Bioaerosol

from Wikipedia, the free encyclopedia

Airborne particles of biological origin are referred to as bioaerosol . These are a natural component of the ambient air and can occur in increased concentrations as a result of human activities.

nature

In the standardization , all accumulations of particles ( aerosol ) in the airspace , to which fungi , bacteria , viruses or pollen as well as their cell wall components and metabolic products (e.g. mycotoxins ) adhere, are referred to as bioaerosol. Accordingly, airborne dusts to which components of biological origin adhere are also bioaerosols. In a broader sense, all parts of biological origin, such as skin flakes or fiber parts, are counted among the bioaerosol particles. The majority of bioaerosol particles are complex in terms of shape, size and components.

Particles in a bioaerosol usually have aerodynamic diameters in the size range from 0.01 µm to 100 µm. The larger suspended particles include pollen with diameters in the range from 10 µm to 100 µm, while viruses usually move in a size range from 0.02 µm to 0.4 µm. Airborne spores with a diameter of 2 µm to 15 µm are between these extremes.

Occurrence

Bioaerosols are ubiquitous . Air does not serve microorganisms as a habitat, but only for locomotion. In indoor spaces, unless there is moisture damage or contaminated air conditioning, humans, their pets and indoor plants are the main sources of bioaerosols. Important anthropogenic bioaerosol sources are waste treatment plants , wastewater treatment plants, animal husbandry plants and evaporative cooling plants.

An increased bioaerosol concentration can usually be detected in the vicinity of waste treatment plants, especially for bio-waste. For example, molds , especially Aspergillus fumigatus , are dominant in bio-waste composting plants.

Conidia carriers from Aspergillus fumigatus

In the intensive livestock farming often occur Staphylococcaceae on. Coxiella burnetii is to be expected in sheep and cattle farming, and Chlamydophila psittaci in poultry farming .

The source of bioaerosols can also be the evaporative cooling systems used in many industrial processes to dissipate excess heat - for example small systems in data centers, for food cooling , but also large cooling towers in power plants. As water trickles into air, particles are washed out of the air, which water-borne microorganisms can serve as a source of food. The temperatures prevailing in the circulating water of an evaporative cooling system are in the optimum range for the multiplication of microorganisms. The most common pathogens in these cases are Legionella pneumophila and Pseudomonas aeruginosa .

meaning

Bioaerosols can lead to respiratory diseases and exacerbations of existing diseases (e.g. allergies , bronchial asthma ). As early as 1700, Bernardino Ramazzini described diseases caused by bioaerosols in his paper De morbis artificum . To perform endotoxins that in the cell membrane of most gram-negative bacteria and cyanobacteria are contained, adverse health effects of such jobs that are exposed to an increased concentration of these microorganisms. The penetration of microorganisms into humans can also take place via the gastrointestinal tract, the skin or through injuries. The health-impairing effects of bioaerosols are not limited to living organisms and their metabolic products. Dead microorganisms or their fragments can also cause allergies.

Mitigation options

One way to prevent the spread of bioaerosols is to enclose the springs. It was found that the bioaerosol concentration in the lee of enclosed composting plants was already in the order of magnitude of the background concentration after 200 meters , while in open plants this was not the case even after 500 meters.

Biologically acting exhaust gas cleaning systems, such as. B. biofilters , bioaerosols can be significantly reduced. The secondary emissions of microorganisms emerging from the exhaust gas cleaning system are significantly lower than the separated microorganisms. In animal husbandry systems, it was found that the use of biofilters in exhaust air treatment can minimize bacteria and endotoxins. The use of a combination bio- washer / bio-filter behind a bio-waste treatment plant also led to a reduction in bioaerosols.

Evaporative cooling systems are to be designed in such a way that, among other things , the system can be completely emptied, cleaned and disinfected even after the installation of fillers or heat exchangers . Avoid standing water. The discharge of droplets should be minimized by installing droplet separators .

Metrological recording

Microscopic image of a bioaerosol isolated in a building

The appearance of bioaerosols is often associated with the appearance of odors. However, a comparable spreading behavior of dust, odors and bioaerosols could not be determined, so that bioaerosols have to be recorded separately in immission monitoring. Only the additional burden is of interest. Background concentrations, which are subject to seasonal fluctuations, must also be determined. While only slight seasonal fluctuations can be assumed for bacteria, there are significant changes in the concentration of mold in the course of the year.

The measurand for the quantification of bioaerosols is their concentration. It is given in colony-forming units per cubic meter (CFU / m 3 ).

Molds

To detect mold, a defined amount of air is sucked through a suspended matter filter . This are gelatin filters used with polycarbonate filter underneath it. The samples obtained in this way are then cultivated and counted after a standardized period without optical aids.

