If you are concerned about the Environment, like many, you might want to factor this into your choice of technologies.
Pneumatic Cylinders have been around for a long time and will continue to be used in various applications and there are applications better suited to a Pneumatic Cylinder; however, more and more applications are being solved with Electric Actuators especially Electric Tubular Actuators.
Environmental concerns are just another reason to seriously consider Electric Tubular Actuators.