What is a common sign of poor IAQ that facilities managers should monitor?

• A. Excessive lighting
• B. High humidity only
• C. Elevated CO2 levels or noticeable odors and headaches among workers
• D. Low noise levels

Answer: (C)

When thinking about indoor air quality, ventilation effectiveness is the most practical signal to monitor. Elevated CO2 levels show the space isn’t bringing in enough fresh outdoor air for the number of people inside, so exhaled CO2 accumulates and occupants can feel less alert or more uncomfortable. Keeping CO2 in a reasonable range (a common target is below around 800–1000 ppm in typical occupied spaces; higher readings suggest under-ventilated conditions that can allow other pollutants to build up) is a direct indicator that air exchange needs attention. In addition, noticeable odors and headaches among workers point to the presence of airborne contaminants such as VOCs or irritants that ventilation or filtration isn’t adequately removing. These signals together give a clear cue that IAQ may be poor and action is needed. Excessive lighting and low noise levels don’t reflect air quality, and high humidity alone isn’t a definitive IAQ sign, though it can contribute to issues like mold. So the combination of elevated CO2 and reports of odors or headaches is the most informative sign for facilities managers to monitor.