Around smokers- Unsafe?

Rabia • Expecting our first child! Extraverted mom, introvert dad. Baby? No idea! :D
Hi, my boss is a chain smoker and sits right next to me. She goes for a smoke and comes back and the smell is annoying. I feel my lungs secrete more mucous in response to it and it is suffocating. I don't feel like working with her anymore. How do I deal with this?