What do I need to know about Ozone?

What is ozone?

Ozone (O3) is a triatomic molecule which consists of three oxygen atoms (oxygen consists of two atoms), and is a colourless gas.

Where is it found?

Stratospheric ozone (in the upper atmosphere) is known as the ozone layer and protects our health by shielding us from the sun’s ultraviolet rays. However, at ground level, ozone (tropospheric ozone) is a pollutant with highly toxic effects. It is a hazard to human health, the environment and a wide range of natural and artificial materials.

What is the significance of ground-level ozone?

Ground level ozone can cause eye irritation, headaches, coughing, impaired lung function and eye, nose and throat irritation.  Asthmatics and children are most at risk.

What causes ground-level ozone?

Ground level ozone comes from the reaction of oxides of Nitrogen (NOx) and volatile organic compounds (VOCs). This occurs readily in the presence of sunlight.  It is also a product of reactions between chemicals produced by burning fuels and some of the chemicals found in paints. Ozone can be emitted from older photocopiers and printers in the workplace.  Motor vehicle and industrial emissions are major sources of the pollutants which can be broken down to produce ground-level ozone.

What are the exposure limits?

The Health and Safety Executive guidance note, Occupational Exposure Limits EH40 occupational exposure standard for ozone is 0.20ppm (parts per million) over a 15-minute reference period.

Are the exposure limits likely to be exceeded in an office environment?

Modern offices contain a variety of equipment ranging from photocopiers, faxes and laser printers, which may emit low levels of ozone. However, the levels of ozone which are emitted are usually well below the HSE occupational exposure limit. Most modern photocopiers and laser printers are already fitted with filters, which limit the amount of ozone released into the atmosphere. This ensures that even when equipment is operating in the minimum specified environmental conditions (i.e. the machine is situated in the smallest site location recommended, and with only natural ventilation to the room), it meets all the national and international occupational exposure limits for ozone.

 How can you measure ozone levels?

Levels of ozone can be measured by Assurity Consulting as part of an indoor air quality (IAQ) audit. We have been auditing workplace environments since 1986. During the thousands of tests we have conducted to monitor ozone, on only one or two occasions have we detected levels which were above the HSE occupational exposure limit. More often than not, the levels of ozone in the ambient atmosphere of an office are so low that they cannot even be detected.

How can you limit the amount of ozone in the workplace?

There should be no need to fit additional filters to office equipment in order to reduce ozone levels. There are products on the market, such as vaporizers, which claim to reduce ozone levels. However, Assurity Consulting is not aware of any conclusive evidence to show that these products actually achieve this objective.  Therefore, we do not recommend the use of such items as a means of reducing ozone. If you are concerned about the levels of ozone in your workplace, the following measures could help minimise exposure to ozone:

 

  • Ensure that equipment such as photocopiers, laser printers and faxes are situated in a well-ventilated area.
  • All office equipment should be regularly serviced and maintained to ensure that it is in good working order.

 

This guide is of a general nature; specific advice can be obtained from Assurity Consulting. Assurity Consulting is the UK's leading independent compliance consultancy specialising in workplace health, safety and environmental solutions. We have over 30 years' experience of helping customers of all sizes, from across all sectors, manage their compliance responsibilities, making sure that their organisation is compliant, their employees are safe, their processes are cost-effective and their management team is in control.

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