Impactors are used to check indoor air for mold spores . If the size distributions of the spores are to be recorded, cascade impactors can be used.

bacteria

Air to be checked for bacteria is passed through a collection solution so that the particles carried along in the air are separated out in the solution. The bacteria caught in the solution based on casein and soy peptone are then cultivated under standardized conditions and counted after a defined period of time.

Viruses

The air carries viruses and other pathogens. Because viruses are smaller than other particles of biological origin, they have the potential to travel further distances. In one simulation, a virus and a fungal spore were released simultaneously from the top of a building; the spore only flew 150 meters while the virus traveled many horizontal kilometers.

In one study, aerosols (particle size <5 μm) containing SARS-CoV-1 or SARS-CoV-2 were generated using an atomizer and fed into a Goldberg barrel to create an aerosolized environment. The inoculum gave cycle thresholds between 20 and 22, similar to those observed with samples from the upper and lower respiratory tract of humans. SARS-CoV-2 remained viable for 3 hours in aerosols, with a decrease in the infection titre measured similar to SARS-CoV-1. The mean half-lives of both viruses in aerosols were 1.1 to 1.2 hours. The results suggest that the transmission of both viruses by aerosols is plausible, since they can remain infectious for hours in suspended aerosols. Virus-containing aerosols can be released when you breathe out, but more so when speaking and singing .

Public perception and conclusions

Legionella pneumophila under the scanning electron microscope

Bioaerosols have been the focus of public reporting in recent years at irregular intervals and without being named as a generic term. In 1976, numerous deaths after a veterans meeting due to contaminated air conditioning led to the discovery of legionnaires' disease . 233 diseases with a total of 22 deaths at a flower show in the Netherlands with two contaminated whirlpools exhibited there in 1999 can be traced back to the same pathogen . The legionellosis outbreak in Warstein in 2013 with over a hundred illnesses and several deaths could be traced back to legionella in the evaporative cooling system and sewage treatment plant of a brewery. Already three years earlier there was a legionella outbreak in Ulm due to a contaminated evaporative cooling system.

The establishment of a limit value for bioaerosols proves to be problematic due to the different effects of the individual species on humans. Increased public awareness, however, has led to the publication of ministerial decrees in several federal states (e.g. Lower Saxony and North Rhine-Westphalia) to reduce bioaerosols from animal husbandry facilities. On March 22, 2017, the German Federal Cabinet passed a draft ordinance on evaporative cooling systems .

literature

  • VDI 4250 sheet 1: 2014-08 Bioaerosols and biological agents; Environmental medical assessment of bioaerosol immissions; Effects of microbial air pollution on humans (bioaerosols and biological agents; Risk assessment of source-related ambient air measurements in the scope of environmental health; Effects of bioaerosol pollution on human health). Beuth Verlag, Berlin. ( Table of contents , abstract )
  • Wolfgang Mücke, Christa Lemmen: Bioaerosols and health. Effects of biological substances in the air and practical consequences. ecomed medicine, 2008, ISBN 978-3-609-16371-0

