What is that you are breathing?
If you are concerned about those dust motes in the air that are easily seen floating in sun rays. Or if you get some kind of gritty or fibrous material accumulated on your table or desk every day. Or maybe you have a little coughing fit once in a while. Or an irritated throat. Or itchy skin. Or burning eyes. Or...
Is there something in this dust that you should be worried about? Or if you are having constant or periodic symptoms when in a particular area, could it be something in the dust that is having a detrimental effect on you?
Keep in mind that whatever is in the air eventually falls out of the air. So testing the settled dust for composition can be quite useful.
What can be done to find out if this dust is presenting problems for you?
Building dust has a fairly consistent composition. Variations from this consistency can signal the presence in sufficient quantity to elicit physical reactions. Often up to 50% of dust content is dander. Dander - skin flakes, it can be from humans or animals that stay in the area or occasionally visit. Fibers from cotton or synthetic clothing and paper are often at high percentages in the dust content. So dander, cotton and/or synthetic fibers and paper dust are often among the most plentiful materials.
Many people are allergic to cat or dog dander. It is quite unlikely that people can become allergic to human dander, but allergies to creams, lotions, perfumes, aftershaves and such items that are put on the skin could have allergic effects.
Fungal (mold) spores and hyphae (underlying mold structure), pollens, insect parts, mice and rat dander, urine, feces or hair and dust mite feces and body parts can certainly be allergenic for some people and are often found in settled dust.
Irritants can also result in a variety of physical reactions. Fiberglass, which can come from inside walls, attics or from HVAC systems can be a factor. Fiberglass is known to be irritating to skin, eyes and respiratory system.
A very common irritant is construction dust. It has a similar effect as fiberglass. Where does it come from? Remodeling an area with no or insufficient containment can spread construction dust far and wide. Running an HVAC system while doing such things as cutting drywall or especially sanding the spackling or other such material while running the A/C system can spread the offending material throughout the area served and contaminate the system to the degree that it can have detrimental effects long after the renovation has been forgotten. Often the return vent is covered to keep construction dust from contaminating the HVAC system. That is a good partial solution, but if conditioned air is coming into the remodeling area, it has to go somewhere, so unless the area is placed under negative air pressure and that air safely exhausted, it is likely to travel somewhere that it can cause trouble.
What's to be done?