Hi Alex,
The Content Examples project has some good particle systems that you can use as a starting point for the air explosion that you want.
You can also find a great set of tutorials for creating your own particle systems here: Introduction to Cascade | v4.2 | Unreal Engine - YouTube
Here are the steps you can take to activate a particle system through matinee:
- In the Required module of your particle system, set Emitter Loops to 1
- Also in the Required module, set Emitter Duration to the amount of time the effect should last after becoming active
- Drag the particle system from the content browser into the level and position it
- In the details panel of the editor, uncheck the Auto Activate property of the particle system
- With the particle system still selected, open matinee
- Right click in the Tracks panel and select Add New Particle Group
- Choose a name for the group and press enter
- Select the particle group track and scrub the timeline to the 45 second mark
- Press enter and select Trigger, then click OK
You can actually trigger the effect multiple times in the same matinee if you so chose.