Air systems treatment guidelines

PATHOGENS IN DETAIL

Mold and fungus

Mold and fungi are mono or multi-cellular organi-

sms that are found almost everywhere: in the soil,

on plants, on animals, in the air and last but not le-

ast, in living and working environments. In buildings

under normal hygienic conditions, where there is no

active growth of fungi, you can count from 3,000 to

10,000 spores per cubic meter in air, with a diame-

ter ranging from 1 to 60 microns. The most common

species recognized in the interior are Cladospo-

rium, Penicillium and Aspergillus, but many others

can also be found. When certain conditions arise,

mold produces a large amount of mycotoxynes whi-

ch, when inhaled, can cause health problems. Moi-

sture is a necessary condition for the germination

of spores and for the continuous growth of fungi.

Many buildings, for various reasons, suffer from

excess moisture and conditions that promote the

proliferation of these agents: in this case, further

spores are produced that are dragged by air move-

ment in the room and tend to colonize other areas.

The development of mold

Conditions that favour, or limit, the development of bacteria, viruses

and various pathologies. As you can see, optimal hygiene conditions

are produced by relative humidity values between 30% and 60%.

Mold spores need a source of food to develop and

multiply. In most cases this food source consists

of wet areas with organic materials of various ori-

gins. When a spore of mold settles in a favourable

environment, the enzymes that make up the outer

surface of it solubilizes and, in doing so, it dissolve

nutrients in close proximity. They are absorbed by

the spore through the membrane that envelops it

Representation of the 4 stages of mold development starting

from the deposit of a spore on a surface that offers the neces-

sary conditions in the form of moisture and organic substan-

ces of various kinds.

due to the osmotic pressure different from the out-

side. Subsequently, the spore to develop the cha-

racteristic strands, they are also covered with en-

zymes, which, in turn, dissolve additional organic

substances and lead to the development of fungi,

which can proceed very quickly if the conditions

are favourable. They produce other spores that are

dragged by air movement into the environment an

tend to colonize other areas. The process is traced

back to four essential phases illustrated in the figu-

re. Within 48-72 hours, colonies of mushrooms can

be produced in the mattresses of the suspended

ceilings or in the partitions made from plasterboard.

Muffe e rischi per la salute

Mold and fungi produce unhealthy conditions in the

spaces and are responsible for bad odour release,

they damage most of the organic substances and

materials, including fabrics, leathers etc. in addition,

of course, to food products. Although most fungi do

not have direct effects on human health, some of

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