Which of the following is a set of techniques for controlling indoor air pollutants?

• A. Dilution, Extraction, Source Control
• B. Filtration, Ventilation
• C. Dilution, Ventilation, Filtration
• D. Extraction, Filtration, Dehumidification

Answer: (A)

Controlling indoor air pollutants hinges on three main levers: reducing emissions at the source, diluting contaminants with outdoor air, and removing pollutants from the air near where they’re generated. Dilution lowers concentration by bringing in fresh outdoor air. Extraction (local exhaust) pulls contaminants away from the breathing zone before they spread. Source control prevents pollutant emissions from entering the indoor environment in the first place. When you combine dilution, extraction, and source control, you cover all the essential ways to manage IAQ.

Other options mix methods that either remove pollutants without addressing emissions at the source or focus on moisture-management rather than pollutant control, so they don’t provide the same comprehensive approach. This triple set—dilution, extraction, and source control—best reflects a complete strategy for controlling indoor air pollutants.