Final answer:
Fine particles of ash from solid-fuel furnace waste gases are called particulate matter, which includes smoke and dust potentially harmful to health and environment.
Step-by-step explanation:
The fine particles of ash recovered from the waste gases of a solid-fuel furnace are commonly referred to as particulate matter. This particulate matter can consist of smoke, dust, or other tiny particles that can be harmful to the environment and human health. Combustion processes, such as the burning of coal or wood, release various pollutants, including sulfur oxides (SOx), nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO₂), along with particulate matter. The type of particulate matter that specifically comes from the combustion of solid fuels is often further described as fine-grained ash. In industrial settings, capturing this particulate matter from waste gases is essential for pollution control and is often facilitated by filtration systems. Depending on the cleanliness, recovered ash can sometimes be recycled for uses such as landfill covers, road construction, or in the creation of cement blocks.