Bøger af Walter Kikuth

Important among the various sources of emission are domestic heating and motor vehicles. Incomplete combustion causes most emissiün. Macro-climatic and micrü-climatic conditions are highly significant in the spread and density üf air pollutiün. Although ünly unpleasant smell or soiling air pollutiün have caused offen ce, we must recognize and examine the main harmful gaseous and powdery ingredients, particularly thüse with lasting harmful effect. Thus, of interest amüng powdery emissions are only the suspended particles « 5 p), because only they can penetrate the lungs. Sedimentation methods are therefore nüt suited to infürm us ün dust aero­ soles injurious to health. The müst important emissions are cancerogenic substances such as 3,4-benzpyren. Under special conditiüns, animal experi­ ments shüw that these substances are able to cause bronchial tumours. The increase in lung cancer appears tü be assüciated with high air püllution in cities; the müst frequently and increasingly proved gaseous emissions are S02, CO and N0 . 2 Müre impürtant than the individual components is the examinatiün of the combinatiün of various gaseous and püwdery air pollutiüns. The catastrophes in London, Donora and in the Maas valley, and special conditions in Los Angeles, are significant examples üf the importance üf air hygiene. Towards the maintenance of clean air, filters can be mounted in chimneys, although filter efficiency drops appreciably with a grain size üf < 5 p.