Not all environments are quite as dusty as the next. There are a multitude of factors that play into this, both environmental and human created. Depending on the region in which you live, you could have plenty of dust around your property, or even airborne sand if you actually live in the desert. Mold spores in the air and on the ground outdoors vary to essentially the same degree. Before even looking at human factors, you already have a large amount of change in what affects one area versus another. What makes all of this even worse is when you combine these natural environmental irritants with construction work. You could have ceramic dust in the air if there is concrete being worked on nearby. Likewise, if trees are being cut or wood properties being built, you could have an equal amount of saw dust with natural dust that is rolling around. You can make this worse within the confines of your property by doing laundry more than the next person or something like that. Since my region has all kinds of irritants, I use a quality air purifier to scrub out most of my indoor air before it reaches my Heating and Air Conditioning equipment and moves into the ductwork throughout the property. I will often find lots of particulate building up on the quality air purifier filters as hastily as 3 weeks after replacing them. It’s certainly worth the hassle and the cost, because my asthma issues have been knocked back quite a bit. I can’t imagine residing separate from a quality air purifier now that I’m so used to them. As long as I can afford to buy and replace the filters, I will use the machines for the rest of my days.