Air handling systems

I am looking for information on equipment for cleaning or filtering air
in library and archival storage areas?  I am particularly wondering
about the (in)advisability of certain sorts of equipment currently in
the general market like deionizer air cleaners. (These devices make me
very uneasy.) I am working with a pre-existing antique HVAC system which
cannot be replaced or modified but which may be supplemented with window
air conditioning.

More generally, I would be interested in messages about experiences with
particular filtering equipment, particularly in dealing with gaseous
pollution.  Thanks in advance.

Paul Romaine
Gilder-Lehrman Library
New York, NY

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                  Conservation DistList Instance 5:44
                  Distributed: Tuesday, March 17, 1992
                        Message Id: cdl-5-44-006
                                  ***