§ Mr. Ieuan Wyn Jones
To ask the Secretary of State for Transport if his Department has conducted a comparative study of the pollutant gases and particulate matter released from(a) cars run on leaded petrol, (b) cars run on unleaded petrol, (c) cars fitted with catalytic converters run on unleaded patrol and (d) diesel engined cars, each in terms of weight carbon monoxide, carbon dioxide, nitrous oxide and sulphur dioxide per mile.
§ Mr. Atkins
[holding answer 15 December 1989]: The Department has not conducted a comparative study of the type suggested, but the following points may be of 13W assistance. There should be no difference in emissions, other than of lead, between non-catalyst vehicles running on leaded or unleaded petrol. Sulphur emissions are directly related to the sulphur content of fuel, which is regulated in the United Kingdom to 0.3 per cent. by weight for diesel and 0.2 per cent. by weight for petrol. Particulate emissions from petrol engines, provided they are not worn out and burning lubricating oil, are negligible compared with particulate emissions from diesel engines.
Co (g/mile) HC + NOx (g/mile) Particulate (g/miles) EC Directive 83/351 (the current non catalyst standard) 23–24 7.6–11.1 No standard until October 1990 EC Directive 89/458 (the future standard to be applied from 1992) 7.6 2.0 0.44 (diesels only)
The standards set by directive 89/458 will be revised when the emission directives are consolidated in the near future. The consolidation will include a revision of the drive cycle used in the test. At present it is 2.58 miles long and simulates urban driving. The revised cycle will he 6.8 miles long and include some high-speed driving. It is likely that a reduction of about 27 per cent. in the particulate limit will also be included in the consolidation.