WHO Indoor Air Quality Standards Explained

What is the World Health Organisation (WHO)?

By Stephen Glass, Technical Sales Manager, February 2022

As more evidence emerges about the long-term health effects of poor indoor air quality on our lives, it is worth paying close attention to the World Health Organisation’s (WHO) comprehensive indoor air quality standards and to consider its recommendations for properties, both now and in the future.

The World Health Organisation was first established in 1948. Its mission, both then and almost 75 years later, is “the attainment by all peoples of the highest possible level of health.” As a specialised agency of the United Nations (UN), the WHO monitors public health risks promotes better human health and wellbeing and coordinates responses to health emergencies. It has also played a crucial role in the global battle against the coronavirus pandemic over the last year.

The WHO’s remit is broad, making recommendations to promote and ensure the health and wellness of citizens around the world. WHO/Europe has, for many years, recognised the dangers of poor indoor air quality particularly, the impact of unseen and undetected pollutants within our homes which are generated by simple everyday tasks that we perform day in and day out. It outlines the impact these can have on our overall wellness and has published WHO guidelines for indoor air quality.

What are the WHO standards for indoor air quality?

As a society, we increasingly spend more time living and working, indoors. With this comes a need to be mindful of the air that we’re breathing each day. Activities that we perform as part of family life, from cooking with gas to spraying cleaning products, can linger in the air for long periods of time if left unattended and can have serious health implications.

The WHO guidelines for indoor air quality address sizeable public health issues, noting that 1.5 million deaths each year are associated with the indoor combustion of solid fuels. It makes clear recommendations to address these.

WHO Guidelines for Dampness and Mould

A key element of poor indoor air quality is microbial pollution, the forming of mould indoors in poorly ventilated areas. WHO’s review states that dampness and mould, which emerges through inadequate ventilation, contributes towards the increased risk of developing respiratory symptoms, allergies and asthma, as well as damaging the immune system. Its comprehensive guidelines are intended for worldwide use, to protect public health and to support the achievement of optimal indoor air quality.

WHO provides the following dampness and mould health guidelines to building developers, architects, landlords and homeowners:

• Persistent dampness and mould on interior surfaces should be avoided or minimised. The presence of condensation on surfaces is a key indicator of dampness.
• Internal moisture levels should be managed through the proper control of temperatures and ventilation to avoid excess humidity, condensation on surfaces and excess moisture in materials. Stagnant air zones should be avoided within properties, with ventilation effectively distributed throughout internal spaces.
• Building owners are responsible for providing and maintaining a healthy living environment or workplace, free of excess mould and moisture. This includes ensuring proper building construction and ongoing maintenance. WHO states that the property’s occupants are responsible for managing the use of water, heating, ventilation and appliances in a way that avoids the emergence of dampness and mould growth.

WHO Guidelines for Selected Pollutants

The WHO states that free access to air and water of acceptable quality is a fundamental human right. It also recognises that, as people spend an increasing amount of time indoors, potential exposure to harmful air pollutants rises. Its guidelines for selected pollutants are specifically targeted at the public health professionals involved in preventing health risks of environmental exposures, and at the specialists and authorities involved in the design and use of buildings, indoor materials, and products.

The report examines a number of pollutants that are known to be harmful to overall wellbeing, including Carbon Monoxide, Nitrogen Dioxide, Naphthalene, Formaldehyde and Radon. It is the latter, Radon Gas, that has become particularly concerning in recent years. This dangerous gas - which has now been linked to lung cancer - can seep into properties through windows, cracks, drains, groundwater and even the soil, entering from the bottom-up. Awareness of Radon Gas has grown in recent years after a Public Health England report mapped Radon levels around the UK, finding that some parts of the country are currently at risk of being exposed to high levels of the gas.

The WHO’s guidelines state that acceptable indoor air quality can be achieved through:

• Source control and pollutant dispersion
• The application of low-emission materials and products
• The proper selection of the devices and fuels used for combustion indoors
• The venting of products to the outdoor air and ventilation control.

WHO Standards for Household Fuel Consumption

The way in which energy is used within home environments can have a detrimental impact on indoor air quality. The WHO has found that, globally, by far the most important direct risk to health is household air pollution caused by the incomplete combustion of fuel in low-efficiency stoves and lamps used for cooking, space heating and lighting. This is a very big issue, with around 3 billion of the world’s poorest people still relying on the burning of solid fuels for cooking and heating.

The WHO’s household fuel consumption guidelines state that maximising the cleanliness of combustion in household energy devices is critical for both unvented and vented sources. The guidelines recognise that modern households have multiple energy needs. Therefore, compensatory actions should be taken in response to the impact that daily cooking, heating, and lighting can have on indoor air quality. It recognises that ventilation - through windows, chimneys and eaves - plays a key part in addressing the total dose of pollutants found in the air and the linked health effects.

WHO air quality guidelines for particulate matter

The issue of airborne particulate matter (PM) - the mixture of solid particles and liquid particles found in the air - affects more people than any other pollutant.

Particles are emitted from all manner of sources, from unpaved roads to fields and fires, with most particles forming in the atmosphere as a result of reactions to other chemicals. Some of these particles can get deep into your lungs, with the potential to lead to sizeable health implications.

The WHO’s comprehensive air quality guidelines for particulate matter aim to promote a gradual shift from high to lower concentrations, providing targets for concentrations of PM10 and PM2.5. Its guidelines highlight the lowest levels at which total, cardiopulmonary and lung cancer mortality have been shown to increase, by addressing long-term exposure to particulate matter.

Do you need to adhere to WHO standards for indoor air quality?

The WHO’s standards for indoor air quality are a proven and trusted framework for ventilation best practice, offering a robust, scientifically-backed rationale for ensuring that fresh, clean air can flow freely into our living environments.

Close adherence to WHO’s standards should be a clear goal for anyone involved in building or maintaining a property. Its guidelines are extensively researched to provide and promote the protection of public health and to demonstrate the very real dangers of overlooking indoor air quality.

For more information about ventilation best practices for commercial properties, including office ventilation systems, visit our commercial heat recovery systems page.

Pay close attention to your indoor air quality

As leading specialists in ventilation solutions for more than 50 years, Nuaire provides a range of proven strategies to improve indoor air quality. From Positive Input Ventilation, the most energy-efficient and effective method of preventing condensation and cleaning up indoor air in existing homes, to Nuaire’s Dri-master-Eco Positive Input Ventilation (PIV), tried-and-trusted by new-build developers, social housing providers and private landlords alike. Committed to constant innovation, Nuaire remains focused on delivering fresh, healthy and safe indoor environments for all.