| Summary: | 碩士 === 國立臺灣大學 === 環境工程學研究所 === 100 === It has been proved that negative air ions can control the indoor bioaerosols. In addition to renew this technology, in this study, we designed to use a polypropylene non-woven materials(PP-filter) as a wall attached material, and sprayed the bactericidal material–AgNPs/NSP(silver nonoparticles/nonoscale silicate platelets) onto the PP-filter. The PP-filter(AgNPs/NSP or non-AgNPs/NSP) was applied to the inner surface of a test chamber, and the ionizer was kept at 3.1 kV and <0.01 mA. Four bioaerosols－Escherichia coli(E. coli), Bacillus subtilis , Candida famata(C. famata), (B. subtilis) endospores, and the spores of Penicillium citrinum(P. citrinum), were used in this study. Bioaerosols were collected by SKC Biosampler and cultured for plate counts. Besides, we calculated the control efficiency and the enhanced efficiency.
This study which investigated the control efficiency of various treatments on E. coli in decreasing order is treated with the ionizer alone(29.2%), PP-filter attached materials alone(23.7%), and the PP-filter with negative ions (9.7%), PP-filter with AgNPs/NSP (7.7%). However, PP-filter with AgNPs/NSP and the ionizer used did not raise up the efficiency .The results showed the poor efficiency when the PP-filter (AgNPs/NSP or non-AgNPs/NSP) attected in the chamber with the ionizer. We got the great differences in control efficiency of B. subtilis. The results showed the best control efficiency which is about B. subtilis up to 32.2% was treated by negative air ions. This study showed better enhanced efficiency when the same wall material was treated with negative air ions, the enhanced efficiency can be improved to 27.0%; We showed the better control efficiency about C. famata which was treated with PP-filter (AgNPs/NSP or non-AgNPs/NSP) than stainless steel, no matter the ionizer opened or not. The best control efficiency which is up to 31.4% about C. famata was treated with PP-filter (non-AgNPs/NSP),and we had the close control efficiency of other methods, ranging from 18.4% to 24.1%, except PP-filter (AgNPs/NSP). But, if PP-filter (AgNPs/NSP) was used with negative ionizer, than, 20.4%, the higher control efficiency can be obtained; the results indicated that the control efficiency of P. citrinum is between 21.3% and 41.0%, the best is only treated with negative ionizer. We got worse control efficiency when PP-filter (AgNPs/NSP or non- AgNPs/NSP) was used with the negative ionizer than those without negative ionizer. Different from the others ,we had the best control efficiency on C. famata which is treated with PP-filter (non- AgNPs/NSP) without negative air ions.
The following is a summary of our conclusions. The control effectiveness of PP-filter is different to the PP-filter which contains AgNPs/NSP ; the study showed the poor enhanced efficiency when AgNPs/NSP was sprayed on the PP-filter, but if the metods was treated with the negative air ion, the control efficiency could be enhanced(not including E. coli and P. citrinum); when we pasted the same material on the wall, the negative ion ionizer was turned on or not, will affect the control efficiency of bioaerosol (the control efficiency of E.coli and P. citrinum would reduced ,and B. subtilis increased); when the control efficiency of the bioaerosols which were treated with negative air ions is significantly higher than the wall attached material, it was contribute to the enhanced efficiency of negative air ion when the bioaerosols was treated with negative air ion and wall attached material in the chamber (B. subtilis).The control efficiency of the bioaerosols which were controlled by wall attached materials would be affected by higher concentration of negative air ions(it would become a complex situation when negative ions were accumulated to the wall); bioaerosol characteristics affect the control efficiency.
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