Bioaerosol exposure assessment in the workplace: the past, present and recent advances.
Eduard-W; Heederik-D; Duchaine-C; Green-BJ
J Environ Monit 2012 Feb; 14(2):334-339
Louis Pasteur described the first measurements of airborne microorganisms in 1861. A century later, the inhalation of spores from thermophilic microorganisms was shown to induce attacks of farmers' lung in patients with this disease, while endotoxins originating from Gramnegative bacteria were identified as causal agents for byssinosis in cotton workers. Further epidemiological and toxicological studies have demonstrated inflammatory, respiratory, and pathogenic effects following exposure to bioaerosols. Exposure assessment is often confounded by the diversity of bioaerosol agents in the environment. Microorganisms represent a highly diverse group that may vary in toxicity. Fungi and bacteria are mainly quantified as broad groups using a variety of viable and nonviable assessment methods. Endotoxins and beta(1 --> 3)-glucans are mainly measured by their activity in the Limulus amebocyte lysate assay, enzymes by immuno-chemical methods and mycotoxins by liquid chromatography-mass spectrometry. Few health-based occupational exposure limits (OELs) are available for risk assessment. For endotoxins, a health-based OEL of 90 endotoxin units m-3 has been proposed in the Netherlands. A criteria document for fungal spores recently proposed a lowest observed effect level of 100,000 spores m-3 for non-pathogenic and non-mycotoxin producing species based on inflammatory respiratory effects. Recent developments in bioaerosol assessment were presented at the Organic Dust Tromsl Symposium including molecular biological methods for infectious agents and organisms that are difficult to cultivate; studies of submicronic and hyphal fragments from fungi; the effect of biodiversity of microorganisms in asthma studies; and new/improved measurement methods for fungal antigens, enzymes and allergens. Although exposure assessment of bioaerosol agents is complex and limited by the availability of methods and criteria, the field is rapidly evolving. Environmental impact: This paper describes current methods for the measurement of exposure to bioaerosols at the workplace, and occupational exposure limits that are available for risk assessment. The assessment of health risks from bioaerosol exposure is complex due to diversity of the agents. Few regulatory occupational exposure limits have been adopted for bioaerosol agents, but proposed health-based exposure limits for endotoxins and fungal spores can be used. New developments are shortly reviewed, including molecular biological methods; studies of submicronic and hyphal fragments from fungi; the effect of biodiversity of microorganisms on asthma; and new/improved measurement methods for fungal antigens, enzymes and allergens. These methodological advancements are expected to aid in exposure and risk assessments of bioaerosol exposure in the future.
Aerosols; Exposure-assessment; Biological-monitoring; Microorganisms; Airborne-particles; Bacteria; Fungi; Endotoxins; Bioassays; Toxic-materials; Mycotoxins; Infectious-diseases; Analytical-chemistry; Analytical-instruments; Analytical-processes; Analytical-methods; Antigens; Allergens; Enzymes; Measurement-equipment; Exposure-limits; Risk-analysis
Wijnand Eduard, National Institute of Occupational Health, PO Box 8149, Oslo, Norway
Agriculture, Forestry and Fishing; Services
Journal of Environmental Monitoring