What is "what else is produced during the combustion of propane?

In addition to carbon dioxide (CO2) and water (H2O), combustion of propane also produces small amounts of other byproducts such as carbon monoxide (CO), nitrogen oxides (NOx), and sulfur dioxide (SO2). These byproducts can have negative environmental impacts and contribute to air pollution. The exact amount of these byproducts produced during combustion can vary depending on the efficiency of the combustion process and any impurities present in the propane. It is important to have proper ventilation and combustion equipment to minimize the production of these harmful byproducts during the combustion of propane.