Would be grateful for any recommendation for an air purifier for a bedroom. I regularly get some sort of allergic reaction which follows the same course, manic bout of sneezing followed by two or three days of feeling really rough and tight chest, puts me out of action which is really irritating. Doing a fair bit of work at the moment upstairs, two bathrooms and three bedrooms and it is generating dust, unsurprisingly. Just want to give one a try to see if it makes any difference when I am sleeping, don't particularly want to spend hundreds on a Dyson or similar.
You need an electrostatic air purifier that produced a high voltage and then uses this to charge the dust particles. They are then attracted to the wires in the unit and stick to them. Clean by brushing the wires with a vac.
Was in a similar situation. House was getting plastered, rewired, floors fitted, etc. Big dusty mess. I got "HoMedics True HEPA Air Purifier". It helped make the air less dusty. As you can expect, these things aren't designed to clean up polluted building sites Floors and surfaces will still be dusty but at least they can suck out dust in the air. The one I got had different levels. The lowest had a soft enough sound to be left operating overnight in the bedroom. I pretty much had it working 24 hours. Cleanable too. https://www.amazon.co.uk/HoMedics-Purifier-Eliminates-Allergens-Foundation/dp/B006ZKXIXK Note on Amazon: This device was 67 quid when I got it 5 years ago. It now shows as 75 quid (reduced price from 99!). I strongly recommend checking price history on camelcamel before you buy anything from Amazon.
Some have mentioned an ioniser. Bad idea. These can make breathing worse and they attract dust. In my case as an asthmatic I binned my ioniser. I bought a Vax 200 filter. This has a night mode so it should be OK in your bedroom. My breathing is sooooo much better now. The Vax has a 360 degree filter so works from all directions.
I bought this one as it was only £45. It has the ionizer option but you can also turn that function off if you wish. It seems to have done the trick for my hay fever as I wasn't going to pay Dyson money!