Standing fan making static noise?

Hi guys/girls.

I noticed when having my fan on, it is making a sort of static noise now and again but not all the time. Only way I can describe it is like the old glass TV's (childhood) when you ran your finger across the screen after turning it on/off and you used to get the static feeling/sound.

It has a bit of dust on the fan blades I was thinking that might be why.

It's not coming from inside the fan where the motor is, it sounds like it's coming from the fan blades of even the metal covering.

Is it possible that the dust can be the cause of static sound while it's turned on?