Smoke Chemistry and Chemical Composition

Chemical Composition of Smoke

Wood Smoke
Nancy Habbas/EyeEm/Getty Images

Smoke is something that we will deal with all throughout our lives, in everyday situations as well as in emergencies. But not all smoke is the same -- in fact, the smoke will vary depending upon what is being burned. So then what, exactly, is smoke made of?

Smoke consists of gasses and airborne particles produced as a result of combustion or burning. The specific chemicals depend on the fuel used to produce the fire. Here is a look as some of the principal chemicals produced from wood smoke. Keep in mind, there are thousands of chemicals in smoke so the chemical composition of smoke is extremely complex.

Chemicals in Smoke

In addition to the chemicals listed in the table, wood smoke also contains a large amount of unreacted air, carbon dioxide, and water. It contains a variable amount of mold spores. VOCs are volatile organic compounds. Aldehydes found in wood smoke include formaldehyde, acrolein, propionaldehyde, butyraldehyde, acetaldehyde, and furfural. Alkyl benzenes found in wood smoke include toluene. Oxygenated monoaromatics include guaiacol, phenol, syringol and catechol. Numerous PAHs or polycyclic aromatic hydrocarbons are found in smoke. Many trace elements are released.

Reference: 1993 EPA Report, A Summary of the Emissions Characterization and Noncancer Respiratory Effects of Wood Smoke, EPA-453/R-93-036

Chemical Composition of Wood Smoke

Chemical g/kg Wood
carbon monoxide 80-370
methane 14-25
VOCs* (C2-C7) 7-27
aldehydes 0.6-5.4
substituted furans 0.15-1.7
benzene 0.6-4.0
alkyl benzenes 1-6
acetic acid 1.8-2.4
formic acid 0.06-0.08
nitrogen oxides 0.2-0.9
sulfur dioxide 0.16-0.24
methyl chloride 0.01-0.04
napthalene 0.24-1.6
substituted napthalenes 0.3-2.1
oxygenated monoaromatics 1-7
total particle mass 7-30
particulate organic carbon 2-20
oxygenated PAHs 0.15-1
Individual PAHs 10-5-10-2
chlorinated dioxins 1x10-5-4x10-5
normal alkanes (C24-C30) 1x10-3-6x10-3
sodium 3x10-3-2.8x10-2
magnesium 2x10-4-3x10-3
aluminum 1x10-4-2.4x10-2
silicon 3x10-4-3.1x10-2
sulfur 1x10-3-2.9x10-2
chlorine 7x10-4-2.1x10-2
potassium 3x10-3-8.6x10-2
calcium 9x10-4-1.8x10-2
titanium 4x10-5-3x10-3
vanadium 2x10-5-4x10-3
chromium 2x10-5-3x10-3
manganese 7x10-5-4x10-3
iron 3x10-4-5x10-3
nickel 1x10-6-1x10-3
copper 2x10-4-9x10-4
zinc 7x10-4-8x10-3
bromine 7x10-5-9x10-4
lead 1x10-4-3x10-3