Chch smoke exceeds W.H.O. safety levels

Press, 5 July 1985, Page 5

Chch smoke exceeds W.H.O. safety levels

Smoke levels in Christchurch have exceeded the World Health Organisation’s recommended safety level of 125 micrograms per cubic metre six times this winter. The highest reading was on the evening of June 27, when the smoke reading was 341 micrograms in the inner suburbs, 247 micrograms in the city streets, and 162 micrograms in the outer suburbs and industrial areas. Sulphur dioxide readings have not exceeded the safety level so far this winter. These figures were given in the figure summary for June compiled by the Health Department’s air pollution section. The readings represented .more of a nuisance value rather than a safety hazard, said the regional air pollution control officer, Mr Don

Pullen. "Anything white you wear gets dirty quicker,” he said. “There is a large safety factor built into the World Health Organisation’s safety levels to give protection to all members of a society, including the very young and the very old, as well as those with respiratory problems,” said Mr Pullen. “They are really setting a level for no effect,” he said. “The next level where some effect is expected is 250 micrograms, over several days.” Weather also plays a big part in yielding higher air pollution readings. “If the weather is very calm and still, we can expect to get exceptionally high readings,” said Mr Pullen. “If the weather is calm for several days on end, we could possibly get readings

as high as 341 in some areas.” The winters of 1983 and 1984 were influenced by such weather conditions, said Mr Pullen. Between 1981 and 1982, fuel consumption figures remained constant, but the pollution levels varied. “This is probably a reflection of the weather patterns,” said Mr Pullen. Smoke levels last winter exceeded the W.H.O. safety levels 10 times, and in 1983 they were exceeded six times. A decrease in emissions and pollutants to the atmosphere was evident since 1982, but these had not been low enough to sustain a low reading, said Mr Pullen. Prohibiting the consumption of coal with a sulphur content of more than 1 per cent might have had a "slight effect” on the inner suburbs, he said.

Peak pollution hours were between 6 p.m. and midnight during the winter. The main pollutants in Christchurch were from domestic, industrial, and commercial users, and from transportation. “Transportation is the biggest source each year of air pollution,” said Mr Pullen. Carbon monoxide and nitrogen oxide levels are at their highest about 8.30 a.m. and between 4.30 p.m. and 5.30 p.m. The Air Pollution Office hopes to acquire a nephelometer, an instrument which gives a reading re-, lated to what one can see.' “The nephelometer will' give a better pattern showing when the peaks are occurring,” said Mr Pullen. The office will have to wait until the expenditure for the instrument is approved by the Government.