Effect of barometric pumping on relative humidity in the loessal soil of the loess Plateau

Quantity and spatial distribution of earth-air activity in Cave 108 of the Dunhuang Mogao Grottoes

“…We regard the underground saturated belt as a closed bottom layer, and the ground from the surface to the saturated belt, i.e., the vadose zone, as a closed space covered by the external atmosphere. We can consider earth-air as an ideal gas [ 22 , 23 ]. Therefore, in the process of AP activity, considering the entire vadose zone as a closed space, we can use Boyle's law ( ) to calculate the variable quantity of earth-air as follows: where refers to the amount of earth-air activity ( , where and refer to the volume when the external AP changes from to , respectively), n is the aerated porosity, and t is the thickness of the vadose zone.…”

“…Under the background of AP variation, earth-air activity is widespread on land [ 22 , 23 ]. For cultural relics in caves, the effect of alternating dry and wet conditions of the atmospheric environment can lead to repeated crystallization of salt at the interface of wall paintings, thereby changing the structure of the wall paintings and causing salt-related deterioration [ 24 , 25 ], the most representative example of which is efflorescence [ 26 ].…”