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Exposure Monitoring - The What, How & Why

Updated: Apr 6, 2021

What is exposure monitoring?

Exposure monitoring is a way of measuring the extent of occupational health hazards, that come in the following forms: biologic, chemical, and physical.


Biological hazards are caused by a biological substances that poses a threat to the health of living organisms, most notably human! This can include samples of microorganisms, viruses, or toxins (from a biological source), but can also include substances harmful to other animals. An example of biological hazard that everyone should be aware of is Covid-19!


A chemical hazard is a type of occupational hazard caused by exposure to chemicals in the workplace. Exposure to chemicals in the workplace can cause acute or long-term detrimental health effects. There are many types of hazardous chemicals, including carcinogens, mutagens and sensitizers. These hazards can cause physical and/or health risks. Depending on chemical, the hazards involved may be varied.


Physical hazards can cause harm with or without contact and include noise, vibration, radiation, and the thermal environment.

How do we carry out exposure monitoring?

There are many ways to monitor exposures, and the method selected typically depends on the agent’s route into the body, or the effect they cause. Some of the more common methods used are:

  • Personal air sampling or static (fixed-point) background sampling – this form of exposure monitoring is of particular use when most, if not all the exposure occurs via inhalation. Common forms of air sampling include wood dust monitoring, welding fume monitoring, and respirable crystalline silica (RCS) dust monitoring.

  • Wipe sampling of the skin – this form of exposure monitoring is useful when the exposure occurs via skin absorption.

  • Biological monitoring and biological effect monitoring – this form of monitoring can be particularly useful as it considers all routes of exposure (inhalation, ingestion, skin contact and injection). The downside of this type of monitoring is it can be much more invasive and typically require blood or urine samples from those exposed.

  • Noise measurement – noise is a physical agent which can be measured by using a sound level meter (SLM) and noise dosimetry badges. These instruments work by measuring the sound pressure levels. Although the typical unit used to measure pressure is Pascals, noise measurements are more commonly given in decibels (dB), which is due to the huge range of values that occur in any survey. The use of dB avoids problem is it a logarithmic scale.

  • Vibration measurement – vibration is also a physical agent which is separated into hand-arm vibration and whole-body vibration. Measurement is conducted using an accelerometer at point of contact to the vibration source.

Why do I need to carry out exposure monitoring?

There is in fact a legal requirement to carry out exposure monitoring in certain circumstances. You may carry out exposure monitoring to:

  • Determine compliance with an exposure limit and/or demonstrate they are not exceeded.

  • Determine compliance with legislation.

  • Determine the effectiveness of the control measures currently in place or validate the effectiveness of a newly implemented control measure.

  • Collect and collate quantitative information to use as part of an informed risk assessment.

  • Reappraise following changes made to the plant and/or process.

  • Identify if health surveillance is required.

  • Determine the suitability of Personal Protective Equipment (PPE) selection.

When don’t I need to carry out exposure monitoring?

Although monitoring exposure is usually fundamental to ensuring that workers are safe in their workplace, it is not always appropriate. You may opt not to carry out exposure monitoring if:

  • A suitable sampling, analysis or quantification technique does not exist and cannot be devised.

  • An alternative evaluation method can be used to demonstrate effective control e.g., smoke tubes, air velocity measurements, Tyndall illumination (dust lamp) checks etc.

What if I need help to carry out exposure monitoring?

At Blue Turtle Ltd, we provide a range of services to help businesses of all types manage their workplace health hazards. Our experienced consultants can provide practical advice on how to achieve adequate control through process changes, improvements or adopting/changing work practices to reduce the risk as low as reasonably practicable.

Whatever your Occupational Hygiene needs are, Blue Turtle Ltd is here to help your business protect your workforce and help you meet your legal obligations.

Give us a call today to discuss your needs or if you prefer, complete the online form with a brief outline of your business needs and/or concerns.

Blue Turtle - The missing cog in your business health!

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