There is fog in Hefei

Frost is a solid, which is formed by the heat release of water vapor in the air and belongs to sublimation phenomenon; Sprinkling salt in ice and snow can make the ice and snow melt quickly, because the melting point of ice decreases after adding salt, and the ice and snow can melt below 0℃.

So, the answer is: Ninghua; Release; Reduce the melting point of snow.