|
■ About applications II |
Q1: Could ozone use to treat airborne bacteria?
A1: Yes. The following table shows CT value relates to various airborne bacteria.
|
Microorganisms |
Temp. |
Relative humidity |
CT (ppm x min) |
Survival (%) |
Reference |
|
Aspergillus fumigatus |
-- |
-- |
0.3-0.9 x 240 |
8 |
Dyas et al. (1983) |
|
Aspergillus niger |
-- |
35-76 |
0.1 x 240 = 24 |
84 |
Hibben and Stotzky (1969) |
|
Bacillus cereus |
-- |
95 |
3 x 60 = 180 |
0.013 |
Ishizaki et al. (1986) |
|
Bacillus subtilis |
23℃ |
51 |
0.2 x 720 = 144 |
Nd* |
Klanova and Lajcikova. (2006) |
|
Candida albicans |
23℃ |
51 |
0.2 x 720 = 144 |
Nd* |
Klanova and Lajcikova. (2006) |
|
Escherichia coli |
23℃ |
51 |
0.2 x 720 = 144 |
Nd* |
Klanova and Lajcikova. (2006) |
|
Fusarium oxysporum |
-- |
35-75 |
0.1 x 240 = 24 |
2 |
Hibben and Stotzky (1969) |
|
Penicillium chrysogenum |
-- |
90 |
3-9 x 1380 |
0.1 |
Foarde et al. (1997) |
|
Proteus |
-- |
-- |
0.3-0.9 x 240 |
0.9 |
Dyas et al. (1983) |
|
Pseudomonas aeruginosa |
23℃ |
51 |
0.2 x 720 = 144 |
Nd* |
Klanova and Lajcikova. (2006) |
|
-- |
-- |
0.3-0.9 x 240 |
31 |
Dyas et al. (1983) |
|
|
Rhizopus stolonifer |
-- |
35-77 |
0.1 x 240 = 24 |
43 |
Hibben and Stotzky (1969) |
|
Serratia spp. |
-- |
-- |
0.3-0.9 x 240 |
3.2 |
Dyas et al. (1983) |
|
Staphylococcus aureus |
23℃ |
51 |
0.2 x 720 = 144 |
Nd* |
Klanova and Lajcikova. (2006) |
|
-- |
-- |
0.3-0.9 x 240 |
0.5 |
Dyas et al. (1983) |
|
Streptococcus epidermis |
-- |
-- |
0.6 x 4 = 2.4 |
0.6 |
Kowalski et al. (1998) |
Streptococcus salivarius |
-- |
60-75 |
0.6 x 100 = 60 |
2 |
Elford and van de Eude (1942) |
|
PX174 (virus) |
-- |
-- |
0.4 x 8 = 3.2 |
0.01 |
Kowalski et al. (1998) |
The conclusions of Mr. David P. Chynoweth's presentation "Influence of Ozone Air Treatment on Growth of Bacteria and
Fungi in Air Conditioning Systems" indicates the following results:
I. Concentration of 0.0044 mg/l, duration of 30 min and frequency of 2 times per day prevented visible accumulation of microbial
biofilm in an A/C unit over a period of six month.
II. Concentration of 0.0044 mg/l, duration of 120 min and frequency of 2 times per day resulted in total inhibition of Serratia and
partial inhibition of Aspergillus .
III. Concentration of 0.018 mg/l, duration of 15 min and frequency of 24 times per day resulted in total inhibition of Serratia and
Aspergillus.
IV. Concentration of 0.018 mg/l, duration of 15 min and frequency of 6 times per day resulted in total inhibition of natural
airborne organisms.
(Mr. David P. Chynoweth: Agricultural and Biological Engineering Dept. University of Florida, Gainesville, FL)
Reference
Dyas, A., B. J. Boughton and B. C. Das. 1983. Ozone killing action against bacterial and fungal species; microbiological testing of
a domestic ozone generator. J. Clin. Path. 36: 1102-1104.
Elford, W. J. and J. van de Eude. 1942. An investigation of the merits of ozone as an aerial disinfectant. J. Hygiene 42: 240-265.
Foarde, K. K., D. W. VanOsdell and R. S. Steiber. 1997. Investigation of gas-phase ozone as a potential biocide. Appl. Occup.
Environ. Hyg. 12: 535-541.
Hibben, C. R. and G. Stotzky. 1969. Effects of ozone on thegermination of fungus spores. Can. J. Microbiol. 15: 1187-1196.
Ishizaki, K., N. Shinriki and H. Matsuyama. 1986. Inactivation of Bacillus spores by gaseous ozone. J. Appl. Act. 60: 67-72.
Klanova K. and A. Lajcikova. 2006. Use of ozone to reduce Bacteria and Moulds in the air and on surface. Indoor Built Environ
15-1: 81-84.
Kowalski, W. J., W. P. Bahnfleth and T. S. Whittam. 1998. Bactericidal effects of high airborne ozone concentrations on Escherichiacoli and Staphylococcus aureus. Ozone Science and Engineering 20: 205-221.