My neighbor smokes in the hallway

She smokes in the hallway, two apartments down from mine. How do I ask her to smoke somewhere else? I'm worried about my baby's health. I dont think there's a smoking policy in our leases, but I'm not sure, I highly doubt it. It's an old building and we've lived here for many years. Everyone does what they want. many neighbors smoke outside, in their balconies, in the parking lots, and this lady smokes in the hallway. She's the only one. The manager doesn't care. It's really annoying and infuriating quite frankly.

How do I ask nicely?

We're planning on moving for my baby's health.