This was posted on the “Conservation DistList” which came in today 29th May 2004……it would appear that you are not the only one concerned by airborne particles……
Rgs
Dermot
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“Source Conservation DistList”
Date: 25 May 2004
From: Jean Tetreault <jean_tetreault@pch.gc.ca>
Subject: Air purification systems
Donald Farren <dfarren@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