All of the following are sources of PM except

All of the following are sources of PM except

• A. Volcanoes
• B. Road construction
• C. Combustion of biofuels
• D. Incomplete natural gas combustion

Answer: (C)

Particulate matter comes from both natural events and human activities that release tiny particles into the air. Volcanoes eject ash and mineral particles that contribute to PM. Road construction and traffic stir up dust and wear particles from roads, tires, and brakes, all of which are PM. Combustion of biofuels—such as wood, crop residues, or other biomass—produces soot and organic particles, especially when combustion is incomplete or inefficient. Incomplete combustion of natural gas can also release unburned hydrocarbons and soot particles that add to PM levels. Because each of these activities can emit particulate matter, there isn’t a true exception among them; PM is generated from both natural processes and common human activities like burning biofuels and other fuels.

Particulate matter comes from both natural events and human activities that release tiny particles into the air. Volcanoes eject ash and mineral particles that contribute to PM. Road construction and traffic stir up dust and wear particles from roads, tires, and brakes, all of which are PM. Combustion of biofuels—such as wood, crop residues, or other biomass—produces soot and organic particles, especially when combustion is incomplete or inefficient. Incomplete combustion of natural gas can also release unburned hydrocarbons and soot particles that add to PM levels. Because each of these activities can emit particulate matter, there isn’t a true exception among them; PM is generated from both natural processes and common human activities like burning biofuels and other fuels.