Document Yjy1gRKb0LXydVKxnwbOB36KO

CHAPTER XII The Pulmonary Dust Diseases* O. A. SANDER, M.D.t I. Introduction The industrial hygienist and the industrial physician are concerned with dust ' [because of its almost constant dispersion in air, where it may be inhaled and in I lome instances cause disease. This suspension of finely divided particles in the air fciay not ordinarily attract attention in rural areas but the smokiness of large cities jV-'Js immediately apparent. Clean country air may contain as much as 0.2 mg. dust s&flper cubic meter of air, whereas the average amount in city air during the winter imonths is approximately 0.5 mg. per cubic meter of air.1 Thus, the cloud of dust "fthat arises from a stonecutter's chisel is an excessive amount superimposed on that reawhich is present in the already dust-laden air. IrradflitiOn to 'tfie medical problems,' the le'garentangleinents which may relyolve around dustiness are often of sufficient complexity that months of careful gJstudy are required to determine or fix responsibilities. In cities where general in^fdustrial smoke contamination is a perennial problem, individual firms may be ^selected each year to bear the brunt of civic ire, and each year certain luckless '^SjKcorporations are forced to defend themselves in civil suits that are based almost 'r'|entirely upon claims having no factual evidence for support. Medical-legal "situations may be even more complex than the nonmedical problems and are com plicated by numerous intangible factors. Not only does the exact nature of the 'disease, and its relation to dust require proof, but the actual source of exposure .must be determined so that a nondusty industry will not be held responsible |i^dust''di8'ea'se'th'at' may Have"resulted''fr6m exposure'm'any~yeafs' pnbr"t"o~th"e onslt of the disease. This chapter is written as an attempt f,o bring together facts necessary for a . general understanding of dust and dust diseases. The presentation in't'lie'first por tion is somewhat general so that the contents can be readily grcRped'-hy phyRicmns * Revision of Chapter 15, "Dust and Its Role in the Causation of Occupational Disease," by Edward E. Dart, M.D., in first edition. t Section on lung physiology and function written by R. P. Jahn, M.D., Milwaukee, Wis. 1J. M. DallaValle, Micromeritics: The Technology oj Fine Particles. Pitman, New York, 1943.