Sir: Steve Chandler (letter, 29 October) appears to be unaware that the introduction of automotive catalytic converters, whilst allowing reductions in most pollutants, was in fact responsible for an increase of approximately 5 per cent in carbon dioxide emissions. This was due to a necessary decrease in the air/fuel ratio to reduce levels of oxides of nitrogen produced by the combustion process.
Making cars more fuel-efficient is the only way to reduce vehicular carbon dioxide emissions. My 1946 MG not only passes comfortably the emission standards set for the last cars built without catalytic converters, but also achieves fuel consumption figures beyond the reach of many cars built today.
Heathfield, East Sussex