White Paper

Mechanical filters can have a filtration efficiency as high as 100%.
This is for large particles. Efficiency for smaller particles such as
cigarette smoke is usually lower as they can penetrate the filter
media and follow the airflow through the filter and be re-introduced
into the air.
By combining mechanical with electrostatic technology, the filtration
efficiency for smaller particles will increase. When charged particles
come near filter fibers, attraction forces emerge between the par-
ticles and the fibers, making the particles move towards the fibers
and adhere to its surfaces instead of following the airflow stream
around the filter fibers (fig 4).
The result of combining mechanical filtration with electrostatic tech-
nology is an efficiency of 99-100% in capturing particles of all sizes,
both large and small (fig 5).
8. A combined technology
100
0
50
0.1
1
%
µm
0.01
Diffussion
Mechanical
forces
Inertia
Interception
Straining
Total mechanical + electrostatic forces
electrostatic forces
Fig 4 (above)
By combining mechanical technique with electrostatic, charged small particles will be
diverted from the airflow stream with attraction forces. If using only mechanical filter, there
is nothing that obstructs small particles from passing the fiber.
Fig 5 (right)
Straining, inertia, interception and diffusion can be summarized in one mechanical force
as shown by the green curve. Adding electrostatic forces enhance the efficiency to 99-
100 %.
charged particle
attraction forces
uncharged particle