I read your comment with interest. I am an asthma sufferer - it’s not as bad as many in fact not at all serious. Nevertheless it is given as a chronic condition. In our bedroom my wife and I have a Hepa air filter with ioniser. Prior to owning and using this I used inhalers every night and every morning. My breathing was laboured and uncomfortable. I used to have a cough too. We now operate this unit every night. I no longer use the inhalers or cough. My non asthmatic wife even notices the difference in air quality. She no longer snores - a bonus I can assure you. If we forget to switch it on one of us wakes up with breathing discomfort. It is switched on straight away. We have a spare one too that we have lent to friends. They too have noticed the improvemnet in air quality and their sleep. Proof of the pudding is in the eating - not in clever semantics. Sleep well…