Vol. 509 No. 1
252 Mr. Dukes asked the Minister for the Environment and Local Government the effect on atmospheric quality of hydrogen sulphide from emissions from unleaded petrol; and if hydrogen sulphide is regarded as a greenhouse gas. [19839/99]
Hydrogen sulphide (H2S) is a toxic malodorous gas listed on the US environmental protection agency's list of extremely hazardous substances; it is not regarded as a greenhouse gas. Emissions of H2S are a side effect of the operation of catalytic convertors in vehicles when purging sulphur depositions from the catalyst. However, the amounts emitted from vehicles are minute. Consequently, emission factors for vehicles are not set in EU legislation nor has an EU ambient air quality standard been set or proposed for H2S.
The EU auto oil programme requires more stringent environmental specifications for fuels with up to 70 per cent less sulphur in petrol and 30 per cent in diesel; these measures will facilitate further reductions of H2S emissions. I am satisfied, to the extent of the knowledge available to me, that this gas has no discernible effect on Irish ambient air quality.
