Why are my rendering blurry on iOS?

My icons are sharp and clear on the emulator, but when it gets onto my iPhone it became blurry like those compression you see for JPEG.

What should I try to make it as clear as inside the emulator?

Make sure that you have your quality settings set correct.
You might have the the default quality for ios lower then you are previewing it inside the editor.
Lower quality settings have a option enabled that will reduce the texture resolution.

Secondly check the compression if your sprites, you might want to turn the compression of your sprite off.