how to change post processing effect in 2D?

hello! so i have this 2D project where when a specific gameobject (like a wall or a giant portal) reach a certain distance with the player the post processing effect will change from a happy bright vibe to a very dark grim effect, thing is ive already set up the post processing effect for the whole scene but i have no idea how i can change the effect when (said gameObject) reach a certain point towards the player, does anyone have any tips or ideas on how i can change it?