Tenant complains about incense affecting her asthma. Help!

[Aaron Kirby]

We signed a lease for a new tenant on the second floor of a three family. The new tenant likes to burn sage incense. The third floor has asthma and claims that the sage is triggering her asthma and can’t sleep. Third floor would like the second floor to stop using sage, because on the lease it states that we are a smoke free rental property. Is incense considered smoke? Can I legally ask the second floor tenant to stop burning incense, candles, etc. Due to the no smoking policy? The third floor is threatening to make a discrimination claims if I allow the second floor to continue to use her incense. Please help, any thoughts on how to handle this situation...