We spend most of our lives indoors. In fact, more than half of your body's air intake will likely be from inside your home. Research shows that indoor air quality is typically far worse on the inside than the outside, and can actually represent a public health risk. This has become the case ever since energy costs skyrocketed in the 70’s. Our buildings and homes now have less fresh air ventilation than in the past.
Household dust is in every home, and it's components are not just dirt. Household dust is made up from a hodgepodge of human skin cells, pet hair, insect parts, pollen, drywall powder, carpet fibers, insulation, soil particles, bacteria, mold, fungi, chemical compounds from cleaners, sanitizers and insecticides; the list goes on.
For most, household dust is not much more than just a nuisance, but for some it can contain powerful allergic triggers. Itchy eyes, runny noses, headaches and even long term health issues can be the result of extended exposure to toxic household dust. It is definitely a hygienic factor in the home and can also affect the odor of a home.
The actual composition of household dust, including it’s bacterial community, is determined by the occupants of the house. The mix of occupants, pets vs people, the mix between male and female occupants, the age of the occupants, and of course, how the house is cleaned and maintained. All of these conditions factor in to the composition of household dust.