Coughing a lot more indoors?

what is an air quality monitor? I never heard of that but it sounds useful.

It monitors CO2 (& a couple toxins). Poor circulation shows up w high CO2. I can't say if what it monitors directly contributes to bronchiectasis:
5-in-1 Professional Indoor Air Quality Monitor Indoor Portable CO2 Monitor | Temperature | Formaldehyde Detector | Humidity TVOC | Air Quality Tester - Confined Space Clean Air Monitor https://a.co/d/afy74if

We have a Coway air purifier and have liked it. It's very quiet. We bought it based on reviews in Wirecutter. Hard to know exactly how well any of them work but ironically the only time it kicks into overdrive is when I nebulize!

The one linked below is the one we have in our bedroom but there are many different sizes based on the square footage of the area you're trying to cover

Coway: https://cowaymega.com/products/mighty-ap-1512hh
Wirecutter Reviews: https://www.nytimes.com/wirecutter/reviews/best-air-purifier/

Thank you! I have seen some bronchiectasis sites recommending to use air
purifiers. Does anyone know if there is an issue with the filters harboring
& dispersing MAC or other bacteria we would be vulnerable to?

I can't say 100% whether the air purifier captures everything but it has to be better than breathing the unfiltered air. There is a HEPA filter at work on the Coway purifiers.

This is directly from their site re: filtering

True HEPA Filter
Captures ultra fine particles like viruses and bacteria
This one-of-a-kind filter captures an incredible 99.97%² of ultra fine particles like viruses, bacteria, fungi and pollen, and includes an antimicrobial treatment to deactivate the spread of contaminants.

I run three air purifers in our main living area. They are made by Fellowes and have used them for years. I want to get updated models but they all still work. All have carbon and hepa filters. In the bedroom have a small IQ air desk size, very pricey but I can take it when we travel. They all are definitely getting dirt and pet hair out of the rooms. Can tell when you clean them.
We live in a wildfire area and even when air quality was in the 2-300 you couldn't smell smoke in the house.

We use Honeywell 2 stage air purifiers, a large one in the living room & a smaller one in our bedroom. They use a prefilter that catches odors, most dust and pet hair, and separate HEPA filters for small particulates. This is in addition to a whole house HEPA system on our HVAC. We have a smaller one in our tiny house in Texas, and will be purchasing one for our camper yet this fall.
I read all the reviews before I bought, concluded that most of the good filters were very closely matched in their ability to trap pollution, and chose the Honeywell for 2 very pragmatic reasons - they have been around forever and use standardized filter - so are readily available in a multipack. And they have signal lights that tell me when to change them. Even though the prefilters are supposed to be good for 3 months, I usually need to change them more often.
My kids each bought top-rated HEPA filters from new manufacturers a few years ago, and both companies are gone. When they use up their current supply of filters, they will need to buy new machines. And one has a pre-filter that requires weekly vacuuming - no way I want to be exposing myself to that.

The 99.97% HEPA filters, not matter the brand, should capture NTM and just about every other bacteria, not pass it through.

When it is time to change the filters, I mask up, take a bag to the machine, drop in the old filters and tie it shut. That minimizes exposure, and any chance of shaking contaminants loose around the house.

which model Honeywell is that Sue? Do you leave it running all the time?? I have a Honeywell but rarely use it for some stupid reason! It is kind of large and takes up room if that is an excuse.

Yes they do take some space but even in my tiny house (400sf) it is worthwhile. Especially after kids and pets have been running through the house, and I can see all the big stuff the outer filter caught!
I have the Honeywell Insight Series, Models 5220, 5250(I think) and 5550. I turn them off if we are going to be away for more than a few days, otherwise they are always on. The largest one automatically turns itself up if the air quality is poor - if it does that and I'm not cooking, I know the outside air quality is poor and close up the house.

I also can tell you that when I run them, I have to dust my house less, so I view it as an "energy saving device"😉

I’ve been happy with my Winix Air Purifiers model number 5500–2. They come with a HEPA filter, pellet charcoal filter, and a pre-filter that needs to be vacuumed every two weeks. As Sue pointed out, Air Purifiers with HEPA filters are remarkable for reducing dust in the living space. The Winix is available at Costco under the model number Winix C909 4-Stage Air Purifier with Wi-Fi & PlasmaWave Technology. The plasma wave is basically ionization, which is not good to run, but can be turned off easily on these models.

If you’re concerned about VOCs in addition to dust, then consider IQ air or Austin. They’re quite a bit more expensive but they are very effective in removing volatile organic compounds, which include wildfire smoke, cooking smells, etc.
https://austinair.com/
https://www.iqair.com/us/