The air movement from a warm-air heating system may cause __________.

The correct answer highlights how the operation of a warm-air heating system can lead to indoor air-quality issues, particularly through the movement of air that can disturb dust and other particulates that may be present in the environment.

As warm air is circulated throughout the space, it can lift and agitate these particles, causing them to become airborne. This increases the likelihood of residents inhaling dust, allergens, and other contaminants, which can negatively impact health, particularly for those with respiratory conditions or allergies.

Warm-air heating systems are often equipped with filters, but if these filters are not properly maintained or if the system is running in an environment with high dust accumulation, the effectiveness of the filtration can be compromised. Hence, the continuous movement of air can exacerbate existing dust and air quality issues within the home.

In contrast, the other options do not accurately capture the primary impact of air movement induced by warm-air heating systems. While they may touch on secondary concerns (like drafts or humidity), the main distinction lies in the direct relationship between air circulation and the potential increase in airborne particles that can compromise indoor air quality.