Tainted by a range of pollutants that have the potential to harm our health, indoor air quality has become a pressing issue for vulnerable groups such as children and people with asthma. Eliminating pollutants from our daily lives requires us to think about how we construct buildings and how people live in them. We talked with Dr. Suzanne Déoux, mastermind of a master’s degree focusing on health risks in the built environment (RISEB) in France, founder of the health engineering company Medieco and creator of the Construction Health Challenges Conference, which she started in 2011 to raise awareness and start a conversation about this issue.

We often talk about outdoor air pollution. What about indoor air quality?

Indoor air quality has now become a major public health issue. It is even more important than outdoor air quality, as we spend between 80 and 90% of our lives indoors and therefore have greater exposure to pollutants there. The problem dates back to the oil crisis of the 1970s when, to save energy, people got in the habit of opening the windows less and filling in the holes that helped with air circulation. This “caulking culture,” in combination with the development of new construction and furniture materials and cleaning products with higher pollutant emissions, has undermined indoor air quality, leading to the problems we are seeing today.

What are the main indoor air pollutants today?

Indoor air pollutants can be classified by their source. Outdoor air contributes particulates, nitrogen oxides and benzene. A variety of substances can seep in from the ground if it is contaminated, and the soil can also emit natural radioactive compounds like radon. Construction materials, as well as certain activities such as home improvements and cleaning, emit a number of volatile organic compounds (VOCs), including formaldehyde. Cooking, smoking, and burning incense and wood are sources of particulates and aromatic hydrocarbons and, when burned improperly, may produce carbon monoxide, a deadly odorless gas. Stale air and moisture create the perfect conditions for mold to thrive.

What impact do these pollutants have on our health?

Each compound does something different. Early on, we may experience headaches and fatigue, which can interfere with our ability to function. Certain pollutants cause irritation and inflammation in the throat, eyes and nose. Mold spores are highly allergenic, causing asthma attacks and infections. Neurotoxic chemicals like solvents and insecticides can cause dizziness. Endocrine disruptors affect our hormones. Prolonged exposure to particulates or gases like radon can result in lung cancer.

Are certain people more at risk than others?

We are all affected by indoor air pollution, but children, whose lungs are still developing, are certainly the most vulnerable group. In addition, people with asthma – of whom there are around four million in France – may find their symptoms worsen when they are exposed to allergenic products.

How can we make buildings healthier for children and everyone else?

It takes a multi-step process. It starts with a site analysis and continues through the design stage – choosing the lowest-emitting building materials and finishes, and selecting the right components. When the building is undergoing final acceptance, the air quality must be tested to ensure that no issues arose during the construction phase, with a particular focus on ventilation, given the key role it plays in preserving indoor air quality. Then after six months have elapsed, the air must be tested again with the residents and their furnishings and cleaning products in place, so that adjustments can be made if needed. In one case, a new daycare building had excellent air quality thanks to the care taken during the design and construction phases. Six months on, however, tests showed high VOC levels as a result of their cleaning products and furnishings. On our recommendations, the director of the daycare switched to steam cleaning to solve the problem.

What are the best materials to use?

We must choose carefully when selecting any products that come in contact with indoor air (such as coverings for floors, walls and ceilings). The materials themselves are not good or bad; everything comes down to how they are used and their emissions levels. France has developed a VOC emissions labeling system for construction and decorative materials. It provides useful guidance to builders and consumers, for whom I recommend buying only products and water-based paint with the A+ rating.

What are the best practices for us to implement at home?

While building materials impact indoor air quality for one or two years, the actions of the occupants themselves are the determining factor for pollution levels in their homes after that period. There are user-friendly devices that consumers can use to measure CO2 and formaldehyde levels, and they can take concrete steps to reduce pollutant levels in their homes. This involves refreshing the air several times a day, maintaining the ventilation system, not plugging air holes around woodwork, keeping the space under doors free to promote airflow, removing moisture caused by cooking or drying clothes, and not using tobacco products, incense, air fresheners, insecticides or scented household products.