Xbox one smallest particles or sand in ventilation?

I own an Xbox one and this is above the ventilation shaft and I think when I cleaned my screen of dust, a few or a grain or sand grain fell in there. If I lift up the console and turn left and right in the air and listen carefully, I sometimes hear a very slight rustling of probably one of those grains… Could that be a problem?

It may be one, but rather less

What can it possibly be?