There are many studies produced for salt therapy and many new studies being developed now.
The effect of salt chamber treatment on bronchial hyper responsiveness in asthmatics
Halotherapy in Patients With Cystic Fibrosis
Mucus Clearance and Lung Function in Cystic Fibrosis with Hypertonic
Mechanisms of Halotherapy, Speleotherapy, and Salt Therapy Explained: A Better Breathing Guide
Double blind placebo-controlled randomized clinical trial