WRITTEN QUESTION E-2403/98

by Doeke Eisma (ELDR) to the Commission

(27 July 1998)

Subject: Catalyst, laughing gas and the greenhouse effect

Is the Commission aware of the information recently published by the US environment agency (EPA) to the effect that, although the new generation of three-way catalysts are more effective than old catalysts in rendering such gases as nitrogen oxides and carbon monoxide harmless, they produce more laughing gas (N2O)?

Is the Commission also aware that with the same new three-way catalysts the emission of laughing gas varies somewhat as a function of car use and the temperature of the catalyst, making reliable estimates of laughing gas emissions difficult?

What does the Commission intend to do about this measuring problem in connection with the monitoring of laughing gas (proposal COM(98) 0108(1)) and any standards relating to catalysts (Auto Oil II) that may be adopted in the future?

How will the Commission address the emission of laughing gas in this context in view of the increasing mobility of transport and the fact that laughing gas is three hundred times more effective in blocking heat than CO2?

Answer given by Mr Bangemann on behalf of the Commission

(22 October 1998)

The Environmental protection agency (EPA) report(2) cited by the Honourable Member has recently been updated by a further report(3) of the United States environment protection agency office of mobile sources (EPA-OMS). The EPA-OMS report critically reviews the conclusions of the EPA report and describes the results of specific tests at the EPA-OMS facility to measure the emission of nitrous oxide (N2O) from a range of new and older United States motor vehicles. This measurement programme continues and shows there to be no problem measuring N2O emissions from vehicles.

The EPA-OMS study suggests that fuel sulphur content has a significant effect on N2O emissions (which is confirmed by European data). The lower the fuel sulphur content the lower the emissions of N2O. Also, vehicles fitted with more recent emission control aftertreatment, for example the latest three-way catalyst technology, demonstrated lower emissions of N2O than older vehicle types fitted with less advanced catalysts. Vehicle mileage was seen to have no significant effect on N2O emissions. The Commission has regular contact meetings with colleagues in the EPA-OMS and will be discussing this study at its next meeting in mid-October 1998.

Conciliation between the Parliament and the Council at the end of June 1998 achieved an agreement on the Auto-Oil package of measures relating to future motor vehicle emission levels and fuel quality. That agreement invited the Commission to bring forward proposals after the end of 1999 which, among other things, will consider "the contribution of other measures, including those relating to fuels and vehicles, to the attainment of longer term Community objectives on air quality, taking into account technological developments and the results of new air pollution related research ...". In response to this mandate, the Commission will take into account any new substantiated research that may demonstrate a need to consider, in the future, setting limits for certain emissions from motor vehicles which are presently not regulated.

The Community has an ambitious strategy to reduce CO2 emissions from cars. Measures to improve significantly car fuel consumption efficiencies which would entail low sulphur fuels as well as actions aimed at reducing passenger miles and promoting intermodal shifts in the transport sector will also reduce emissions of N2O.

(1) OJ C 120, 18.4.1998, p. 22.

(2) "Draft Inventory of US Greenhouse Gas Emissions and Sinks 1990-1996", March 1998.

(3) "Emissions of Nitrous Oxide from Highway Mobile Sources", EPA420 - R-98-009, August 1998.