How did the dry desert air help preserve the Mogao Caves?

The Mogao Caves complex, located near the city of Dunhuang in China, has been exceptionally well preserved due to the arid desert air of the region.1

This dry environment is characterized by a significant shortage of moisture, low atmospheric humidity, and high potential evaporation rates, which prevent the accumulation of water that would otherwise damage the site's delicate structures. Because the caves are situated in a region where precipitation is minimal and the air remains consistently dry, the fresco paintings, clay sculptures, and ancient manuscripts housed within the complex have remained in a remarkable state of preservation for centuries. This unique climatic condition has allowed the quality and quantity of the artistic and textual treasures at the site to remain unmatched, protecting them from the decay that moisture and humidity typically cause in other environments.231