When is sunlight dangerous for masks?

I have a habit of taking a mask out of my case and keeping it on my coffee table so I can gush over it all day. However, this is also right next to the north-facing sliding glass door to the patio (apartment). I get concerned as it is hit by sunlight, but only indirectly, and glass tends to block most of the UV

Should I protect it more? Is it fine as-is?

Direct sunlight, dont leave it outside or sitting near an open window or the mask will turn yellow and dry out over time