What fuels burn without the production of smoke?

Alcohols and propane are examples of fuels that can burn cleanly, producing little to no smoke under ideal combustion conditions. When these fuels combust efficiently, they mainly produce water vapor and carbon dioxide, which are less visible compared to smoke that contains particulate matter and other byproducts from incomplete combustion.

In contrast, wood and paper, coal and charcoal, as well as plastic and rubber typically yield significant smoke during combustion. Wood and paper can generate smoke due to the presence of lignin and cellulose, while coal and charcoal often produce smoke because of impurities and incomplete burning. Plastics and rubber also release a variety of hazardous compounds and smoke when burned, making them less clean-burning fuels. Hence, alcohols and propane are preferred choices for applications where minimal smoke production is essential, such as in indoor heating or cooking where air quality is a concern.