In recent years, bioaerosols (the term given to airborne microorganisms and their products) have become an important occupational health issue in the areas of agriculture, biotechnology, and nonindustrial indoor environments. Much of the concern regarding exposure to bioaerosols has focused on the ability of certain microorganisms to elicit inappropriate immunological responses in susceptible individuals. Adverse health effects to microorganisms are ultimately determined by the immunological state of the exposed individual, the affecting agent (e.g., fungi, bacteria, viruses, cell wall constituents, protozoans, and metabolic products such as mycotoxins), the airborne concentration, and the associated disease outcome (infection versus a sensitization reaction). A comprehensive understanding of these determinants and their interactions is necessary to help resolve occupant exposure risk. Microorganisms (including fungi and bacteria) are normal inhabitants of the environment. The saprophytic varieties (those utilizing non-living organic matter as a food source) inhabit soil, vegetation, water, or any reservoir that can provide an ample supply of nutrients. Under the appropriate conditions (optimum temperature and pH, sufficient moisture, and available nutrients) saprophytic microorganism populations can be amplified. Through various mechanisms, these microorganisms can then be disseminated as individual cells or in association with soil, dust, or water particles. In the outdoor environment, the level of bioaerosols will vary according to the geographic location, climatic conditions, and surrounding activity. In a well-maintained indoor environment, where there is no unusual source of microorganisms, their level may vary somewhat as a function of HVAC system filtration, the overall cleanliness of the HVAC system, and the number and activity level of occupants. Typically, the indoor levels of bioaerosols are expected to be below the outdoor levels with a consistently similar ranking among the individual microorganisms.
Microorganisms; Microbiology; Respiratory-infections; Respiratory-irritants; Respiratory-system-disorders; Pulmonary-system-disorders; Pulmonary-disorders; Allergies; Ventilation-equipment; Ventilation-systems; Aerosols; Aerosol-particles; Immunologic-disorders; Fungal-diseases; Fungal-infections; Fungi; Case-studies; Statistical-analysis; Analytical-models; Analytical-methods; Occupational-diseases; Occupational-exposure; Occupational-health; Occupational-respiratory-disease; Worker-health; Workplace-monitoring; Workplace-studies; Work-analysis