North London Partners in health and care

What does indoor air quality mean and how can we improve it

Tom Parkes
Senior Air Quality Officer, Camden Council

We are more aware than ever about the health impacts of exposure to outdoor air pollution.

We have a fairly comprehensive understanding of the key sources of pollution in the outdoor environment, how these are transported in the air, and how they can affect our bodies.

It is now well-established that short- and long-term exposure to pollution can cause and worsen respiratory and cardiovascular illnesses, increase the risk of stroke, and even present a cancer risk.

For this reason we have targets which dictate an ‘acceptable’ level of pollution in the air based upon our understanding of the health impacts: in 2018, Camden adopted the World Health Organization’s objectives for particulates (PM), setting ambitious targets for reducing the health impact associated with this pollutant.

Camden’s Clean Air Action Plan 2019-2022 sets out our pathway to meeting World Health Organization objectives for air quality, adopting a new community- and public health-focused approach to build on the work we have undertaken already. Through our collective action to raise awareness, the introduction of the Ultra Low Emission Zone (ULEZ), and our own projects such as Health School Streets, we are seeing improvements in air quality in some of the most polluted parts of Camden and London.

What is more difficult to understand, however, is the impact that chemicals and environmental conditions inside buildings can have on our health, and how we can reduce this. We refer to this as ‘indoor air quality’.

What is indoor air quality?

We spend up to 90% of our time indoors – 22 hours each day – in our homes, offices and schools. What many of us do not realise is that many of the pollutants which impact our health on the street and in the playground will also be present inside buildings.
Whilst some of this indoor pollution may be derived from familiar external sources such as road transport and construction sites, there are also several important sources of pollution inside our buildings.

These sources include our heating systems, kitchen appliances, furnishings, decorations, cleaning products and even personal care products such as deodorants and body sprays.

How can we improve indoor air quality?

The science on indoor air quality is still in its early stages, and there is much to learn about the complex relationships between different chemicals, their health impacts, and the most effective ways to reduce pollution in the indoor environment.
As a first step it is crucial to raise awareness about this issue, and to share what we already know about the small steps that we can all take to reduce emissions and exposure.

For this reason, we are working to develop advisory ‘toolkits’ with recommendations for improving air quality inside our schools, businesses and our homes. We will be working with schools to support them in better understanding their own indoor air quality by recognising key sources of indoor pollution, undertaking air quality measurements and suggested changes to improve indoor air quality.

For now, here are some of the small but potentially significant changes which can improve indoor air quality:

  • Avoid smoking in the home – cigarette smoke is a common source of indoor pollution
  • Avoid burning any solid fuels inside buildings – don’t use wood-burning stoves or fireplaces
  • Ensure your cooking area is well ventilated – especially if you have a gas hob
  • Prevent the build-up of moisture and humidity – keep the space well-ventilated
  • Reduce the use of chemical cleaning products – and switch natural products where possible
  • Avoid the build-up of dust on carpets and surfaces – keep spaces tidy and dust frequently
  • Avoid using artificial indoor air fresheners or paraffin candles and burners
  • Be mindful that soft furnishings are sources of pollutants such as formaldehyde – buy second hand or keep spaces ventilated when introducing new items, and…
  • Choose solid floors over carpets where possible – carpets can also be major sources of chemicals and can also trap dust

By making some of these changes we can help to reduce our exposure to pollution indoors and improve health and wellbeing in these environments.

As a final point, it is important to recognise that this is not a new issue – indoor air pollution will have been a health risk since humans first created habitable structures – but the more we learn about the problem as it currently exists, the healthier our indoor spaces will be.

To find out more about our work to improve air quality in Camden please visit our website,, or contact us directly at