on Fiction University:

Your characters’ world provides opportunities to create mood and raise the tension in your scenes.

Universal Studios’ Halloween Horror Nights is a perfect example of how a setting can influence the people in it.

The park is decorated with haunted houses and scary set pieces, and costumed staff (some with chainsaws) lurk in the shadows to jump out at guests. One group is startled and they scream, which makes everyone around them nervous, and just when people start to relax, another staff member leaps out. People who normally wouldn’t be startled tend to shriek, because the setting already has them on edge.

This isn’t a happy coincidence. These staff members are trained to target guests who typically scare the easiest, so they look for younger people (particular teens and women) in groups, because they scream the loudest, and screams are contagious.

Your setting is the “spooky background music” of your novel.