FPS drops when particles are in view

[goatsemeatpie]

First off, my game works fine. I get around 60 FPS inside and 30-40 outside. But whenever something like light shining through a window, fire, or steam gets in my view, my FPS count goes to a crawl, about 10-20 outside and 15-30 inside. Is there anyway to fix this?

 

Specs:

 

Intel Quad Core i5-2320 @ 3.00 GHZ

Geforce GT 620

12 gigs of RAM