Everyone has different standards for their health, but I would not personally consider this sufficient for working with oil-based polyurethane. It does not mention "organic" vapors or "VOC" (volitile organic compounds) anywhere on the packaging. The activated carbon might help with odors, but it hasn't been certified to do anything for your health.
The key thing that you need is the "P" rating (i.e. "P95" or "P100"), which indicates that it is reusable (up to 40 hours) for VOC environments. "N" rated masks/cartridges are for dust only, and "R" rated are for VOC environments up to 8 hours. The number (95 or 100) indicates what percentage of the hazard they can filter out.
You'll also need to make sure that your respirator is the right size, is adjusted correctly, that you do not have facial hair that interferes with the seal, that it is in good repair (i.e. the valves close), and that the cartridges are changed per schedule.