The main source of atmospheric sulfur dioxide today is ____________.

The main source of atmospheric sulfur dioxide today is ____________.

• A. Power plants
• B. Natural sources
• C. Vehicles
• D. People

Answer: (D)

Sulfur dioxide mainly comes from burning sulfur-containing fuels. Today, the largest contributor is electricity and heat production in power plants that burn coal or oil. When these fuels are combusted, sulfur in the fuel is oxidized to sulfur dioxide and released into the atmosphere. Natural sources like volcanoes do emit SO2, and vehicles contribute some as well, but the scale of emissions from large fossil-fuel power plants typically dwarfs those other sources. The idea that people are the main source doesn’t align with how SO2 enters the air through combustion processes; the dominant pathway is fossil-fuel combustion in power generation.

Sulfur dioxide mainly comes from burning sulfur-containing fuels. Today, the largest contributor is electricity and heat production in power plants that burn coal or oil. When these fuels are combusted, sulfur in the fuel is oxidized to sulfur dioxide and released into the atmosphere. Natural sources like volcanoes do emit SO2, and vehicles contribute some as well, but the scale of emissions from large fossil-fuel power plants typically dwarfs those other sources. The idea that people are the main source doesn’t align with how SO2 enters the air through combustion processes; the dominant pathway is fossil-fuel combustion in power generation.