When it comes to pollution, very often our thoughts associate it with that of the outside air. The exhaust gases, the various smells seem easy to us to perceive. But the air we breathe in our home environment is also polluted. What are these pollutants and how toxic are they? We spend a very large part of our time indoors: at home, at work or with the children at school. And it happens that indoor air is much more polluted than outdoor air. So what are these chemicals in the home, what are their effects, and how can we protect ourselves from them?
What is indoor pollution?
In theory, the air we breathe contains mostly nitrogen and oxygen, but in reality it contains a variety of substances in minute and varying amounts. Some of these substances are harmless to health, others are toxic in more or less high doses. Part of the pollution in our interiors comes from outside (vehicle traffic, industry, etc.), but also from our homes themselves. Many pollutants are released into the air by building materials, coatings and paints in the home or by volatile particles from furniture and household appliances. In addition, there are chemicals in the detergents used for cleaning, in the fumes given off during cooking or by certain heating appliances, when burning candles or incense sticks, etc.
The air you breathe in your home contains carbon dioxide, which is naturally released by human activities, including the breathing of its occupants. All these products, particles and pollutants gradually accumulate and form what is called indoor pollution. In trying to limit energy losses in houses, we often insulate to the detriment of good ventilation in the house, which leads to a progressive saturation of the ambient air. Because the air quality can be quickly affected by the enclosed space.
What pollutants are there in the air inside homes?
There are two families of indoor air pollutants: primary pollutants that result directly from pollution (nitrogen oxides released by vehicles, sulfur dioxide released during the combustion of fossil fuels, etc.) and pollutants secondary resulting from the chemical reaction of these pollutants with their environment (with UV rays, with the oxygen present in the air, etc.).
There are three main families of products that are harmful to the environment indoors:
Volatile Organic Compounds (VOCs)
Most volatile organic compounds come from exhaust gases, but are also found in many household products and coatings: solvents, wood, glues or paints. They are released indoors, sometimes for years, and affect the air quality in your home. Volatile organic compounds include polycyclic and monocyclic hydrocarbons and aldehydes such as formaldehyde, which are particularly toxic.
Microparticles (MP)
Microparticles are tiny pollutants that float in the air. Most of them are released by heating, car traffic and industry. While some are visible, most are invisible to the naked eye and all the more dangerous.
Carbon dioxide (CO2)
Carbonic acid, also known as carbon dioxide, occurs naturally in the air and is not inherently toxic. Nevertheless, a high concentration indoors can have adverse health effects. In a house, the presence of carbon dioxide can be due to external pollution, but it mainly comes from the people who live there, who release carbon dioxide through their breathing.
Ambient air can also contain various other toxic chemicals such as heavy metals (lead, mercury, cadmium, etc.), combustion residues such as nitrogen oxides, sulfur dioxide and carbon monoxide.
What effects does indoor pollution have on health?
Not all substances present in the ambient air have a direct influence on your health. Some are even harmless or, like ethanol, are present in minute quantities. However, other particles present a danger, in the more or less long term and with varying degrees of toxicity depending on their concentration and the duration of exposure. Among the volatile organic compounds, some substances are considered very dangerous: this is the case of benzene and formaldehyde, which irritate the respiratory tract and are carcinogenic. Therefore, there are strict regulations for products responsible for emitting these VOCs. Microparticles are also potentially dangerous to health, in particular due to their small size. This is because they can penetrate deep into the airways. Heavy metals are also a danger: although they are present in small quantities, they can accumulate in the body over time.
Most indoor air pollutants irritate the airways, eyes and mucous membranes. This is particularly the case for nitrogen dioxide or sulfur dioxide. However, the most toxic product in the short term is carbon monoxide. Invisible and odorless, it can spread through the house due to a faulty heating system.
What are the solutions to fight indoor pollution?
There are solutions to maintain indoor air quality and limit pollution in enclosed spaces. Choose products for your living room (furniture, decorative objects, coverings and cleaning products) that are respectful of the environment and do not present a toxic risk. Remember to have your boiler serviced regularly to avoid the risk of carbon monoxide poisoning. There are also detectors capable of detecting this toxic gas. Also consider installing environmentally friendly houseplants in your home. Their strength lies in the absorption of pollution and in particular VOCs. Even if scientists doubt the real benefits of this phyto-purification and that plants are not enough to completely eliminate pollution from homes, it remains an effective measure to improve air quality.
The essential step in reducing indoor pollution is proper room ventilation. Installing an effective ventilation system and airing it daily are two essential actions. By renewing the air in your home, you will reduce the concentration of gases and particles, and eliminate excess humidity, which is also responsible for respiratory problems and mould.