Dilution air is the air that mixes with which type of gases?

Dilution air is specifically the air used to mix with combustion gases in order to reduce their temperature and concentration, making it safer for the environment and for human health. When a combustion process occurs, it generates exhaust or combustion gases that can be harmful if released without treatment. By introducing dilution air, the harmful components of these gases are diminished through blending, allowing for safer emissions.

In addition to the concept of dilution, it's also vital to understand the role of each type of gas mentioned. Combustion gases arise directly from the burning of fuels, while the other options pertain to varying roles in ventilation and heating but do not specifically refer to the need for dilution. Thus, dilution air's principal function is linked closely to managing combustion gases, highlighting the importance of this process in maintaining air quality and safety in environments where combustion occurs.