n. The chemical conversion of complex hydrocarbons in fuel to carbon dioxide, carbon monoxide, water vapor, water droplets, carbon particles, and other hydrocarbon gasses.
Smoke production is part of the pyrolysis and combustion processes. During pyrolysis, heat causes chemical reactions within woody fuel. These reactions lead to the release of a variety of hydrocarbon gasses into the pores of the fuel and into the air. During combustion, gases produced during pyrolysis and hydrocarbons, such as cellulose and lignin, react with oxygen in the air, creating a wide range of chemicals including water vapor, carbon dioxide, and carbon monoxide. Microscopic particles, mostly carbon, also enter the air during combustion. These processes that create the gases and particles mixed in the air constitute smoke production.