The name is due to the double function performed by the component:
particle filter and anti-odour filter.
They are made ,by coupling to a filter element similar to the particle filter,
a second grains support element “Active Carbon “. The last one absorbs,
inside the grains, a part of the exhaust gas components to which
the man’s nose mucous membranes are particularly sensitive. Similarly
to particle filters, the characteristics of the filtering elements determine
a different filtration efficiency, with the possibility of removing dust particles
of different sizes (generally up to the size of a few tens of microns),
allergen agents (pollen or similar substances) and odors generated by
chemical substances of different origin (the exhaust gas of engines, industrial
smokes...).