The Notre-Dame de Paris fire on the 15th of April 2019 released very large quantities of smoke containing combustion residues and lead into the atmosphere for several hours. Indeed, between 260 and 400 tonnes of lead was present in the roof, which burned almost entirely. Residues of this metal, which is very toxic to humans, have been released into the atmosphere.
How can we know which districts of Paris and the surrounding area were most affected by this accidental lead pollution?
Knowing that at the time of the fire a wind of 3 m/s was blowing from the East-South-East direction, it can be deduced that in one hour's time the smoke had travelled up to 10km, spreading highly toxic substances over a very wide area as the fire lasted several hours.
The dust particles contaminated by aromatic hydrocarbons (PAHs) and lead were therefore probably pushed towards the areas located to the west of Paris, most likely the 1st, 7th, 8th and 16th districts and to a lesser extent the towns located downstream such as Neuilly-Sur-Seine, Courbevoie, Nanterre, Rueil-Malmaison...
Is your house, apartment or office located in the smoke diffusion zone of the Notre-Dame fire?
If so, your indoor environment is probably contaminated with lead and PAHs and you are potentially exposed to these toxic substances.
In a press release dated 9 May 2019, the authorities, through the Agence Régionale de Santé Île-de-France and the Préfecture de Police de Paris, indicated that:
Samples taken in the surrounding area show the presence of residual lead dust deposits in the immediate surroundings of the cathedral: - On the cathedral square, and on the surrounding roadway, with a very high point presence of lead in the soil, at levels of about 10 to 20 g/kg soil, compared to the High Public Health Council benchmark value of 0.3 g/kg (1). These areas are currently closed to the public; - In the upper floors of administrative offices overlooking the cathedral (dust).
Recommendations were made and residents of the boroughs concerned were invited to have their homes cleaned up to eliminate these highly toxic dusts.
Cleaning instructions have been given. This involves cleaning homes and offices by limiting the resuspension of dust deposited on the floor, using moistened fabrics rather than a broom. Vacuum cleaners equipped with HEPA filters can also be used.
Although the authorities are reassuring, there is a risk of contamination of houses, apartments and offices with lead residues. This metal has health effects from low doses of exposure that have a known impact on the health of pregnant women, infants and newborns.
In addition to lead, whose health effects are now well known (lead poisoning, neurological disorders, etc.), the fumes also contained PAHs. These aromatic chemical molecules are formed during combustion processes. These organic chemicals are also very toxic to humans. Benzo(a)pyrene is classified as a known human carcinogen (Group 1) by WHO and most of these chemicals are classified as possible or probable human carcinogens (Groups 2A and 2B). In addition, they have endocrine disrupting effects and act on the body at very low doses. For these reasons, it is recommended to limit exposure to these toxic substances (lead and PAH) as much as possible.
How can you be sure that your home is not contaminated with lead and PAHs?
Lead and PAHs are present in the dust. The research and measurement of these substances must be carried out in the dust deposited on the ground. Several methods can be used to collect dust: a pump equipped with a filter on which the dust settles, wipes passed over the surfaces to collect the deposited dust and the use of a filter placed on your household vacuum cleaner.
The use of a pump requires the intervention of a trained technician to perform the sampling for several hours to several days. This type of sampling is therefore the most expensive.
Collecting dust with a wipe is relatively inexpensive but does not allow the results to be directly linked to the amount of pollutant present in the dust that is breathed.
Dust sampling with a domestic filter and vacuum cleaner followed by laboratory testing is the most economical and informative technique for indoor air pollution by lead and PAHs. In addition, it allows the results to be directly linked to the amount of pollutant present in the air inhaled at home and to accurately assess exposure to these toxic substances.
What should I do if lead contamination is found in my home or office?
Conventional cleaning can remove most contaminated dust particles. However, soot consists of particles that stick to surfaces and can be difficult to remove. In addition, the finest particles (PM10) that make up the inhalable fraction are not visible.
To reduce the level of lead and PAH contamination in a home or office, several actions are possible. First of all, it is advisable to provide regular and intense ventilation by opening the windows and creating a draft. This aeration must be done at least twice a day and for a period of 10 minutes. Clean furniture and object surfaces, including children's toys. Carpets, carpets, upholstery foams, lint can store large amounts of dust and it is advisable to wash them or vacuum them with a HEPA filter that will fix the dust particles. Finally, it is also possible to use an indoor air treatment and purification system. At a minimum, it must be equipped with a HEPA filter and an activated carbon filter.
We spend more than 80% of our time in confined environments in which pollutants are accumulating. Since we breathe 12 kg of air per day in comparison to 1 kg of food and 2 kg of water, inhalation is the main source of human exposure to pollution. Controlling the quality of the indoor air you breathe is therefore essential to staying healthy.