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  • fungi: aerobiology, dispersion of spores,
  • fungi: spore, aerosol



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    		Essay:

    Bioaerosols

    "Bioaerosols are defined by the ACGIH as airborne particles, large molecules or volatile compounds that are living, contain living organisms or were released from living organisms. The size of a bioaerosol particle may vary from 100 micons to 0.01 micron. The behaviour of bioaerosols is governed by the principles of gravitation, electromagnetism, turbulence and diffusion." This link was broken when checked on Dec. 2006Online source

    "Most microorganisms rely upon air as an important means for dispersal (movement from one location to another); therefore, it is not surprising to find that each cubic meter of air, whether it's indoors or outdoors, may contain thousands or even millions of microorganisms! This collection of aerosolized biological particles is referred to as a Bioaerosol. The size of these particles varies between a fraction of a micrometer (¦Ìm) to approximately 30 ¦Ìm. Particles larger than 30 ¦Ìm can also become airborne; however, they have a tendency to settle to a surface much faster than smaller, lighter cells. The fate of any particle, regardless of size, is ultimately dependent on a number of variables. The most important of these factors include seasonal variances, geography, time of day, moisture levels, wind speed, wind direction (from source), air humidity, and temperature". -- This link was checked on Dec. 2006Online source

    "The Bioaerosol Detection Problem

    Bioaerosols are ubiquitous in the earth's tropospheric boundary layer, although they typically occur in small concentrations.1¡ã3 They have both natural and anthropogenic sources. Bioaerosols are found in the workplace,4 in residential houses,5 in medical facilities,6;7 in manufacturing operations in which metalworking ¡ãuids are used,8 in animal-hair processing facilities,9 in dairy facilities,10 or other animal houses,11 in sites of sludge application,12 in recycling or composting plants,13 in sanitary land?lls,14 and in sewage plants.15 Unlike most common atmospheric aerosols, airborne microorganisms can cause disease, allergies and res piratory problems. Bioaerosols are feared as potential biowarfare and terrorist agents.16¡ã19 Improved methods for measuring aerosols, particularly bioaerosols, are needed. Presently, methods that measure aerosol size distributions in real time provide almost no information about particle types and are not able to identify speci?c microorganisms. Efforts to develop ?eldable instruments for detection and identi?cation of airborne biological particles have accelera ted during the last several years.

    The ideal instrument for detecting bioaerosols would be compact and portable, have a fast response, and provide speci?c identi?cation. Current e?orts are concentrating on two complementary types of apparatus: (1) a bioaerosol detector that could operate continuously without consumables and give a real-time indication of the presence of bioaerosol particles in certain broad classes, and (2) an identi?er of speci?c microorganisms, based on biological recognition molecules, which (it now appears) would be slower, require consumables and a logistics trail, and would require collection of the particles.21¡ã26 These two types might be combined into a single instrument, with the bioaerosol detector serving as a warning device in dicating when to turn on the identi?er for speci?c microorganisms.

    A bioaerosol detector that provides real-time detection, even without speci?c identi?cation of bacteria or protein toxins in particles, would be useful for studying the prevalence and dispersion of bioaerosols in the atmospheric boundary layer, in the workplace, and in medical and agricultural facilities, etc. A potential limitation of instruments which identify speci?c microorganisms in a reasonable time (e.g., 30 minutes), is that such instruments at present require the prior generation of speci?c recognition molecules for each microbe, allergen, or toxin of interest. A bioaerosol detector that does not identify might be particularly useful in cases where new, or unexpected types of bioaerosol occur. The primary quasi-real-time bioaerosol detection methods that require no reagents and are not capable of identifying speci?c microorganisms fall into two categories: (1) those that exploit the intrinsic ¡ãuorescence (total27¡ã30 or spectrally dispersed31¡ã37) of biological molecules, and (2) those that perform mass spectrometry of ions created by laser ablation,38 laser desorption,39¡ã42 or pyrolysis43¡ã46 of particles."-- This link was checked on Dec. 2006Online source

    tidbits:

    This link was checked on Dec. 2006Aerobiological Engineering (www.arche.psu.edu/iec/abe/)

    This link was checked on Dec. 2006microbial_contamination_sampli


    Related References:


    CRDBER, at CBS, BCEE, ENCS, Concordia,