HSE Impacts of VOCs

Introduction
Volatile organic compounds (VOCs) are substances with low boiling points that evaporate from solids or liquids used in industrial processes, for example, formaldehyde evaporating from paint, or benzene from fuel[1].  Workplace exposure limits (WEL) are the legal limits set on the amount of substances that can be present in workplace air. Hazardous substances must be below the relevant workplace exposure limit.

What is a VOC?
Volatile organic compounds (VOCs) are a wide range of naturally and synthetically occurring chemicals that are found almost everywhere on earth. They are described as volatile because they evaporate at standard temperature and pressure, releasing molecules into the atmosphere. VOCs are also extremely useful as they form the building blocks of many synthetic materials (plastics, rubbers, glues, paints, etc.), and are used to create pharmaceuticals and are a great fuel for transport and heating.

Health and safety issues
As VOCs exist as a gas at room temperature the main exposure route is through breathing. Exposure to harmful VOCs can happen at home, outdoors, or in the workplace.

Some sources of VOCs in a domestic and light industrial setting include building materials, furniture, carpets, heating and cooking systems, stored solvents, and cleaning products. Generally, VOCs are released slowly from these sources giving off low levels and would not cause a problem.

However, modern buildings have low air exchange rates which can cause concentrations to easily rise to harmful levels. This has been emphasised during the Covid-19 pandemic where good air flow and air exchange are an easy way to ensure any virus in the air is removed from the space and helps reduce the risk from aerosol transmission, when someone breathes in small particles (aerosols) in the air after a person with the virus has been in the same enclosed area. VOCs are now widely recognized as a major contributor to sick building syndrome which in turn compromises Indoor Air Quality (IAQ).

Research has shown that people spend approximately 90% of their time indoors. Consequently, for many individuals, the risks to health may be greater due to air pollution exposure from indoors rather than outside.

In medium and heavy industries, there are a wider source of VOCs and higher concentrations can also exist. Here, VOCs pose additional threats as some VOC vapours are heavier than air and may displace oxygen in confined spaces posing an asphyxiation risk to workers.

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