Workplace and Indoor Air Quality Guidance

DustScanAQ follows best practice guidance in all assessments and reports. Below is an overview of the key legislation, standards, and workplace exposure guidance that apply to air quality and occupational exposure in the UK.

Statutory Instruments (secondary legislation)

Control of Substances Hazardous to Health (COSHH) Regulations (2002)

In Great Britain, exposure to airborne substances or pollutants in the workplace is regulated under the Health and Safety Executive (HSE) Control of Substances Hazardous to Health (COSHH) Regulations.

Regulation 6(1) states that employers “should carry out a suitable and sufficient assessment of the risks to the health of employees and any other person who may be affected by work, if they are exposed to substances hazardous to health.” Regulation 10 further clarifies that monitoring is required “when measurement is needed to ensure a Workplace Exposure Limit (WEL) or any self-imposed working standard is not exceeded.”

There are legally binding Workplace Exposure Limits (WELs) for around 500 substances, as listed in HSE EH40/2005: Workplace Exposure Limits. These include limits for total inhalable and respirable dust, when sampling is undertaken in accordance with the methods described in MDHS 14/4: General Methods for Sampling and Gravimetric Analysis of Respirable, Thoracic and Inhalable Aerosols.

It is important to note that asbestos and lead exposure have separate occupational exposure guidelines; the Control of Asbestos Regulations (CAR) and the Control of Lead at Work Regulations (CLAW) respectively. These regulations include an Occupational Exposure Limit (OEL) for lead and an asbestos control limit.

Exposure limits generally relate to personal monitoring. Although COSHH applies to all workplaces, WELs are not universally applicable. They may not be suitable for certain groups, such as pregnant employees, and are not designed to assess prolonged or non-occupational exposure.

The Building Regulations (2010)

The UK Government’s Ministry of Housing, Communities and Local Government sets ventilation and air quality standards under the Approved Document F1: Means of Ventilation. This statutory guidance forms part of the Building Regulations in England and outlines the requirements for maintaining adequate indoor air quality in workplaces, particularly office environments.

Appendix B of the document provides performance-based ventilation guidance values for several indoor air pollutants; including carbon monoxide (CO), nitrogen dioxide (NO₂), formaldehyde, total volatile organic compounds (TVOC) and ozone (O₃); based largely on World Health Organisation (WHO) recommendations.

It is important to note that these guidance values serve as performance criteria for assessing building ventilation, not as direct occupant exposure assessment thresholds.

Indoor Air Quality Guidelines

UK Government Building Bulletin 101 (BB101) (2018)

For schools and educational buildings, indoor air quality standards are defined within the UK Government Education & Skills Funding Agency’s Building Bulletin 101 (BB101). This document sets out ventilation and air quality guidelines, including maximum carbon dioxide (CO₂) levels in teaching and learning spaces. Much of the guidance is based on WHO indoor air quality standards, which are recommended for use in schools to ensure healthy learning environments.

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WHO Air Quality Guidelines (2021)

The World Health Organisation (WHO) Air Quality Guidelines provide evidence-based recommendations for reducing the health impacts of air pollution. These guidelines are founded on the latest scientific research into the health effects of air pollutants.

Originally published in 1987 (for Europe) and updated in 2000 and 2005, the WHO’s guidelines were reviewed again in 2021 to update interim targets and recommended air quality levels for key pollutants.

In 2010, the WHO also published guidance on indoor air quality, focusing on pollutants such as benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide (NO₂), PAHs, radon, trichloroethylene, and tetrachloroethylene. These pollutants were selected because they are commonly found indoors, hazardous to health, and often present at concentrations of concern.

The guidelines provide a scientific foundation for legal standards used by public health professionals, environmental consultants, and regulatory bodies involved in the design and management of buildings. Some of these have since been incorporated into UK Building Regulations.

WHO guideline values apply to both indoor and outdoor air exposure, and their latest 2021 updates supersede the earlier 2010 indoor air quality guidelines for certain pollutants such as CO and NO₂.

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Other Recent Indoor Air Quality Guidance

Several UK organisations have produced additional indoor air quality guidelines relevant to workplaces, public buildings, and indoor environments:

Public Health England (now UK Health Security Agency): Indoor Air Quality Guidelines (2019)
DEFRA Air Quality Expert Group: Indoor Air Quality (2022)
CIBSE KS17: Indoor Air Quality and Ventilation (2011)
CIBSE Guide A: Environmental Design (2015)
IAQM (Institute of Air Quality Management): Indoor Air Quality Guidance: Assessment, Monitoring, Modelling and Mitigation (2021)

Together, these documents support improved air quality monitoring in the workplace and provide practical direction on managing exposure and compliance.

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Oliver Puddle

(BSc, CSci, MIEnvSc, MIAQM, AFOH)
Technical Director

Discuss Your Requirements with Our Technical Director

If you would like to discuss any aspect of the guidance above, or how these workplace exposure limits and indoor air quality regulations apply to your organisation, we would be happy to arrange an initial consultation to understand your exact requirements.

Please call us on +44 (0)1608 810110 or email Oliver using the email button below.