Which of the following is an example of a hazardous substance based on combustion outputs?

• A. Carbon Dioxide
• B. Water Vapor
• C. Sulfur Dioxide
• D. Steam

Answer: (C)

The identification of sulfur dioxide as a hazardous substance based on combustion outputs is accurate due to its known toxicological effects and environmental impacts. Sulfur dioxide is primarily produced by the burning of fossil fuels containing sulfur, such as coal and oil, and is a significant contributor to air pollution.

When sulfur dioxide is released into the atmosphere, it can lead to the formation of acid rain, which has detrimental effects on the environment, including damage to forests, soil, and water sources. Additionally, exposure to sulfur dioxide can cause respiratory problems and irritate the eyes, nose, and throat, making it a notable concern from a public health perspective.

In contrast, substances like carbon dioxide and water vapor are byproducts of combustion but are not classified as hazardous in the same way. While carbon dioxide is a greenhouse gas and contributes to climate change, it is not toxic at typical atmospheric levels. Water vapor is simply a non-toxic product of combustion. Steam, essentially just water in vapor form, also does not pose the same health risks as sulfur dioxide. Thus, sulfur dioxide stands out as a clear hazardous substance in this context.