ABSTRACT
Within the last 10 years a comprehensive understanding evolved regarding the nature and importance of bio-aerosol exposures and their relationship to allergic lung disease. A major factor contributing to the dearth of this knowledge prior to this time was the inability to characterize the toxic and immunologic potency of these aerosols. Progress and advancement in particle collection methods and immunochemistry have allowed characterization of complex mixtures of pathogenic and proteinaceous material. Although light microscopy facilitated morphologic identification of particulates (molds, pollen, fungi) and yielded some semi-quantitative data, there was a void in our understanding of aerosol potency and intensity until immunochemical methods were developed and applied in aero-biological studies. These studies included particle sizing, and distribution and quantification of the concentration of asthmagenic bio-aerosols. It became evident that even bio-aerosols comprising relatively large identifiable particulates (greater than 10 mm; pollens, mold, and fungi) contained smaller particle fractions which also conferred even more antigenic activity to the respiratory mucosa. These early studies elucidated the importance of immunochemical measurement of natural and man-made bio-aerosols. The general principles of industrial and environmental hygiene also apply in all respects to allergens, just as they do to any airborne toxic agents. Differences in application of these general principles to occupational asthma (OA) arise from the requirement for specialized sampling and assay techniques and from the fact that often not all workers are affected by the illness. Workers who develop lung hypersensitivity to airborne antigens develop symptoms and other signs often after exposure to very low concentrations of the agent that have no or little effect on other workers. Identification of offending agents and clinical evaluation of patients are considered in Chapters 7 and 16-24. This chapter summarizes the methods of air sampling and quantitative immunoassay, the principles for devising means of reducing the concentration of
allergens in the air, and the procedures for follow-up monitoring to assure that measures undertaken to control exposure continue to be effective.
