In the world, 11 hectares of forests are being burned every second, a figure that makes you dizzy. Millions of hectares of forests are burned each year and these fires have a significant impact on air pollution. The phenomenon is global and in industrialized countries it is particularly acute, as in Australia or the United States (California), but other countries are not spared. In 2018, Greece, Portugal, Sweden and the United Kingdom were particularly affected by large-scale forest fires.
Are we polluted by fire smoke in the city?
Likewise, our cities are regularly exposed to flames and if emblematic fires such as the recent Notre Dame de Paris in April 2019, the World Trade Center in New York (2001), the Fenice in Venice (1996), the Liceo in Barcelona (1994) or the Windsor Castle in London (1992) are remembered, studies by the International Technical Committee for Fire Prevention and Extinction (CTIF) show that in major urban centres around the world there are thousands of fires each year.
In 2016 CTIF counted 40,000 fires in New York, 20,000 in London, 13,000 in Paris, 7,000 in Berlin and Madrid, 5,000 in Moscow... On average 25% of these fires concern buildings but as we will see, even if the fire is not directly in your home and if it affects a forest, a vehicle, a factory, a wild landfill... you can still be a collateral victim.
How will the smoke from a fire pollute your indoor air?
Fires are a problem that seems very abstract to us until the day when we are affected. The extreme case is when your home is burned down, but you can suffer serious consequences even if you are located miles from a fire if you have been contaminated by smoke and its toxic components. After a fire, the quality of the indoor environment of the region's homes is affected and can make houses extremely toxic, while everything appears normal to the naked eye and we congratulate ourselves on having escaped the disaster.
We rarely worry about the effects of smoke on human health in our homes after a fire that did not directly affect us when in reality the consequences can be dramatic. Contamination of your home or office with toxic combustion residues can have serious health repercussions.
Imagine the following scenario, you live in a cosy house and there is a fire in the distance. You are not affected by the flames but the smoke, blown by the wind, has come into your home. Visible or not, this smoke has entered your house through windows or through leaks and ventilation systems. Once inside, the toxic components of smoke settle on all solid surfaces, in the ventilation system, on floors, walls, furniture, clothing, furniture textiles, carpets and upholstery.
In the best of scenarios, you have thoroughly ventilated and cleaned your home to remove soot and burning odours. You have got rid of the vast majority of visible residues and odours have dissipated, but in fact you have only treated the most volatile components of the pollution. There are remaining semi-volatile organic compounds (COSV), from the polycyclic aromatic hydrocarbons (PAHs) family, such as benzo(a)pyrene, phenanthrene, benzo(a)anthracene, and benzo(b)fluoranthene. These combustion residues will continue to be a long-term source of contamination in your home or office for days, weeks and months after the fire.
PAHs stick to building materials, furniture, impregnate carpets and fabrics and even adhere to stainless steel. This long-lasting contamination of the indoor environment results in chronic exposure of occupants to highly toxic substances that have a significant impact on their health. PAHs are also found on fine dust particles (PM10 and PM2.5) that are inhaled and penetrate deep into the respiratory tract to the pulmonary alveoli.
What are the health effects of smoke pollution?
This exposure results in respiratory tract irritation, initiation and aggravation of asthma attacks, development of chronic diseases such as bronchitis, effects on the immune system and in the most extreme cases lung, skin or bladder cancer...
Another consequence that does not come to mind but which was highlighted by a study conducted in the United States between 2008 and 2010 and published by Environemental Health Persecpective: an increase in cardiac diseases.
Most PAHs are classified as carcinogenic by the World Health Organization (WHO). They are also suspected of being endocrine disrupters, i. e. substances capable of altering the normal hormonal functioning of the body (chemical message).
Young children are more sensitive to air and indoor environmental pollution and are particularly exposed to PAHs. Indeed, they have accelerated breathing and therefore inhale significant quantities of these toxic substances and because they often play at ground level, they can also ingest these contaminated dusts. They are therefore exposed to these substances in greater quantities than adults.
How do you know if your home has been polluted by smoke?
Only a laboratory dust analysis can determine the actual degree of contamination in a home or office and thus assess potential health risks. The analyses are also very useful to verify the effectiveness of the decontamination work carried out. There are now tests available to measure the most toxic combustion residues for health.