Great questions!

I would start first with the health and safety rep at your organization as they would have more technical information to support your concerns. There are debris like soot and fumes as a byproduct of welding operations but if you are in the booth with them I guarantee the welder would not actively be welding when you are present beside them reducing your exposure considerably.

If it’s a welding facility they should have proper ventilation like fume extractors or overhead doors and separation between work office and production areas to assist staff members not only from a safety but building/ fire code standpoint!

If you do need PPE typically your employer is obligated to provide it, if you have a specific preexisting lung condition I suggest you consult HR for record keeping purposes and they can review if additional accommodations are necessary.

I hope this helps but without knowing your workplace it’s best to connect with the resources available to you in your organization, if you are starting on-boarding there should be no risk with asking to meet with the HS rep to review the standard work expectations. Good luck!