Flammability methane-oxygen combustion

Smoke. Smoke is matter consisting of very fine solid particles and condensed vapor. Fire gases from common combustibles (such as wood) contain water vapor, carbon dioxide, and carbon monoxide. Under the usual conditions of insufficient oxygen for complete combustion, methane, methanol, formaldehyde, and formic and acetic acids are also present. These gases are usually evolved from the combustible with sufficient velocity to carry droplets of flammable tars which appear as smoke. Particles of carbon develop from the decomposition of these tars they are also present in the fire gases from the burning of petroleum products, particularly from the heavier oils and distillates. 

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