When is use this set-up at night I smell an obnoxious odor. I never smelled this when using oxygen at a hospital. I find the odor remains in my nostrils & or sinuses during the day. I've ask my medical device supplier and my pulmonary doctor and all I get for an answer is "Am I cleaning and replacing my filters". Yes I do take care of the filters but what is this lingering odor and is it detrimental?