Fire made by niagara system leek light on the walls that are far away from it

[anonymous_user_ddf1692b]

I made some fire that have different colors(red and blue) to light up my scene,but the blue fire leek their light to some walls that are far away from them,and I don’t know how to solve the problem.
In some particular angle,everything works great,but when I turned my screen a little bit right,the lights of blue fire started to appear on the surface of the walls.

Here’s the map.

And here are the settings of the blue fire.

Thank you for helping!