Indoor air quality

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Article Published 15 Apr 2013 Last modified 11 May 2021
4 min read
Photo: © Jose AS Reyes | Shutterstock
Many of us might spend up to 90 % of our day indoors — at home, work or school. The quality of the air we breathe indoors also has a direct impact on our health. What determines indoor air quality? Is there any difference between outdoor and indoor air pollutants? How can we improve indoor air quality?

It may come as a surprise to many of us that the air in an urban street with average traffic might actually be cleaner than the air in your living room. Recent studies indicate that some harmful air pollutants can exist in higher concentrations in indoor spaces than outdoors. In the past, indoor air pollution received significantly less attention than outdoor air pollution, especially outdoor air pollution from industrial and transport emissions. However, in recent years the threats posed by exposure to indoor air pollution have become more apparent.

Imagine a newly painted house, decorated with new furniture… Or a workplace filled with a heavy smell of cleaning products… The quality of air in our homes, work places or other public spaces varies considerably, depending on the material used to build it, to clean it, and the purpose of the room, as well as the way we use and ventilate it.

Poor air quality indoors can be especially harmful to vulnerable groups such as children, the elderly, and those with cardiovascular and chronic respiratory diseases such as asthma.

Some of the main indoor air pollutants include radon (a radioactive gas formed in the soil), tobacco smoke, gases or particles from burning fuels, chemicals, and allergens. Carbon monoxide, nitrogen dioxides, particles, and volatile organic compounds can be found both outdoors and indoors.

Policy measures can help

Some indoor air pollutants and their health impacts are better known and receive more public attention than others. Smoking bans in public spaces is one of them.

In many countries, smoking bans in various public places were quite controversial before relevant legislation was introduced. For example, within days of the entry into force of the smoking ban in Spain in January 2006, there was a growing movement to assert what many considered their right to smoke in indoor public places. But the ban has also led to greater public awareness. In the days following its entry into force, 25 000 Spaniards per day sought medical advice on how to quit smoking.

Much has changed in public perception when it comes to smoking in public places and on public transport. Many airlines started to ban smoking on short-haul flights in the 1980s, followed by long-haul ones in the 1990s. It is now unthinkable in Europe to allow non‑smokers to be exposed to second-hand smoke on public transport.

Today many countries, including all the EEA countries, have some legislation to limit or ban indoor smoking in public places. After a series of non-binding resolutions and recommendations, the European Union also adopted in 2009 a resolution calling on EU Member States to enact and implement laws to fully protect their citizens from exposure to environmental tobacco smoke.

Smoking bans appear to have improved indoor air quality. Environmental tobacco smoke pollutants are declining in public places. In the Republic of Ireland, for example, measurements of air pollutants in public places in Dublin before and after the introduction of a smoking ban showed decreases of up to 88 % for some air pollutants found in environmental tobacco smoke.

As in the case of outdoor pollutants, the impacts of indoor air pollutants are not limited to our health only. They also come with high economic costs. Exposure to environmental tobacco smoke in EU workplaces alone is estimated at over EUR 1.3 billion in direct medical costs, and over EUR 1.1 billion in indirect costs linked to productivity losses in 2008.

We spend a large part of our time indoors - in our homes, workplaces, schools or shops. Certain air pollutants can exist in high concentrations in indoor spaces and can trigger health problems.

Indoor pollution is much more than tobacco smoke

Smoking is not the only source of indoor air pollution. According to Erik Lebret from the National Institute for Public Health and the Environment (RIVM) in the Netherlands, ‘Air pollution does not stop at our doorsteps. Most outdoor pollutants penetrate into our homes, where we spend most of our time. The quality of indoor air is affected by many other factors, including cooking, wood stoves, burning candles or incense, the use of consumer products like waxes and polishes for cleaning surfaces, building materials like formaldehyde in plywood, and flame retardants in many materials. Then there is also radon coming from soils and building materials.’

European countries are trying to tackle some of these sources of indoor air pollution. According to Lebret, ‘we are trying to substitute more toxic substances with less toxic substances or to find processes that reduce emissions, as in the case of formaldehyde emissions from plywood. Another example can be seen with the reduction of certain radon-emitting materials used in wall construction. These materials were used in the past but their use has since been restricted.’

Passing laws is not the only way to improve the quality of the air we breathe; we can all take steps to control and reduce airborne particles and chemicals in indoor spaces.

Small actions such as ventilating enclosed spaces can help improve the quality of the air around us. But some of our well-intended actions might actually have adverse effects. Lebret suggests: ‘We should ventilate, but we should not over ventilate as this is a substantial loss of energy. It leads to more heating and use of fossil fuels, and consequently means more air pollution. We should think of it as making more sensible use of our resources in general.’

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