Why is Indoor Air Quality more important than ever?

22.04.2021 3 min read

The COVID-19 pandemic has accelerated a shift to people spending more and more time indoors. It is now estimated that the average Brit spends up to 22 hours a day indoors, equating to around 90% of their time, including in schools/educational institutions, at home, or in the workplace. Consequently, ensuring that the air we breathe in these indoor settings is not negatively impacting our health is becoming increasingly important.

Air can carry harmful pollutants and as it enters our homes and places of work, it can bring these pollutants in from the outside. Our indoor environments can also contain sources of air pollution including cookers, boilers, cleaning products, and biological contaminants, such as bacteria, mould, and dust mites. Inadequate ventilation and poor air exchange rates can cause indoor pollutants from these sources to build up to potentially dangerous levels that can pose a threat to human health.

Many people work in environments where they are exposed to a variety of substances such as chemicals, fumes, dust and vapors, volatile organic compounds, particulate matter, bacteria, or nitrogen oxides all of which could be classified as ‘hazardous to health’. In order to determine how to protect workers from these substances, the Control of Substances Hazardous to Health (COSHH) Regulations impose duties on employers to monitor exposure to hazardous substances.

Occupants of buildings with poor indoor air quality report a wide range of health problems including headaches, poor concentration, fatigue, shortness of breath, and nausea. When these symptoms are thought to be caused by indoor air quality, they are sometimes described as Sick Building Syndrome (SBS), Building-Related Illness (BRI) or Multiple Chemical Sensitivities (MCS).

The draft guidance was been produced by the Institute of Air Quality Management (IAQM) in June 2021 to assist its members in the assessment of indoor air quality  (IAQ). The guidance is applicable to new and existing buildings of all types including residential, commercial, retail, education, healthcare (except in specialist settings such as operating theatres) and community facilities (e.g. care homes). This guidance is explicitly not intended to override any legally defined protections of workers such as those related to the Control of Substances Hazardous to Health (COSHH) and EH40 Workplace Exposure Limits (WELs) (HSE, 2020).

For pollution to cause an effect there must be a source, a pathway and a receptor. If they all are present, an IAQ assessment is required which includes 4 stages:

  • Stage 1: Scoping Study (to define the level of assessment required)
  • Stage 2: Assessment
  1. Simple assessment (Source Pathway Receptor): This approach assesses the risk caused by the pollutant which is likely to be present where people spend their time. The risk is assessed by combining the magnitude of the potential for harm from the ingress of ambient air and indoor sources of pollution with the potential exposure.
  2. Detailed assessment (Monitoring &/or modelling): This is required when there is a possibility of medium or high risk as per the simple assessment.
  • Stage 3: Mitigation/improvement opportunities
  • Stage 4: Reporting

Monitoring may be required:

  • following a simple indoor air quality assessment in accordance with IAQM guidance
  • as part of a COSHH risk assessment to help select the right controls
  • where substances present a serious health risk
  • to check or to confirm that exposure limits are not exceeded and check the suitability of existing controls
  • to identify any need for health surveillance
  • when an inspector has issued an enforcement notice that requires you to monitor exposure

We have a team of specialists in Air Quality team who have a wealth of experience and expertise to undertake indoor air quality assessments and monitoring. We will measure and assess environmental factors, such as temperature, relative humidity airflow, inhalable particles, build-up of carbon monoxide, volatile organic compounds and airborne allergens or pathogens.

We endeavour to make a positive impact and create a healthy environment by identifying the root causes of indoor air quality problems and neutralising the risks. For further information, please get in touch:


Key Contacts

Dr Xiangyu Sheng Director - Air Quality, Climate & Carbon