Air pollution

Press, 2 April 1980, Page 24

Air pollution

Sir, — The Clean Air Society does not base its conclusions on wild surmise or momentary whim but on material collated by the university’s chemical engineering department and the local city health office with annual pollution figures from the Health Department’s air pollution monitoring unit. On the calculated smoke emissions for three winter months in 1976, for instance, the percentage of domestic smoke was 75 per cent of the total; motor vehicles only 7 per cent. Smoke is now increasing in the suburbs. D. Johnston and I would undoubtedly agree that smoking is the grossest form of air pollution. — Yours, etc., JANET R. HOLM. March 30, 1980.

Sir, — Would D. Johnson (March 30) state the precise source of his statistics and give figures for coal consumption over definite periods? This society fully agrees with the comments and findings of D.S.I.R. Report No. 55 insofar as it reported on domestic fires.The facts about open fires have been known for at least 130 years and were probably even known to Ben Franklin in the eighteenth century. Simple observation from the Port Hills during winter afternoons confirms that, domestic chimneys create most of the smoke. In general terms the open fire does not provide the conditions to burn coal completely. It does not allow sufficient air to reach and become intimately mixed

with the volatile matter as it is distilled from the coal. Also, excess air is drawn over the combustion zone to the chimney which chills down the combustive mixture below the temperature requirements for satisfactory smokeless combustion. — Yours, etc., P. V. NEARY, President, New Zealand Clean Air Society. ’ ' ; March 30, 1980.