Which of the following factors can lead to higher concentrations of indoor air pollutants?

Excessive use of volatile substances is a significant factor that can lead to higher concentrations of indoor air pollutants. Volatile organic compounds (VOCs) are commonly found in a variety of products, including paints, solvents, cleaning agents, and personal care products. When these substances are used indoors, they can off-gas, releasing pollutants into the air. The accumulation of VOCs can contribute to poor indoor air quality, resulting in health issues and discomfort for occupants.

Regular cleaning schedules can assist in maintaining indoor air quality by removing dust, allergens, and pollutants, thereby minimizing their concentrations. Low indoor occupancy rates typically lead to fewer emissions of pollutants because there are fewer sources of contaminants, and natural ventilation systems can help dilute and disperse indoor air pollutants, reducing their concentrations. Thus, these factors do not contribute to increased levels of indoor air pollution in the same way that excessive use of volatile substances does.