Back to Jon's original question. Yes harm can be done if pressures aren't right. To high and the extra air hits resepters that tells the brain that you have plenty of air and don't need to breathe. not good. If the pressures are to low your airway isn't being supported well enough and you still have excessive apnic events.
I been on CPAP for almost 10 years and a sleep tech. I hear these stories all the time. Your humidity is to personal preference. Not dry and you sneeze and not too wet that you have rain out. Congestion is usually from a leak. Yes there are hypo filters that will remove allergens and dust. The thing that is most important is a mask that not only fits you, but your style of sleep and need. If you can't contain the leak you need a different mask or mask style. There are at least 100 different masks to choose from, so don't hesitate to ask for a better fit. The fit should be snug but not to tight. There is relief from sinus conditions and other health problems, but it takes time. Don't think of this as a way for better sleep that's a side affect and shows you have adjusted well to CPAP. Sleep Apnea can lead to stoke, hypertension, and diabetes are the biggies. Each apnic event sends adrenaline to the body that is toxic to your health. Did give up on the therapy. It took me over a month to be able to wear the mask one full night, but 3 years later I was able to discontinue all my asthma medications and inhailer. No more headaches, no more naps. I wake up ready for my full day. You have to be patient ask questions there are ways to help make this work for you just stay in the game. You didn't get to were you are over night so don't expect instant results. This is a fiscal issue of airway collapse and XPAP is the best way to control the apnic events.
