Although fire detectors are mandatory for homeowners in many countries (UK, USA, Canada, France...) the fact remains that every year there are hundreds of thousands of domestic fires. To give an order of magnitude, in the United Kingdom the number of domestic fires per year is around 40,000, in France it is estimated at more than 200,000 and in the United States at 1.3 million.
About 20% of domestic fires take place in the kitchen and generally have one of three causes: faulty or overloaded electrical installations, cluttered heat sources (radiators, halogens...), the toaster or a kitchen left unattended while the gas is on or oil is heating.
What are the chemical pollutions formed during domestic fires?
During a fire, the temperature can rise to more than 1000°C. The combustion of materials at high temperatures produces gases and soot containing toxic chemicals, in particular aromatic Volatile Organic Compounds (VOCs) and Polycyclic Aromatic Hydrocarbons (PAHs).
This natural phenomenon is amplified by the fact that our modern homes contain a large number of objects made of synthetic materials such as plastic, paint or chipboard. The main VOCs generated during fires are benzene, naphthalene, toluene, ethylbenzene and xylenes). The list of PAHs produced during fires is longer and a selection of 16 PAHs has been chosen as a reference by the US Environment Agency and many other countries.
Among the PAHs are Benzo[a]pyrene, Benzo[a]anthracene, Chrysene, Benzo[k]fluoranthene, Benzo[b]fluoranthene and Naphthalene which are pointed out by the WHO (World Health Organization).
What are the health effects of VOCs and PAHs?
Aromatic VOCs have chemical molecules that are volatile at room temperature. They are present as gases in the air we breathe. PAHs are low-volatility organic substances. They are present in a liquid or solid state and attached to fine particles in the air we breathe.
VOCs are irritating to the respiratory tract: nose, mouth, throat, trachea and lungs. They have an aggravating effect on diseases of the respiratory system (emphysema, asthma, COPD).
The toxicity of combustion residues is now recognized by health authorities and these substances can be carcinogenic, mutagenic, reprotoxic (CMR) and act as endocrine disruptors.
Some substances accumulate toxic effects. Benzene is a proven human carcinogenic VOC and also has mutagenic effects. Benzo(a)pyrene is carcinogenic, mutagenic, reprotoxic and endocrine disrupting. These two chemical molecules are examples of products formed during a fire.
The lists of VOCs and PAHs are long, but everyone will have understood that chronic exposure to these substances presents serious risks to the health of the occupants.
Why test for VOCs and PAHs after a home fire?
In the case of a fire, even if the fire was quickly brought under control, the room affected by the flames, smoke and soot is heavily contaminated with aromatic VOCs and PAHs.
Ashes and soot from a fire contain VOCs and PAHs in very high quantities.
After the fire, the landlord or tenant makes his fire declaration to the insurance company that covers the burned place, whether it is a home or a business premises, in order to report the claim.
Without personal protective equipment, acute exposure to VOCs and PAHs is very high in burned areas.
The insurance company quickly appoints an expert who comes to ascertain and estimate the amount of damage. The expert will visually inspect the apartment or house and declare that the burned room needs the intervention of a fire restoration company.
The insurer will then instruct the fire restoration company to take care of the burned room. Once the intervention has been completed, the visible traces of the damage have disappeared and things could end there.
However, the toxic substances (aromatic VOCs and PAHs), contained in the smoke and soot, were not confined to the burned room but spread to the adjacent rooms and, if there were floors, carried by the hot air, they went to contaminate the upper floors.
Rooms adjacent to the disaster area are also affected by the pollution from the fire.
This contamination is generally not visible to the naked eye and few insurance experts are aware of this problem. As a result, nothing will be done and the occupants will be exposed to these toxic pollutants.
It is now up to you to ask for a measurement of the pollution linked to the fire.
A fire pollution test allows you to know the level of contamination of each room and to know which other rooms need to be decontaminated.
Measuring pollution after a fire prevents the effects of PAHs on the health of the occupants
Once the premises have been cleaned, decontaminated and renovated, a measurement of the pollution allows the effectiveness of the clean-up to be assessed and the absence of health risks to be confirmed.
Do toxic substances disappear on their own?
Pollution induced by the combustion of materials produces aromatic VOCs and PAHs.
VOCs are volatile and disappear quickly once the burnt waste is removed and the premises are ventilated.
PAHs are fixed on soot particles that stick and seep everywhere. Aromatic molecules are very stable chemical compounds that degrade very slowly. They will therefore be very persistent in the indoor environment after a fire.
PAHs are very stable pollutants that will persist in the indoor environment for a long time.
How to assess the level of pollution after a fire and what are the sanitary reference values?
Pollutants from fires are present in the ambient air: VOCs in gaseous form and PAHs on dust and soot particles.
The measurement of aromatic VOCs makes it possible to assess indoor air pollution. The results can be compared with the Indoor Air Quality Guidelines (IAQG). These are limit values above which improvement actions are recommended when they are exceeded.
Accurate measurement of PAHs in dust enables the contamination of the indoor environment to be assessed. The results can be compared to different reference systems such as the results of PAH measurement campaigns in housing, the maximum levels tolerated to consider a waste as inert and non-hazardous, the reference threshold proposed by the WHO for o(a)pyrene, the thresholds considered for soil pollution.
YOOTEST proposes a solution to easily measure indoor air pollution by fire residues. You take a dust sample which will be analysed to measure precisely the pollution present in the dust. The use of this fire pollution test is essential to assess the risks of exposure to fire pollution.
It is advisable to measure the fire pollution in the rooms adjacent to the affected area to measure the extent of the pollution.
After renovation work, a pollution test is done to evaluate the effectiveness of post-fire decontamination and to check that the situation has returned to normal.