Where Can I find a HEPA air purifier that doesn't emit ozone?
I have researched different filtration systems and I believe that some of them may still emit ozone even though they don’t specifically say. Has anyone used a particular one with an Umbrella Cockatoo and/or a Severe Macaw? This is a serious matter to me because I have asthma and I love my birds, so please, no puns or jokes. Thank you.

If you’re really concern about the side-effect of an air purifier to your birds, check out the one made by Allerair. All materials used to built the machine are safe even for people/animals that are highly sensitive.
However, I’d also suggest IQAir HealthPro Plus as these machines are the only air purifiers used by HongKong hospitals during the SARS epidemic.
Not only will it filter the air, but it’s odor control is quite good (considering that you may want to minimise odors from bird dropping too.). It’d also be able to control powder dust that your cockatoos emit (better than most air purifiers).
HEPA air purifiers shouldn’t emit ozones. However, some manufaturers use HEPA and ionization to filter the air. Such machines could emit ozones.
So, just look for pure HEPA machines like the above.
I don’t have those lovely birds but I hope my info would help you minimise your asthma problems and won’t endanger your intelligent birds too.
Hope it helps!