Thanks to both of you - I'll investigate them.
I had a scare last night. Several years ago I developed a serious immune reaction to bird dander. (I had pet parakeets, finches, and a dove.) My lungs became seriously inflamed and my 02 levels dropped to the point that they were about to have me on oxygen round-the-clock. I was so weak I'd be exhausted just trying to get around in my own home. They put me on massive doses of steroids, which brought the inflammation under control, but that wreaked havoc on other body bits. It did make it possible for me to breathe. They told me I had a 75% chance I'd make it five years, if the meds hadn't worked. Took me the better part of a year to get weaned off the steroids, had to give up my beloved pets, and had to move to an apartment that had no latent bird dander in it. (Tried painting the bedroom and replacing the carpet, but needed more.) But things settled down - I just have to avoid bird dander. So, holding my breath when in pet stores that have budgies, that sort of thing. Other than that, I now and then have a bout of hayfever that I use an antihistamine for and life goes on.
Anyway, last night I woke up in the middle of the night having a hell of a time breathing, just as before. We'd been vacuuming most of the day, and tidying up the Daughter's incredibly dusty (she's not a neat-freak) bedroom. The Vax hepa-filter vacuum did a great job, but there's still dust in there on the book cases and dresser. I had no problems all day. (I'd also put a kerchief around my face to kind of try to help, just in case.) But, after all that, late in the evening she put on an oil diffuser with a new essential oil (Neroli?) It smelled nice.
I went to bed, and a couple of hours later woke up coughing and then couldn't breathe. Had to have her shut it off, opened the windows to my bedroom and stuck my head out into the "fresh" air, and almost immediately got a lot better. Spent the night with my bedroom door closed and the windows wide open.
Doing ok today, other than that I've got a slight wheeze on exhalation (very familiar with that) that I'm monitoring, my 02 levels are in the low 90s (which is acceptable) and have had a chat with the Daughter about not running the diffuser so much. Went ahead and ordered a hepa-filter purifier off of Amazon, a relatively cheap one, to hold me over until I can source something more powerful.
Interesting that the Neroli set it off. Or perhaps just the combination of pollen, then house-dust, and then the Neroli. She's used other diffuser oils in the past that have not caused me any trouble, and I used to have Neroli and Patchouli oils around when I was a teen. Oh, well. Better now, and will be very happy to have a hepa air-purifier in the house anyway.