainable Development Goals:
GOAL 7: Affordable and Clean EnergyGOAL 11: Sustainable Cities and Communities