See in text (Book the First: Recalled to Life - Chapter IV)
The word choice "damp" refers to both the moisture and cold in the industrial mine. The word creates a somber tone because it has close associations with words like "mildew" and unsanitary working conditions.
"All the air around was so thick and dark..."
See in text (Book the Third: The Track of a Storm - Chapter VII)
The Victorians believed that sickness, as well as general moral corruption, could be transmitted via fog, mist, or clouds. Dickens often uses mist or clouds to foreshadow an impending disaster—in this case, violence and death—and convey a tone of anxiety and apprehension.