Scientist Describes Air Pollution by Engines

Press, Volume XCVI, Issue 28370, 31 August 1957, Page 6

Scientist Describes Air Pollution by Engines

The extent to which engine exhaust gases pollute the atmosphere was described by Miss J. B. Ross, of the Dominion Laboratory, Wellington, to yesterday’s session in the conference of the New Zealand Institute of Chemistry. The day's programme was held at Canterbury Agricultural College, Lincoln.

Carbon monoxide in the exhaust gas from a petrol engine was greater than in the exhaust of diesel engines; but diesel engines were greater polluters of air because of the smoke and tarry substances they emitted, she said.

“The public has become much more conscious in the last 10 years or so of the pollution of our atmosphere,” said Miss Ross. "Although the exhaust gases from road vehicles are not as great as the pollution from industrial furnaces and domestic chimneys, they are emitted into the air at a low

level and can be inhaled before much dispersal has taken place. "Under all operating conditions, the carbon monoxide in diesel exhaust fumes is considerably less than that in the exhaust gases from petrol engines. This is because the air present is always in excess of that required to burn a diesel' fuel completely,” said Miss Ross. The heavier fuel oil contained more naphthenes and unsaturated cyclic compounds which, on “cracking,” gave tar-like products and depositions of carbon, she said. “In practice, good maintenance and operation give a considerable reduction in this type of pollution. “Oxides of nitrogen, the product of high-combustion temperatures are, with high loads, greater with petrol engines. Their removal is not successful with plain water baths, but it is hoped that further work will find a suitable absorbent” >