Methods of measuring sulfur dioxide, dustfall and suspended matter in city air, and their use in the study of air pollution in Italy.

This paper presents a comparative survey of the methods and apparatus used in Italy, particularly in Genoa, for measuring the three main components of city air pollution-sulfur dioxide, dustfall and suspended matter.The most frequently employed devices for sampling sulfur dioxide are the lead-peroxide and volumetric apparatuses, as developed by the British Department of Scientific and Industrial Research. For the collection of dustfall, the British standard deposit gauge is widely used; in Genoa, a simple, low-cost type of dustfall collector has been tried in combination with that gauge, and good results have been obtained. The measurement of suspended matter is effected by the thermal precipitator, electrostatic precipitator and konimeters of different types, in addition to the classic method of filtration through various media. In Genoa, suspended matter is monitored by automatic filter-paper samplers and directional samplers. The use of membrane filters for counting dust particles has proved particularly satisfactory.All these techniques are described in detail, and their results are subjected to statistical analysis.