The area I live in has a regulation that people should wear PPE when visiting grocery stores, etc. There is a shortage of PPE. I have access to some non-reusable FFP2-class respirators that are intended to be used during a 8 hours shift (similar to this one). Reuse of disposable respirators has been suggested as a crisis measure during the shortage. I have been reusing my respirators for a while, but by now I have used each of them for more than 8 hours.
Until I can replenish my stock, I have a choice between using the repsirators beyond the designated 8 hours, or resort to cloth masks, which are widely available / widely used in my area. A cloth mask is basically nothing more than a piece of cloth that can be attached to one's face.
My research so far
I'm by no means an expert, so correct me if I'm wrong. From what I understand cloth masks offer almost no protection against viruses. Respirators, on the other hand, offer some degree of protection due to being able to filter out particles/droplets from the inhaled air thanks to the electrostatic charge of the filter material. However, I wasn't able to find any info on the following:
What happens to the respirator during the prolonged use?
Why is the use time limited? Is it because the contamination of filter layers reduces the electrostatic charge?
Most importantly, can a respirator at some point become less useful / more harmful than a cloth mask? (assuming that the user knows how to don/doff and store the respirators properly).