The spread of small particles in interiors is determined by the movement of the air. Already without additional ventilation, the thermic convection is enough to cause a circulation of the air in a space. This leads to a proportionate distribution of the fungus-spores, also between different spaces and floors. So, one gram can contain house dust up to 3,2 million living fungus-spores. So Cladosporium-Arten dominate in the outside-air and as typical "space-fungi" occur the types of the kind Aspergillus and Penicillium, that on foodstuffs, moist leather, paper, cotton and wool grows. Also Alternaria, Aureobasidium, Fusarium and Wallemia sebi are demonstrable besides it. (Cases in point picture 4.1. and 4.2.)
Form 4.1. and 4.2.: Penicillium-Arten for greenish and Fusarium roseum for the ginger spots. Links to a wood-disguise (heat-bridge and lacking rear-ventilation) and right on a wallpaper after a water pipe-damage in the space and lacking ventilation. These ginger spots were found by the real house-sponge (Serpula lacrimans) also already with the existence. So, a mold-fight (any poisons) was carried out instead of a sponge-financial recovery.
Kitchens: In refrigerators, Penicillium roqueforti is at bread-shearers, on moldy bread as well as over trash cans to be found.
Toilets and baths: With temperatures, over 24 °C can over the mats before toilet-bowls Aspergillus flavus in the ambient air and A. parasiticus appear.
Living rooms: The palpitation of the floor-coverings leads to a firm increase of the bacterial counts. So, Aspergillus vericolor and Cladosporium sphaerospermum were found mainly in Belgium in 130 living rooms.
Schlafzimmer:Der mattress-dust contains rather uniformly composite xerophile (loving dryness) mold-flora: Eurotium prevail, Aspergillus repens and A. penicilloides. In the bedroom-air, the highest bacterial count occurs caused by the heater in November and December. The mattress-dust gains the maximum in July. This is based on the elevated relative atmospheric humidity (70-80%). Always lead the Bettenmachen to a clear increase of the spore-number in the air as well.
Swimming pools and saunas: The molds are evenly distributed on changing rooms, swimming-area, shower and WCs. The floors are the most strongly attacked. In the Marburg, the salespersons of the Dematiceae (fungi imperfecti with dark spores and/or Hypen) especially frequently were determined.
School-spaces: Studies at US-American schools showed air-germ contents in the area 100-15.000 spores / m³. The salespersons of the kind Cladosporium participated the most frequent present.
Hospitals: Spores of the outside-air reach into hospitals regularly and can lead to a distinctive mold-growth there. (So, one found thermo-tolerant penicillin in a treatment room in the USA.)
Bio-tons: if interiors are particular Art, who is protected before the germ-hindering UV-Strahlen. With the contact with Biomüll, mold-spores reach inevitably into the surrounding air and from there through inhaling also in the human body. Can so A. fumigatus for people with reduced immune-resistance as consequence of a chronic reason-illness very dangerous becomes and too mortally proceeding invasive aspergillosis leads. Therefore, resistance-weakened people should avoid the contact and the contact with bio-refuse. Little one portion-wise package into newspaper as well as a rectification of the ton with vinegar-water and positioning in a shady place clearly reduces the spore-share. The collection should not exceed 1 weeks. 
Everyone knows moldy bread and white, how fast this straight one in the summer and can mold above all at muggy-warm. Foodstuffs and straight pasta virtually represent an optimal food-basis. Therefore, formulas are admitted, that make a certain durability possible. I now had to determine twice that the rolls and the bread had molded already after 4 and 5 days respectively. During this time, the temperature lay zw in the kitchen. 23 to 25 ºC and the relative Humidity was between 40 to 63 per cent. The humidity in the building lay far below the growth-border, as it in the Isoplethensysteme in the picture 2.1. or 2.2. it is represented where a mold-formation (theoretical) can take place. Decumbences determined optimal growth-conditions for microorganisms before, so these also grow with a relative humidity > 70 per cent. The cause should be substantiating in it that all influential factors and her/its/their mutual interrelationships are not adequately known. If certain border-areas already were reached, so the additional small flowerpot can cause the optically visible mold-affection, for example. The cause now is not the small flowerpot but the sum from the many individual influential factors.
That actually is the reason why no mold-affection is visible in 9 out of 10 same apartments. Even if 1 m² wall-plains molded in the tenth apartment, the concentration of the fungus-parts can be more inferior altogether, as in the remaining 9 apartments, where nothing visible is optically.
The argument, if molds exist visibly in the apartment, is aired "too few or wrong for" it, should be used really only under exception clause.
There is of course, the user's life-content virtually passes also exceptions, where one can assume, to breed large volumes of microorganisms in the apartment.