We've been advised by our tape library vendor that one of the reasons we might be seeing lots of errors is if our server room is particularly dusty.
It doesn't look dusty, but that's not to say it's not there.
We've got an environment sensor cluster which measures Temperature, Airflow and Relative Humidity.
I should probably point out that the low-hanging fruit solution I came up with is to use Sellotape (scotch tape) in a loop, one side stuck to the server cabinet, the other side free-hanging. I've also put a couple of other tape loops by the exit and intake fans of the hardware (not blocking airflow, naturally).
How can we (electronically, ideally) measure dust levels?