What do elevated CO2 levels in indoor environments indicate?

Elevated CO2 levels in indoor environments primarily indicate poor ventilation. When a space is not adequately ventilated, the air cannot circulate properly, leading to the accumulation of CO2 produced by occupants and various indoor activities. Effective ventilation is essential for maintaining indoor air quality, as it helps to dilute and remove indoor pollutants, including CO2, ensuring a healthier environment for occupants.

While high occupant density can also contribute to increased CO2 levels, the root cause typically centers around ventilation inadequacies. Excessive air conditioning use does not inherently lead to elevated CO2; rather, it may improve air circulation if designed properly. Additionally, abundant outdoor air sources would normally help to reduce CO2 levels rather than increase them. Thus, the connection between elevated CO2 levels and poor ventilation is the most direct and significant factor in this context.