Individual evidence

  1. ↑ a b c DIN EN 13098: 2001-02 workplace atmosphere ; Guidelines for the measurement of microorganisms and endotoxin in air; German version EN 13098: 2000. Beuth Verlag, Berlin. P. 4.
  2. ↑ VDI 4250 sheet 1: 2014-08 Bioaerosols and biological agents; Environmental medical assessment of bioaerosol immissions; Effects of microbial air pollution on humans (bioaerosols and biological agents; Risk assessment of source-related ambient air measurements in the scope of environmental health; Effects of bioaerosol pollution on human health). Beuth Verlag, Berlin. P. 5.
  3. ↑ Wolfgang Mücke, Christa Lemmen: Bioaerosols and health. Effects of biological substances in the air and practical consequences. ecomed Medicine, 2008, ISBN 978-3-609-16371-0 , p. 13.
  4. ↑ Wolfgang Mücke, Christa Lemmen: Bioaerosols and health. Effects of biological substances in the air and practical consequences. ecomed Medicine, 2008, ISBN 978-3-609-16371-0 , p. 14.
  5. ↑ Eckart Schulz: Investigation of the device-dependent collection efficiency and the microscopic detection of airborne pollen. Hazardous substances - keeping the air clean , Volume 61 (2001) 6, pp. 261–265.
  6. ↑ VDI 4255 sheet 1: 2005-10 bioaerosols and biological agents; Emission sources and mitigation measures; Overview (Bioaerosols and biological agents; Sources of emissions and control measures; Overview). Beuth Verlag, Berlin. P. 61.
  7. ↑ a b Volker Kummer, Michael Kühner, Andrea Hausmann: Sources of emissions and measures to reduce bioaerosols in composting. Hazardous substances - keeping the air clean, Volume 61 (2001) 6, pp. 239–244.
  8. ↑ Daniela Schneider, Udo Jäckel, Andrea Gärtner, Frank Diterich: Taxonomic characterization of airborne bacteria of the Staphylococcaceae family in emissions from broiler fattening systems - importance for the risk assessment. Hazardous substances - keeping the air clean, Volume 75 (2015) 6, pp. 340–346.
  9. ↑ VDI 4255 sheet 2: 2009-12 Bioaerosols and biological agents; Sources of emissions and mitigation measures in farm animal husbandry; Overview (Bioaerosols and biological agents; Emission sources and control measures in livestock operations; Overview). Beuth Verlag, Berlin. P. 7.
  10. ↑ RH Ahrens: Legionella are technically controllable . VDI nachrichten No. 48 of November 28, 2014, p. 11.
  11. ↑ VDI 2047 sheet 2: 2015-01 recooling plants; Ensuring the hygienic operation of evaporative cooling systems (VDI cooling tower rules) (Open recooler systems; Securing hygienically sound operation of evaporative cooling systems (VDI Cooling Tower Code of Practice)). Beuth Verlag, Berlin. P. 11.
  12. ↑ VDI 4250 sheet 1: 2014-08 Bioaerosols and biological agents; Environmental medical assessment of bioaerosol immissions; Effects of microbial air pollution on humans (bioaerosols and biological agents; Risk assessment of source-related ambient air measurements in the scope of environmental health; Effects of bioaerosol pollution on human health). Beuth Verlag, Berlin. P. 7.
  13. ^ Philippe Duquenne, Geneviève Marchand, Caroline Duchaine: Measurement of Endotoxins in Bioaerosols at Workplace: A Critical Review of Literature and a Standardization Issue . Annals of Occupational Hygiene , 2012, doi : 10.1093 / annhyg / mes051
  14. ↑ a b Caroline Herr, PM Bittighofer, Jürgen Bünger, Thomas Eikmann, Anna Barbara Fischer, Christel Grüner, Helga Idel, Anja zur Nieden, Urban Palmgren, Hans-Joachim Seidel, Hans-Georg Velcovsky: Effect of microbial aerosols on humans. Hazardous substances - clean air , Volume 59 (1999) 6, pp. 229-239.
  15. ↑ Dirk Heller, Rudolf Rabe: Spread of bioaerosols from composting plants of various types. Hazardous substances - keeping the air clean, Volume 61 (2001) 6, pp. 245-253.
  16. ↑ Torsten Herold, Mirko Schlegelmilch, Bernd Dammann, Jan Streese, Rainer Stegmann, Andreas Hensel: Germ retention in the treatment of intensive rotting air in a bio-washer / bio-filter system. Hazardous substances - keeping the air clean, Volume 61 (2001) 6, pp. 255–260.
  17. ↑ VDI 4255 sheet 2: 2009-12 Bioaerosols and biological agents; Sources of emissions and mitigation measures in farm animal husbandry; Overview (Bioaerosols and biological agents; Emission sources and control measures in livestock operations; Overview). Beuth Verlag, Berlin. P. 21.
  18. ↑ Volker Kummer, Renate Haumacher, Werner Philipp, Reinhard Böhm: Investigations into the separation behavior of exhaust air purification systems with regard to bioaerosols. Hazardous substances - keeping the air clean, Volume 63 (2003) 9, pp. 368–372.
  19. ↑ VDI 2047 sheet 2: 2015-01 recooling plants; Ensuring the hygienic operation of evaporative cooling systems (VDI cooling tower rules) (Open recooler systems; Securing hygienically sound operation of evaporative cooling systems (VDI Cooling Tower Code of Practice)). Beuth Verlag, Berlin. P. 13.
