Deadly pollutant

Sir,
The EEC will shortly announce new exhaust emissions limits. The mandatory fitting of catalytic converter systems is probable.

This situation displays the capacity of politicians and environmentalists to be beguiled by remorseless lobbying, for converter systems produce their own particular and deadly pollutant: sulphuric acid. Oxidising catalysts in the converter cause the sulphur in petrol to be oxidised beyond the sulphur dioxide (SO3) which is a normal product of combustion, to SO, and thence to sulphuric acids. When vast numbers of vehicles are fitted with these devices, the result is acid rain.

Catalytic converters are wasteful of fuel, expensive to install and, more importantly, costly to maintain. The Environmental Protection Agency estimates that at any one time up to 20% of all installations in the USA are wholly or partly inoperative. Converters do not function at full efficiency at the time of greatest need, the warm-up period, when, due to mixture enrichment, emissions are at their highest.

All the normal pollutants may be brought under effective control by fundamental improvements to combustion efficiency, i.e. the lean-burn engine.

GW West, Southampton, Hampshire