Fungi and Bacteria Testing
Airfree efficiency in reducing indoor pollution

 

- Page 1 -

REPORT
The efficiency of the Air Sterilizer in reducing the airborne microorganism level in closed rooms at the Biblioteca Nacional (The National Library)

OBJECTIVES
The main objective of this study is to verify the Air Sterilizer effectiveness in reducing the level of airborne bacteria and fungi in closed working rooms. The study evaluates the airborne microbial level of two rooms before and after the use of the air sterilizers.

METHODOLOGY
The test was performed in two rooms of the National Library located at Campo Grande, Lisbon, Portugal.
In room 1 (newspapers room) the newspaper, magazine and book filing place of around 240 m2, 12 Air Sterilizers were plugged in. The other room 2 (Preservation and Restoration Room)

 

- Page 2 -

A 120 m2 area room used specifically for preservation and restoration of bibliographic material.
The test had a 46 day duration. Devices were installed in both rooms on November 24th, 2000 after samples were picked up for analysis. This way the November 20th and 24th samples represent the real airborne microorganism level of both rooms 1 and 2 before the action of the Air Sterilizers.
A Merck MA5 – 100 air sampler was used for the sampling. 4 samples were obtained in roo1 and 3 samples on each sampling day. Each sample represents the level of existing microorganisms in each 100 l of air. The airborne microorganism count was effected in 9 cm diameter Petri dishes.

Culture means utilized in the room airborne microorganism level:
Fungi: Malt Extract Agar (MEA) Dico
Bacteria: Trypona Soya Agar (TSA) Oxoid
Incubation Conditions
Fungi : 25º C 5 to 7 days
Bacteria: 30º C 3 days

Both to fungi and bacteria results were expressed in u.f.c. (colone forming units) per 100 l of air. Each value represents the arithmetic average of the u.f.c.’s of the dishes/ air samples with the same culture means used in each related operation.

 

- Page 3 -

RESULTS
Results obtained for both bacteria and fungi are shown in charts 1 and 2

Chart Legend –
CHART 1 – Air Sterilizer effect in maintaining the microorganism level (bacteria and fungi) existing in room1 (newspaper room). In November 24, 2000 the devices were plugged in. Each point represents the average of 4 counts.

 

- Page 4 -

Chart Legend –
CHART 2 – Air Sterilizer effect in maintaining the microorganism level (bacteria and fungi) existing in room1 (Preservation and Restoration). In November 24, 2000 the devices were plugged in. Each point represents the average of 3 counts.

Observing both Charts it is verified that the Air Sterilizers reduced the ufc/100 l of air, either to bacteria or to fungi although the bacteria reduction was higher.