Industrial Hygiene – What is Soot and Why is it Dangerous?

The word “soot” sounds so simple and harmless. To some, it conjures up images of campfires and candles, and perhaps a charming dance number from Mary Poppins.

In fact, soot is anything but simple and is certainly not harmless.

Soot includes the fine black particles, chiefly composed of carbon, produced by incomplete combustion of coal, oil, wood, or other fuels. Soot can consist of acids, chemicals, metals, soils, and dust. The common trait of soot particles is that they are extremely tiny – 2.5 micrometers or smaller in diameter. This is smaller than dust and mold, and is about 1/30 the diameter of a human hair.

This combination – extremely small size and toxic composition – is what makes soot so dangerous. It can travel deep into the lung, where the compounds it consists of can do some serious damage.


Soot is the byproduct of the burning of fossil fuels. This includes burning coal for electricity or industrial fuel, manufacturing, oil refining, and motor vehicles.

Soot enters the environment either as a solid particle or as a gas which turns into a particle after it has been released. These particles can end up very far away from their site of origin.

Soot can also become a problem following a fire. A common house fire results in the burning of a wide variety of materials, from wood and paper to plastics and other synthetic items. This results in soot contamination, and poses a serious cleanup problem.

Soot can also negatively impact Indoor Air Quality. Excessive use of candles in an indoor environment can lead to a buildup of soot. This sometimes leads to “ghosting”, where the tiny soot particles cling to areas of walls and ceilings due to electrostatic attraction. This can also happen when fireplaces are insufficiently ventilated. If you see these “soot ghosts” in your home, you may want to rethink your level of candle usage or have your chimney evaluated. 

Risks – Health & Environment

Compounds from soot – sulfur dioxides and nitrogen oxides – combine with moisture to form acid rain, which worsens water quality, damages soil and crops, and changes nutrient balances in various ecosystems.

Breathing the tiny particles can cause coronary heart disease, asthma, bronchitis, and many other respiratory illnesses. 

Research has also shown that many premature deaths are directly related to soot in the environment. Particle exposure leads to around 20,000 premature deaths in America each year. Many of these deaths were caused by soot-related diseases. Data also show that soot annually causes almost 300,000 asthma attacks and 2 million lost workdays due to repiratory problems.

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2 Thoughts to “Industrial Hygiene – What is Soot and Why is it Dangerous?”

  1. People noamllry pay me for this and you are giving it away!

    1. admin

      Thanks dear, I appreciate you comments. Cheers…….

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