Hi Dear ! I have gone through your question and i understand your concern I would say that an air purifier will help your air in the room to clear from allergens and other contaminants.especially CO2.These may irritate your lungs and cause pulmonary problems with inflamation.The result is good to have the air clean and avoid other inflamation. .But about if they will help you to avoid totally a new relapse,that is not sure .Cause Sarcoidosis is Your imune system causing the dissease (Lymfocites) and the cause why your system do that is not clear yet.. The relapse of Sarcoidosis may be caused cause of low doses of cortisonic this happens often after you stop the medication for a time or when we low the dosage (from acute dosage to maintance dose 7.5mg). To avoid that if i were you treating doctor if you have another relaps i would consider to start a new drug also called infliximab (imunosupresór drug) for long term therapy it has been shown that has a good effect especially when you have Erithema Nodosus., increase the dosage of Omacortil tp 10-15mg/day . Only your trating doctor can do these changes according to the lung examination and your symptoms Wish these help If you have any other question please feel free to ask me .