Particle systems are great for creating effects such as rain, snow, steam, sparkles, hordes of birds, foot prints, armies of ants, and more. Unity ships with preconfigured particle systems ready to use, and it lets you create your own from scratch. Here, we'll use some premade systems that can be added easily to the scene, for drama and tension. To access the premade systems, import the ParticleSystem package into the project. Choose Assets | Import Package | ParticleSystems from the application menu, if you've not imported the package already. From the Import dialog that appears, accept the default settings and click on the Import button.
Importing Unity particle systems
Once imported, you can access all premade particle systems via the Project panel; through the Standard Assets | ParticleSystems | Prefabs folder.
Access ParticleSystem packages
For our eerie, industrial environment, a steam particle system should work well to simulate steam escaping from broken pipes or...