The airbag light is part of the SRS system and will need to be diagnosed. There is a code stored and the code will have to be retrieved. Once the code is retrieved a diagnosis will have to be done to determine the reason why the light is on.
A failed purge and vent solenoid are parts of the evap system. These parts cannot be repaired, only replaced. It's important to have the system checked by a qualified technician to make sure that these are the faulty parts. The system is complex and while you can run a test with a scanner it only gives a general diagnosis. A qualified technician will be able to test the individual components and repair the problem.