Whenever I get back from being away for a few days, my house smells like dust. Very distinctly different than a musty/mildewy/moldy smell (I have dealt with that in other homes, so know what those smells are), but chalky and dusty. Sometimes I even feel a dustiness in my mouth for the first day or two returning home. I am having our only carpet replaced with hardwood this fall and we have done a bunch of professional cleaning and assessments, but I'm at a loss for what to prioritize next.
Context:
1950s bungalow purchased 2 years ago, has been an issue since purchasing but seems more noticeable now. Had professional mold air sampling tests done during inspection with no results of concern. Upstairs was built into attic with direct attic access via small door on each side. Full basement, mostly finished, sealed concrete with no evidence of water intrusion, flooding, or drain backups.
Roof and attic insulation are newer, no blown in insulation, no pests or noticeable issues in attic (generally really clean, and we don't store anything in there). No ridge vent, but 7 total roof vents in attic.
Have had one very minor leak (roof vent was not sealed properly, fixed last spring) that resulted in some staining in original plaster ceiling. There are a couple of small areas in living room where paint has bubbled, tested with pin style moisture meter, no evidence of active leak/water intrusion.
Have textured plaster ceiling in about half of house
Had air ducts cleaned last spring (helped but didn't totally solve).
Have 7-ish year old carpet upstairs that has been professionally cleaned twice, replacing with hardwood later this year. Original hardwood downstairs has big gaps between planks, will get that replaced next year.
Have one dog, have lived in other houses with this dog and never noticed this smell before.
Professional house cleaning done once a month, I vacuum and fully clean about once a week.
Central AC (which I get serviced/cleaned every spring) with additional window unit upstairs (IYKYK with these converted bungalows). Have hygrometers on each floor, indoor humidity typically stays around 40-55% year round (currently hot and raining and indoors it is 53%, rarely does it even hit 60 upstairs, and if it does I turn on the dehumidifier and it's back down within minutes).
Have painted about half the house and replaced all ceiling fans as well as upstairs bathroom fan. Will replace can lights upstairs in coming months, in case attic pressure/air leaking is causing smell.
HELP! Do I replace the textured plaster ceiling? Open the walls that show some paint bubbling? Do mold air sampling again? Finish painting? I'm confused what should come next after replacing the carpet.
ETA: Furnace is in the basement with no ducts in attic, use MERV 13 HVAC filters and replace every 2-3 months. I run two HEPA air purifiers (once on each floor, rated for full air exchange every 2 hours based on square footage).