Summary

In the previous exercises, we have seen the sort of questions you need to ask to enable you to develop a sampling strategy to assess worker exposures to airborne contaminants. We have seen that the main things you need to do are:

• Carry out an initial evaluation of the process: to decide whether sampling is actually necessary and to gather information to help develop your sampling strategy.
• Decide whether to take personal or static samples: personal sampling is normally preferred, but there are some situations where static sampling might be more appropriate.
• Decide whether to undertake worst-case or representative sampling: it is often sensible to look at the worst case situation, but representative sampling might be needed, particularly if we want to look at the full spread of exposures.
• Decide on how long to sample for: you can sample for the full-shift or part of the shift. Alternatively you can take grab samples or perform continuous sampling. Whether you take long or short term samples will largely depend on the type of occupational exposure limit assigned to the substance.
• Choose your method: it is important that you use a correct method for the contaminants you want to measure.
• Determine the number of samples you should take: this is probably the most difficult decision to make! It will be partly governed by whether you want "worst- case" or "representative" measurements. It will also be governed by the resources available to you.
• Carefully interpret your results: you need to make sure that there is an appropriate exposure limit and take into account how long the workers are exposed to the substance.

If you do all this, you should have obtained meaningful results which will help you to make an assessment of the risks to the health of the workers due to inhalation of the substances they are exposed to while they carry out their work.

Air sampling can be a useful way of assessing worker exposures. However, it has one very important limitation.

It can only tell you about what the worker is likely to be inhaling. However, in some situations, particularly where skin contact with the substances can occur, substances can enter the body by skin absorption or accidental ingestion. In this case, air sampling alone will not give you enough information to make a full assessment of the risk.