What does emissions refer to in environmental terms?

Emissions in environmental terms specifically refer to the release of gases or particles into the atmosphere. This includes various pollutants such as carbon dioxide, methane, nitrous oxide, and other harmful substances that can contribute to air pollution and climate change. Understanding emissions is crucial as they play a significant role in assessing environmental impact and are key targets in efforts for pollution control and sustainability initiatives.

In contrast, the other options address related but different concepts. The absorption of toxins by trees refers to the process through which trees and plants filter out pollutants from the air, which is vital for ecosystem health but doesn't define emissions. The storage of carbon in the soil pertains to carbon sequestration, a method of storing carbon to reduce atmospheric levels rather than emitting it. Lastly, the reduction of industrial waste relates to minimizing the by-products produced during manufacturing and does not directly denote emissions, as it focuses more on waste management rather than the release of gases.