Which non-gaseous pollutant is produced from burning fuels?

Burning fuels leads to the release of various pollutants, and one notable non-gaseous pollutant produced in this process is solid particles, commonly referred to as soot. Soot consists of fine carbon particles that result from incomplete combustion of carbon-containing fuels, such as coal, oil, and gas. These particles can contribute to air pollution and have adverse effects on human health and the environment.

While carbon monoxide and oxides of nitrogen are also byproducts of fuel combustion, they are gaseous pollutants. Water vapor, although produced during combustion, is typically categorized as a greenhouse gas rather than a pollutant in the context of air quality. Thus, when discussing non-gaseous pollutants specifically resulting from burning fuels, solid particles like soot are the correct answer.