[Importance and measurement of sulfates in floating dust]

In recent toxicological and epidemiological studies observable health effects have been associated with exposure to respirable particles. Atmospheric sulfate aerosols, rather than SO2 alone, seems to be representing a major public health problem. In an interdisciplinary project on particulate matter, atmospheric sulfates were also measured in the ambient air of Zurich. Sampling was performed with High Volume Sampler and for the analysis of sulfates the so called photometric copper complex method was used. Random samples taken at 3 stations during 2 sampling periods showed sulfate concentrations in the range of 5 to 23 micrograms/m3, the overall average being 16 micrograms/m3. In the light of present knowledge and the concentrations measured, the problem of sulfates cannot be ignored.