A commonly heard statement here on the forum is: humidity is affecting every not hermetically closed device and has influence on the measurements. These are long term effects and are often seasonal. The effects have an influence from sub-PPM to PPM level and take days to become apparent.
The problem is that, besides of some LS8 packages, it becomes more and more difficult to obtain TO-XX or ceramic (which are not moisture sensitive) package variants, instead of epoxy or plastic (which are moisture sensitive), of accuracy determining components.
It is being advised, once in a while, to drop a sachet of silica-gel into an enclosure, but without real explanation
I stumbled on a report from the museum world, a lot of museum artifacts, shown in display cases, are also very sensitive to moisture. This 2001 report of an experiment in the museum world is a very educative writing on the usage of silica gel to stabilize humidity:
https://cool.conservation-us.org/waac/wn/wn23/wn23-2/wn23-206.htmlFor all the "lazy" readers: if an enclosure has minimum air leakage (less than one air change per day), the RH fluctuation can be held within a few percent, by dropping app. 30 grams per dm
3 of silica gel into the box.
This was tested for "big" museum cases, but I see no reason this not to be applicable for smaller electronic enclosures.
This would indeed prove the effectiveness of moisture regulation by silica gel sachets, what do you think?