[Corpuscular pollutants: the problem of particles and fibers (optic microscopy)]

The "Clinica del Lavoro" had already begun work on dust pollution in the working environment in the mid-1930's but was only able to study the problem more in depth at the beginning of the 1950's when the Industrial Hygiene Laboratory was established under the fortunate direction of Professor Nicola Zurlo. The first research studies in that period were aimed at the correct choice of the most suitable sampling equipment and analytical methods for assessment of the extent of such types of pollution. The results achieved in these initial studies, the experience acquired in the field and further, more detailed research enabled Professor Zurlo to develop and perfect new types of sampling instruments that were more appropriate to the goals it was desired to achieve and these instruments are still widely used to-day. The paper also considers the evolution of analytical methods using the optical microscope for determination of the concentration of particles and fibres, most of which were developed and perfected in our Laboratory, up to the present time. It is stressed that phase contrast microscopy is still indispensable for dust analysis and still offers ample scope for research in the field of artificial fibres that have recently been put on the market, even though the electron microscope is now the only acceptable solution for research in living environments.