The issue in drinking bottles is that the water is sitting in the bottle for a long period, having a lot of contact time with the plastic, which leaches BPA into the water.

BPA does not particularly emit vapors into the air from polycarbonate, it's a contact issue.

This mat should be fine. The only caution I would give you is to not walk on it with bare feet and especially don't have bare feet sitting on the mat for hours on end while you are working at the desk. Any plastic can be absorbed through the skin by contact, especially long period of contact where heat and moisture from your feet can increase leaching.