Motion Blur
This setting allows you to add motion blur to the particles. When particles are moving really fast, it will provide a smoother look, one that is similar to how a real camera would capture a fast-moving object. Since the shutter stays open for a little while in a real camera, the object moves a little during the frame capture, and this appears as a blur in the direction of motion.
Motion Blur
The options are:
Off - Motion Blur is switched off.
Comp Settings - Motion Blur will use After Effects' Comp Settings. Note that to activate motion blur this way, both the comp's motion blur switch and the layer's motion blur switch must be turned on in the After Effects Timeline window.
On - Motion Blur is on, and After Effects' comp settings will be ignored.
Shutter Angle
Shutter angle defines how long the shutter is open. A value of zero means no motion blur, a value of 180 (the default) simulates a half-second of motion information being recorded on film, and a value of 720 (the maximum) simulates two full seconds of blurring.
Shutter Phase
Defines the phase of the shutter. A phase of 0 means that the shutter is synchronized to the current frame. A negative number will cause motion that occurs before the current frame to be recorded, and positive numbers will cause motion that occurs after the current frame to be recorded. To create motion streaks with the current frame in focus, use a negative phase equal to the shutter angle.
Levels
Defines how many levels of sampling should be used in the motion blur calculation. The faster the motion and higher shutter angle, the more levels you will need to produce a nice smooth blur. Larger values will increase rendering time dramatically.
Opacity Adjust
Boosts or decreases the opacity of motion-blurred particles. An opacity of 100 is the default value, and generates a realistic blur. Increase this value to create unique blurs that seem more prominent than natural motion blur.