Air purification systems

Donald Farren <dfarren [at] concentric__net> writes

>Does anyone have experience with relatively small, free-standing air
>cleaners (of the sort that Sears sells)? They are advertised as
>"99.97% effective in removing most airborne particles, including
>pollen, smoke, mold spores, and pet dander". Question: How effective
>are they in trapping fine dust particles, like "book dust"?

Filters having efficiency of 99.97% are designated as HEPA (High
Efficiency Particulate Air) filters. They will trap almost
everything having a diameter equal or bigger than 0.3 micrometer.
For particles having a diameter lower than 0.3 micrometer, they will
be still very well trapped too (> 90%). However, you have to realize
that you will be in competitive mode between, particles that the air
cleaner can catch and the particles that can be deposited into your
collection without been trapped by the cleaner. Obviously, it will
reduce the dust deposition on your collection. Big lints from staff
and visitors may still fall down the floor without been captured by
the air cleaner. Airtightness of the room, ventilation power of the
air cleaner and the size of the room are parameters that will affect
the efficiency of the air cleaner. More detail can be found on the
book: "Airborne Pollutants in Museums, Galleries and Archives: Risk
Assessment, Control Strategies and Preservation Management." For
more information on this book see
<URL:http://www.cci-icc.gc.ca/links/pollutants/index_e.shtml>

Jean Tetreault
Senior Conservation Scientist
Canadian Conservation Institute
1030 Innes Road Ottawa
Ontario K1A 0M5, Canada


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                  Conservation DistList Instance 17:71
                   Distributed: Friday, May 28, 2004
                       Message Id: cdl-17-71-001
                                  ***