  20. ↑ a b Thomas Eikmann, Susanne Harpel, Caroline Herr: Why are there no limit values ​​for bioaerosols? - A statement from an environmental medicine point of view. In: Commission for keeping the air clean in the VDI and DIN - KRdL standards committee (ed.): Microbial air pollution. KRdL-Schriftenreihe 35, 2005, ISBN 3-931384-53-5 , pp. 221-225.
  21. ↑ Thomas Lung, Irene Tesseraux: Background concentrations of mold in the outside air - parameters for annual mean and variation. Immissionsschutz, Volume 18 (2013) 2, pp. 64–69.
  22. ↑ Irene Tesseraux, Thomas Lung: Background concentrations of total bacteria and other bioaerosol parameters in urban areas. Hazardous substances - keeping the air clean, Volume 74 (2014) 9, pp. 368–376.
  23. ↑ VDI 4251 sheet 2: 2015-08 Recording of airborne microorganisms and viruses in the outside air; Determination of area-specific background concentrations (Measurement of airborne microorganisms and viruses in ambient air; Determination of area-specific background concentrations). Beuth Verlag, Berlin. P. 10.
  24. ↑ Annette Kolk, Rainer Van Gelder, Gerd Schneider, Stefan Gabriel: Microbiological background values ​​in the outside air - evaluation of the BGIA exposure database MEGA. Hazardous substances - keeping the air clean, Volume 69 (2009) 4, pp. 130-136
  25. ↑ VDI 4256 sheet 1: 2010-10 Bioaerosols and biological agents; Determination of process parameters; Counting method based on cultural evidence (bioaerosols and biological agents; determination of performance characteristics; culture-based counting methods). Beuth Verlag, Berlin, p. 13.
  26. ↑ VDI 4252 sheet 2: 2004-06 Recording of airborne microorganisms and viruses in the outside air; Active sampling of bioaerosols; Separation of airborne mold on gelatine / polycarbonate filters (Measurement of airborne microorganisms and viruses in ambient air; Active sampling of bioaerosols; Separation of airborne mold on gelatine / polycarbonate filters). Beuth Verlag, Berlin. P. 7.
  27. ↑ VDI 4253 sheet 2: 2004-06 Recording of airborne microorganisms and viruses in the outside air; Method for the cultural detection of mold concentrations in the air; Indirect method after sampling on gelatine / polycarbonate filters (Measurement of airborne microorganisms and viruses in ambient air; Culture based method for the determination of the concentration of mold in air; Indirect method after sampling with gelatine / polycarbonate filters). Beuth Verlag, Berlin. P. 12.
  28. ↑ DIN ISO 16000-20: 2015-11 Indoor air pollution ; Part 20: Detection and enumeration of mold; Determination of the total number of spores (ISO 16000-20: 2014). Beuth Verlag, Berlin, p. 11.
  29. ↑ DIN ISO 16000-18: 2012-01 Indoor air pollution ; Part 18: detection and enumeration of mold; Sampling by impaction (ISO 16000-18: 2011 + Cor.1: 2011). Beuth Verlag, Berlin, p. 12.
  30. ↑ VDI 4252 sheet 3: 2008-08 Recording of airborne microorganisms and viruses in the outside air; Active sampling of bioaerosols; Separation of airborne bacteria with impingers according to the principle of the critical nozzle (Measurement of airborne microorganisms and viruses in ambient air; Active sampling of bioaerosols; Separation of airborne bacteria with impingers using the principle of critical nozzle). Beuth Verlag, Berlin. P. 5.
  31. ↑ VDI 4253 sheet 3: 2008-08 Recording of airborne microorganisms and viruses in the outside air; Method for the quantitative cultural detection of bacteria in the air; Method after separation in liquids (Measurement of airborne microorganisms and viruses in ambient air; Culture based method for the quantitative determination of bacteria in air; Method after separation in liquids). Beuth Verlag, Berlin. P. 7.
  32. ↑ Andrés Núñez, Guillermo Amo de Paz, Alberto Rastrojo et al .: Monitoring of airborne biological particles in outdoor atmosphere
  33. ↑ Neeltjevan Doremalen, Dylan H.Morris, Myndi G.Holbrook et al .: Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1 The New England Journal of Medicine, May 2020th
  34. ↑ NDR: Now common sense is required Interview with Christian Drosten
  35. ↑ Jianyun Lu, Jieni Gu, Kuibiao Li et al .: COVID-19 Outbreak Associated with Air Conditioning in Restaurant, Guangzhou, China, 2020 Centers for Disease Control and Prevention 2020
  36. ↑ Hendrik Streeck1, Bianca Schulte et al .: Infection fatality rate of SARS-CoV-2 infection in a German community with a super-spreading event, page 12
  37. ↑ Wolfgang Mücke, Christa Lemmen: Bioaerosols and health. Effects of biological substances in the air and practical consequences. ecomed Medicine, 2008, ISBN 978-3-609-16371-0 , p. 157.
  38. ↑ VDI 2047 sheet 2: 2015-01 recooling plants; Ensuring the hygienic operation of evaporative cooling systems (VDI cooling tower rules) (Open recooler systems; Securing hygienically sound operation of evaporative cooling systems (VDI Cooling Tower Code of Practice)). Beuth Verlag, Berlin, p. 3.
  39. ↑ Avoid legionella . In: UmweltMagazin , April / May 2017, p. 47.