Reduction of airborne bacteria in hospital using electronic air purifier with and without photocatalysis reactions

Abstract

In this study, an electronic air purifier was used with the principle that particles are charged and migrate to the receiving filter which has lower electrical potential. Thus, the particles can be separated from the air stream. The electronic air purifier was placed in the waiting area of the OPD and burn unit in Srinagarind hospital. The total airborne bacteria samplings were conducted before, during, and after the operation of the air purifier at the distances of 0.5, 1 and 2 m from the air purifier. The photocatalysis study was also performed by coating the receiving filter of the air purifier with titanium dioxide and filled it back to the air purifier unit. By using black light lamps irradiating onto the filter surface, the photocatalysis reactions were provoked; and the airborne bacterial samplings were performed in the same manner as indicated above. The results showed that with the photocatalysis, the effectiveness of air purifier was improved especially in the non-crowded area. The highest bacteria reduction from photocatalysis at a distance of 0.5 m at the OPD waiting area was 59 % in the first run and 73% in the second run (average of 53% from a 50-min operation both runs, morning section and afternoon section). The highest bacteria reduction at the Burn unit was 82% in the first run and 83% in the second run with the average of 58 % from a 50-min operation in both runs, during visiting time and not visiting time. However, without the photocatalysis, an electronic air purifier could reduce the airborne bacteria at the same distance for the highest as 34-40 % from two runs at the OPD’s waiting area (average of 22 %). In the Burn unit, the air purifier without photocatalysis revealed the highest reduction as 35-64 % from two runs with the average of 33%. The farther from the air purifier, the less effectiveness was found.

Keywords:  Airborne microorganism removal, Air purifier, Airborne bacteria in hospital, Photocatalysis,

                    Titanium dioxide