Why does smoke inhalation kill people? It reduces the amount of oxygen that the lungs can take out of the air and people die of asphyxiation.
House fires are obviously dangerous, but most people who are caught in a fire don’t die from burns. In 2019, there were 3,704 deaths caused by fire in the US and 75% of them were caused by smoke inhalation. Smoke inhalation can also kill people even after they have been rescued from a fire.
Why is smoke inhalation so dangerous? Well, what is smoke? When something burns, atoms of molecules combine with the atoms in the fuel that is burning and release energy. To be able to do this, they have to have enough energy in the first place, which is why a fire won’t start without sufficient heat. The amount of energy required depends on the thing that is burning. If there is enough oxygen, there won’t be any smoke because every atom in the thing being burned will combine with the oxygen and only water and carbon dioxide will be left. If there isn’t enough oxygen, solid particles of the fuel and gas are released into the atmosphere, forming smoke. The gases are carbon dioxide and carbon monoxide. There are many other chemicals in the smoke, depending on what is being burned.
Smoke inhalation is dangerous in four ways. Firstly, the carbon monoxide in the smoke decreases the amount of oxygen the body can take in. When we breathe, we take the air into our lungs and the oxygen passes into our blood through the blood vessels that are close to the surface in the alveoli, which are the little sacks that cover our lungs. In a fire, the amount of oxygen in the air is already lower than usual because the fire uses it as a fuel, so your body is already running on an oxygen deficit. The air we breathe in is thick with smoke and carbon monoxide. Carbon monoxide can combine with red blood cells over 200 times more easily than oxygen, so our blood very quickly becomes saturated with it. Your body stops being able to absorb oxygen and you start to suffocate. It also takes a long time to get carbon monoxide out of the body. People exposed to smoke and carbon monoxide can very quickly become disorientated, drowsy, and get headaches. The heart will begin to beat faster to compensate for the lack of oxygen in the blood and this can ultimately lead to unconsciousness, heart attacks and death. If someone is pulled out of the smoke fast enough, breathing pure oxygen can help to keep them alive long enough for the body to get rid of all the carbon monoxide, but that depends on how much carbon monoxide they have inhaled.
The second way that smoke inhalation is dangerous is the particles that are suspended in the smoke. These particles travel down into the lungs where they become stuck, clogging up the lungs and airway. These particles damage the lining of the lungs, but they also trigger a reaction from our immune system. When there is a foreign particle stuck somewhere in our body, the immune system causes swelling to allow white blood cells in to clear out the area. This swelling in the lungs can cause the lungs to fill with fluid and to collapse. It makes breathing extremely difficult.
The third way is down to the chemicals that are in the smoke. Everything that burns releases some kind of particle, but a lot of compounds also release toxic chemicals. Our houses are filled with plastic and other items that release chemicals when they burn. These can be cyanide, hydrogen chloride, phosgene, sulfur dioxide, ammonia, and toxic aldehyde chemicals. All of these are dangerous in their own right. They can poison the body, or cause damage to the lungs. They are all difficult to remove as well.
The fourth way that smoke inhalation is dangerous is because of its heat. When you breathe smoke in from a fire, it is still very hot and it can cause burns to the throat and the lungs. This can also cause a swelling response, making it even harder to breathe.
Because of all these factors, even people who are rescued from fires can go on to get very sick and die in hospital. It is very difficult to recover from smoke inhalation and even if you do, there can be lasting effects. So, why does smoke inhalation kill people? Because it asphyxiates, burns, and poisons people. And this is what I learned today.
Sources
https://en.wikipedia.org/wiki/Smoke_inhalation
https://www.fireco.uk/the-killing-fumes-why-smoke-is-more-deadly-than-fire/
https://www.webmd.com/lung/smoke_inhalation_treatment_firstaid.htm
https://www.sciencelearn.org.nz/resources/748-what-is-smoke
https://www.qrg.northwestern.edu/projects/vss/docs/propulsion/2-how-do-things-burn.html
https://health.ny.gov/environmental/outdoors/air/smoke_from_fire.htm
https://www.cityofandrews.org/fire_marshal/carbon_monoxide.php
https://www.msdmanuals.com/en-jp/home/injuries-and-poisoning/burns/smoke-inhalation
https://www.mayoclinic.org/diseases-conditions/carbon-monoxide/diagnosis-treatment/drc-20370646