EN Official Journal of the European Union CE 78/47

(2004/C 78 E/0045)

WRITTEN QUESTION E-1817/03

by Christopher Huhne (ELDR) to the Commission

(2 June 2003)

Subject: Air pollution

Will the Commission state the typical air pollution resulting from the emissions of a passenger vehicle, light van and goods lorry in each case while idling in a traffic queue and while running at typical cruising speeds?

Answer given by Mrs Wallström on behalf of the Commission

(4 August 2003)

The same amount of emissions from a vehicle can cause rather different levels of air pollution depending e.g. on the weather (wind speeds, presence of an inversion layer etc), on the insolation (ozone formation) and on the topography (e.g. street canyons). This is why the Auto-Oil programme used a simulation programme, Tremove, in order to model the impacts of pollutant emissions in a number of different European cities. The proposals for emission limit values for motor vehicles that the Commission then produced were based on these calculations. It is thus not possible to define ‘typical’ levels of air pollution resulting from emissions.

The levels of emissions of air pollutants are much more readily understood than the pollution they cause, because they can be directly measured. They are thus used in the type approval procedure for motor vehicles. However, it is difficult to identify ‘typical’ cruising speeds, which is why the legislation for light-duty vehicles (cars and vans) makes reference to a drive cycle that is intended to simulate real-world driving. The emission limit values laid down in Directive 1998/69/EC (1) (in terms of grams per kilometre) are, therefore, a good indication of the air pollution produced by light-duty vehicles.

The situation is somewhat more complex for heavy-duty vehicles where the emissions are being measured not per kilometre driven but per unit of work done by the engine (grams per kilowatt-hour). The corresponding emission limit values are laid down in Directive 1999/96/EC (2). The emissions on a per-kilometre basis would differ markedly between different types of lorries, e.g. because the same kind of engines are used for very different types of heavy-duty vehicle, and because the load can vary significantly. A simulation model such as Tremove would be required to obtain values on a per-kilometre basis.

The idling state of the engine is part of the drive cycle used for the type-approval of passenger cars. The emissions while idling are thus implicitly regulated by Community type-approval legislation. However, it should be pointed out that the emissions while idling in a traffic queue are strongly influenced by the degree of congestion encountered (stop-and-go traffic) and can thus not be answered in a general manner. The Commission does not have detailed information on this topic at present.

There are many transport models that use emission factors for establishing the quantity of emissions emitted by motor vehicles at different constant road speeds and these emission factors are always in the process of update as new vehicles meeting more stringent emission standards enter the market and the data on which the emission factors are based is improved.

Taking typical emission factor data and concentrating only on diesel vehicles and the main regulated pollutants of oxides of nitrogen (NOx) and particulates, a modern diesel engined passenger car may emit 40 % less NOx and 20 % less particulate travelling at a steady 50 kilometre per hour (km/h) than at a steady 120 km/h.

A diesel engined light commercial vehicle may emit 43 % less NOx and 70 % less particulate travelling at a steady 50 km/h than at a steady 120 km/h.

A diesel engine articulated heavy-duty vehicle may emit 3 % less NOx and 12 % more particulate travelling at a steady 50 km/h than at a steady 100 km/h.

Of course, these figures can all be influenced by ambient conditions such as temperature, humidity and road gradient.

(1) Directive 98/69/EC of the Parliament and of the Council of 13 October 1998 relating to measures to be taken against air pollution by emissions from motor vehicles and amending Council Directive 70/220/EEC, OJ L 350, 28.12.1998, specific table p. 15.

(2) Directive 1999/96/EC of the Parliament and of the Council of 13 December 1999 on the approximation of the laws of the Member States relating to measures to be taken against the emission of gaseous and particulate pollutants from compression ignition engines for use in vehicles, and the emission of gaseous pollutants from positive ignition engines fuelled with natural gas or liquefied petroleum gas for use in vehicles and amending Council Directive 88/77/EEC, OJ L 44, 16.2.2000, specific table p. 22.