Particle emission grouping together

As you can see in the image particles are grouped together/overlaying each other. Any help in creating a smoother effect would be great, thanks!

Your Unity editor appears to be 5.4. If you don’t want to make a huge leap of updating the engine, check the exact version of your Unity and look for the latest patch or final release of 5.4 (Unity occasionally forgets to address the fix in the release note). Otherwise you should consider upgrading to 5.5 or 5.6 because fixes of many 5.4 bugs are only available in 5.5 and onward without backporting.