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Bioaerosols: the Focus of Workplace Research

New approaches for the measurement and risk assessment of airborne biological agents

It is difficult to assess the risks posed by activities which involve high rates of exposure to complex mixtures of airborne biological agents. There is a lack of appropriate measurement and evaluation methods. The BAuA is therefore conducting intensive research into bioaerosols.

Micro-organisms are everywhere to be found. This means that our skin, our digestive systems and our airways come into contact with them every day. In comparison with normal exposure which is generally harmless, many employees experience additional exposure to airborne micro-organisms at their places of work, however. This is primarily the case in two large areas:

  • areas of work in which employees carry out activities with materials or living organisms which represent the natural living environment of the micro-organisms (soil, water, plants, as well as animals and people)
  • areas of work which are colonised by micro-organisms during the production process, whether this considered desirable (food refinement, for example), or undesirable (cooling lubricants, for example)

In this context, the concentrations of airborne micro-organisms can reach 10,000 times the normal levels.

Depending on the type of biological agent, the level of exposure, its duration and the individual's state of health, such exposure can put the health of employees at risk. The hazards range from infections through to toxic or sensitising effects.

Warning symbol for the hazards posed by bioaerosols with additional elements for viruses, bacteria and the human respiratory system Drafting of a "Bioaerosols warning" symbol, © BAuA

Biological agents in the risk assessment

On the basis of the possible risks, the Occupational Safety Act and the Accident Prevention Regulation "Principles of Prevention" of the DGUV oblige all employers to assess the potential hazards posed to the employee according to the activities that they carry out. Depending on this assessment, employers must also specify protective measures and document the results of their evaluations. This procedure, which is known as a "risk assessment", is the key element in ensuring safety at the workplace. It provides the basis for the systematic and successful health and safety management (GDA, 2011).

As a general rule, the employer must obtain information such as the identity, infection potential and sensitising and toxic characteristics of the existing biological agents which pose a potential hazard to employees. Information on the following must also be provided (BioStoffV):

  • the exposure scenarios, including the type, level and duration of the exposure
  • the associated transfer possibilities
  • the occupational diseases which are known to be associated with the exposure

The path to a status quo for bioaerosols

In the overwhelming majority of the stated sectors, insufficient information is available to enable the completion of the risk assessments as required. There are differing reasons for the gaps in knowledge. There is no measurement obligation for the determination of the exposure levels. Among others, this means that standardised methods of collection and measurement are only available for a limited number of parameters. For many parameters, the results from the scientific literature are not fit for comparison, or can only be transferred to other areas of work to a limited extent.

For many workplaces, the biological agents that a bioaerosol contains remain unclear. This is because the culture-based methods which are currently used are unable to capture all of the micro-organisms. In addition to the identification of the biological agents, their quantification, and therefore assessing exposure to them, is problematical. Also, little is known about the sensitising and toxic characteristics of the biological agents. Causal relationships between individual parameters and the occurrence of specific illnesses cannot, therefore, be derived, or only to a limited extent.

To close the existing gaps in knowledge, as a departmental research institute, the BAuA maintains laboratories in which its employees work on developing new methods of measurement and instruments of assessment, and are presently conducting scientific field research into bioaerosols at the workplace.