by Dr. Victor Chernov
Burning wood is one of the most polluting ways to generate energy and heat. don't do it
Imagine the following image: it's winter outside. You are in an armchair, a cat is sitting on you (which does not come out). There is a carpet on the floor and a dog is napping on it. You sip your favorite drink and relax by the fireplace, feel the warmth of the fire, enjoy the sound of burning logs, and enjoy the smell. Idyll in its embodiment. so no. You are endangering yourself and the environment with a variety of deadly diseases. Burning wood, while probably one of the oldest forms of generating energy, is also one of the most harmful and unhealthy ways to do so.
To understand why, you have to remember how fire works. The combustion process is a process in which fuel and air react in an exothermic way - that is, heat is released. That's the goal. But in nature, matter is not lost, but turns into other matters. What materials? In an ideal combustion of air and hydrocarbon fuel (a substance that contains carbon and hydrogen) carbon dioxide and water vapor are obtained. What is an ideal fire? In an ideal fire, all the fuel and all the air undergo a chemical reaction. Conversely, in a non-ideal fire, if the air runs out before the fuel then the flame is rich (in fuel) and if the fuel runs out before the air, then the flame is lean (in fuel). Note that I wrote "flame". A flame is the area where the fuel and air react, and the determination of whether the flame is rich or lean is made according to the concentration of the fuel and air in its environment.
Burning is a chemical reaction. In a chemical reaction, a molecule or atom has the opportunity to connect with another atom or molecule, or to break existing connections. As we raise the temperature, we will increase these opportunities. At a high temperature and in the presence of oxygen (poor flame) the oxygen will take advantage of the opportunities to connect with hydrocarbon molecules either as oxygen itself, or as part of another molecule. But what happens in an area rich in fuel? Other molecules will precede it. This process, in which hydrocarbons are exposed to high temperature and there is little oxygen is called "pyrolysis".
Uncontrolled pyrolysis is responsible for the creation of many of the pollutants. A simplistic example of pyrolysis is a process where ethylene gas (C2H4), the gas that apples release when they ripen, turns into acetylene (C2H2), and 3 molecules of acetylene turn into benzene (C6H6). Of course, this is not the whole process (we did not talk about what happens to the six hydrogen atoms), but in the end we get benzene, which is both a dangerous and carcinogenic substance in itself [1], and also a building block of soot particles (soot damages the respiratory tract and blood vessels [2 ]). If there was enough oxygen in the environment, this would not happen, but when there is no oxygen in the environment and there is a high temperature, many pollutants are obtained.
The pyrolysis process is a general process, which occurs in any hydrocarbon burning, but in the burning of wood it is particularly problematic. The way to make sure there is enough oxygen is by better mixing of fuel and air. This is what happens in home stoves - they mix the cooking gas and the air before the fire. This can be determined by the color of the flame - a blue or transparent flame is a flame without particles. In wood this is not possible. Unlike liquid fuels, wood does not evaporate before burning. Wood and coal burn in "surface combustion" - that is, the initial combustion reaction occurs on the surface of the wood. In order for the fire to occur, the wood must be heated to several hundred degrees (this is the reason why paper, furniture and wood do not burn every day, even though there is a lot of oxygen around). But at a few hundred degrees, pyrolysis already begins in the depth of the wood, which is not exposed to oxygen, and pollutants begin to form.
For this reason burning wood is very polluting. According to the US Environmental Protection Agency, the most efficient wood fireplace emits 37 times more polluting particles than an average oil stove [3], with oil stoves themselves being considered polluting and not recommended for heating. Relative to a domestic gas stove, there are 60 times more polluting particles. The special smell of burning wood? These are aromatic substances. The name does sound romantic, but its romance is like the romance of Romeo and Juliet - there is mostly death there. Many of the aromatic substances (of which the benzene we mentioned above is a part of) are carcinogenic and harmful substances.
The particulate pollution significantly lowers the air quality around and inside the heated building. Yes, the pollution is also inside the building. Even if the fireplace is not open, some of the particles will still enter the building. The evidence for this is that next to the fireplace usually a black deposit will form over time. This sediment is the part of the pollution that you see; What floats in the air is no less harmful, but invisible. Particulate pollution is only one type of pollution from burning wood. Burning wood, being poor in oxygen, also emits a significant amount of carbon monoxide (CO) - a colorless and odorless poisonous gas. In the event of a problem with the fireplace's exhaust system, the results could be fatal.
Particulate pollution is not limited to fireplaces only. During the celebrations of the Jewish holiday every year, a sharp increase in this pollution is measured throughout the country [4]. Yes, even a simple bonfire is not friendly to your health and the environment, and canceling bonfires this year is a welcome step.
Burning wood, whether for heating the house, or whether for recreation and celebration outside is a sick evil, in its most literal sense. As a result of burning wood, the exposure to carcinogenic substances increases, the danger to the respiratory tract and blood vessels increases and there is a chance of dying due to carbon monoxide poisoning. Currently there is no way to burn wood cleanly. If your health and the health of your neighbors is important to you - avoid burning wood or any other solid fuel.
Sources and further reading
[1] A little description of the use of benzene and its effects
[3] US Environmental Protection Agency Wood Stove Replacement Program Information File (pdf)
More of the topic in Hayadan:
5 תגובות
"And there is a chance of dying from carbon monoxide poisoning."
Oh what confusion. The chance that you will be electrocuted by inserting a plug into a plug is tens of times higher.
The correct solution for heating is the use of electricity.
Heating with heat pumps is more efficient than heat production of any kind.
Electricity production will become greener and with the potential to be from renewable and very clean sources (solar, wind and more).
The right thing to do, for the little citizen, is to reduce energy consumption and travel in general.
Burning wood in small quantities and in efficient facilities such as a rocket stove is a process with high efficiency and sustainability and provides a solution, for example, to the trimmings we have in the garden (instead of transporting it by truck to wherever it is, and treating it there with expensive methods).
The real alternative to that cut is not burning oil or electricity, but the entire process of producing and transporting the oil or electricity to the house + burning oil or electricity consumption. When compared like this, using an efficient wood stove takes fossil fuel use with one hand tied behind your back
It is important for me to add that gathering wood for a fire is not good for nature and us.
The branches that fall from the trees are used as part of nature's ecosystem. For example, they prevent weeds from growing, keep the soil moist, use breeding farms for insects and micro-organisms that enrich the soil, etc.
And as mentioned, the smoke is full of pollutants that we don't want to breathe
In my opinion, if there is a need for fire (danger, insects, extreme cold or lack of other means of cooking), it is better to chop wood that is not on the ground or to recycle other people's bonfires
Thanks
Burning fossil fuels in undirected facilities can be much more polluting than burning wood in unsuitable facilities. The trend today in the world is to switch to burning wood for heating purposes in stoves that know how to create optimal combustion conditions - and this is also the position and purpose of the article of the EPA on which the esteemed writer relies: to switch to the use of quality facilities.
The use of wood and biomass in general for energy production also has many advantages, including reducing the emission of greenhouse gases, and it is considered a renewable energy in contrast to the fossil fuels to which the writer refers.