It is a standard protocol followed by Industry to use 90 Degrees Elbows for all types of piping applications. Whereas it does not look wrong to use this fitting, but a potential pressure drop point is created every time the gas passes by this fitting.

A better alternate is to use two numbers of 45 degrees elbows in tandem as shown in the image which achieves a better result over a 90 degree elbow. PNEUMSYS offers these elbows from Eqo Fluids which are available in all sizes from 20 mm to 63 mm.