Taking action to improve indoor air quality
What pollutants are typically found in our indoor air?
Indoor environments can be polluted by:
- Chemical pollutants: volatile organic compounds (VOCs), nitrogen oxide (NOx), carbon monoxide (CO), polycyclic aromatic hydrocarbons (PAHs), phthalates, etc.;
- Organic contaminants: mould, household allergens from dust mites, pets and cockroaches, pollen, and so on;
- Physical pollutants: particles and fibres (asbestos, artificial mineral fibres), etc.
On average, we spend 75% of our time in our home according to the data of the second national housing campaign (CNL2).
Focus on volatile organic compounds
VOCs comprise various chemicals that evaporate easily at room temperature. They are found in:
- paints, varnishes, adhesives, cleaning products and air fresheners,
- some new furniture and building materials,
- and scented candles and incense.
For example, long-term exposure to formaldehyde and benzene can cause irritation, allergies or even cancer. ANSES has developed indoor air quality guidelines (IAQGs) for these substances and has participated in an analysis of VOC emissions from building and decoration products.
Where do these pollutants come from?
These pollutant emissions can have various sources:
- building components: building materials, paint, etc.;
- decoration products and furniture: new furniture, mattresses, upholstery, etc.;
- fuel-burning appliances: boilers, stoves, water heaters, etc.;
- our lifestyle habits: smoking, pets, scented candles, air fresheners, etc.;
- the transfer of outdoor pollution to indoor environments.
What are the health effects?
The quality of the air we breathe can impact our health and well-being, with effects ranging from simple discomfort – olfactory dysfunction, drowsiness, eye and skin irritation – to the onset or worsening of acute or chronic conditions such as respiratory allergies, asthma, cancer, or even disabling or fatal poisoning.
What is the cost of indoor air pollution?
In recent years, several studies have estimated the health impact of indoor air pollution, including the associated economic cost, to help guide public policies and support the implementation of actions. In France, a first exploratory study in which ANSES took part determined that indoor air pollution costs approximately €19 billion per year.
What is ANSES doing about indoor air pollution?
The Agency supports public decision-makers by helping to advance knowledge of the risks associated with air pollution. Its complementary expert appraisal, monitoring and research activities, carried out as part of the National Research Programme for Environmental and Occupational Health, allow it to issue recommendations and acquire scientific data to better protect health. In this context, ANSES has explored various aspects of indoor air pollution through the prism of:
- The pollutants found in air, such as mould in buildings and settled dust;
- emission sources: emissions from building materials, support for the labelling of decoration or upholstery products, essential-oil based sprays and diffusers;
- specific environments: indoor car parks, swimming pools and underground railway areas.
ANSES has also carried out work on more specific topics, such as the:
- characterisation of the transfer of outdoor air pollution to the inside of buildings,
- analysis of air purification techniques,
- use of microsensors to monitor the quality of indoor and outdoor air.
Last but not least, ANSES develops IAQGs. These values are intended to protect the population against any adverse effects that may arise from exposure to a substance – usually a chemical – via air. They are used by the public authorities as a scientific basis for establishing regulatory values for the monitoring of indoor air quality.
But the Agency's work extends far beyond air!
Since 1 January 2024, ANSES and the French Scientific and Technical Centre for Building (CSTB) have been jointly supporting the Indoor Environment Quality Observatory (OQEI), which manages, compiles and analyses data to improve the quality of indoor environments.
Its scope covers all issues affecting the comfort and health of occupants in enclosed environments, whether public or private: air quality, dust, noise, natural and artificial light, temperature and electromagnetic fields. The OQEI works to inform and guide all stakeholders interested in the quality of indoor environments.
This will allow ANSES to:
- strengthen its risk assessment activities relating to pollution in indoor environments, for example by taking account of exposure through the ingestion of indoor dust;
- develop indoor dust guidelines (IDGs) to be used as a basis for interpreting measurement results in terms of health risks associated with the ingestion of dust. In 2026, ANSES published its first IDGs for lead and phthalates.
How can you improve indoor air quality?
Everyone can do their part on a daily basis to improve air quality in indoor environments. Here are some simple ways you can limit indoor pollution:
- Reduce pollution sources: avoid smoking indoors, and limit the use of scented candles, incense and air-freshener sprays;
- open windows for at least 10 to 15 minutes every day, even in winter, to bring in fresh air and clear out pollutants that accumulate in your home, at school or at your workplace;
- limit humidity: air out the bathroom after showering, use the extractor hood in the kitchen, and cover pots while cooking;
- do not block air vents or turn off any ventilation;
- regularly maintain your heating and ventilation systems.
In summary
- The air we breathe indoors is polluted, just like outdoor air;
- Everyone can take some simple steps like regularly opening the windows to improve the quality of the air we breathe indoors;
- Parameters other than air in indoor environments are receiving increasing attention, as reflected in the creation of the OQEI.
