DEPARTMENTS
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ENGINEERING CONTROLS
Ventilation and Managing Indoor-Air Bioaerosol Hazards
Allergies and Asthma Are Disease Syndromes Often Associated with Indoor Bioaerosol Exposures
BY D. JEFF BURTON
Studies by NIOSH, EPA, and others have confirmed that indoor air quality problems in employee occupancies (like offices, commercial buildings, and schools) regularly involve the presence in air of bioaerosols—also known as microbes, microbiological agents, microorganisms, biogenic particles, airborne organisms, organic dusts, and viable pathogenic aerosols, all of which are particles of biological origins.

Typical bioaerosols found in indoor air include fungal and mold spores; bacteria and viruses suspended in tiny water particles; cat, dog, and rodent dander; insect parts; tree, grass, and weed pollens; human shed skin particles; and other organic dusts. Airborne bioaerosols usually range in size from 0.1 to 100 micrometers in diameter.

Symptoms of microbiological activity indoors often include allergic reactions like sinus trouble, runny nose, eye irritation, and other irritations of the upper respiratory tract. The primary cause of allergies is immunological sensitization to aerosolized mold spores, insect parts, animal dander, and pollen. Asthma, a more serious respiratory disease characterized by shortness of breath and wheezing, can also be triggered by indoor bioaerosols. According to the Asthma and Allergy Foundation of America, bioaerosols cause allergies for up to ten percent of the population and asthma for about 3-4 percent. Ventilation systems are always involved, both as a source of problems and their solutions, so the occupational health and safety professional must be aware of how the ventilation system operates in order to provide bioaerosol control.
D. JEFF BURTON is an IH engineer with broad experience in ventilation used for emission and exposure control. He is the author of many books and training courses and is current chair of the ANSI Z9.2 and Z9.10 subcommittees. His full biography can be found online. He can be reached via email.