Airborne Characteristics of Allergy-causing Fungi: Alternaria alternata, Aspergillus versicolor, Botrytis cinerea, Cladosporium herbarum

• Main Authors: Yung-chun Teng, 鄧永俊
• Other Authors: 李書安
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/7fx26n

碩士 === 逢甲大學 === 環境工程與科學學系 === 102 === Fungi in the air is one of the microorganisms in the environment, some of which can cause human respiratory system diseases and produce toxins. Therefore, the study on characteristic of fungal release is particularly important. In this study, we referred to the design of impactor and built an Automated Fungal Particle Aersolizer (AFPA). Based on Aspergillus versicolor, Alternaria alternate, Cladosporium herbarum and Botrytis cinerea, which could potentially cause allergies and respiratory diseases to human, we investigated different environmental factors (wind speed, temperature, humidity and culture time), and investigated the physical characteristics (concentration, particle-size distribution) and biological characteristics (viability, culturability and (1→3)-β-D-glucan) of the fungal particles released in the air. The result reveals that if we use speed 5rpm, the fungal particles will release from the substrate surface and spread evenly in the air, and the centrifugal force generated by rotation will not affect the dispersion. If we increase the wind speed, the fungal particles will release in the air. There’s almost no fungal particle found with indoor wind speed at 0.3 m/s and outdoor wind speed at 1.7 m/s, if any, they are just fungal fragments (<1m). Only when wind speed is greater than 11.6m/s, we can begin to see fungal spores release. Therefore, many of the studies on sick building syndrome are not associated with the fungal spores. Fungal spores won’t release when the indoor wind speed is low, the impact mainly comes from fungal fragments. The culturability of most fungal rises with increasing wind speed. Overall, the concentration of fungal particles released in the air is shown below: Botrytis cinerea > Aspergillus versicolor > Cladosporium herbarum > Alternaria alternate. Aspergillus versicolor and Cladosporium herbarum will release more fungal particles, total fungal spore concentration, total viable fungi concentration and total culturable fungi concentration when the temperature is 4oC and 25oC; Botrytis cinerea will release more fungal particles, total fungal spore concentration, total viable fungi concentration and total culturable fungi concentration when the temperature is 37oC. The temperature will not affect the viability of Aspergillus versicolor, it means Aspergillus versicolor is born with high temperature resistance. Most of the fungal viability will decrease with increasing temperature, which means low temperature can keep their viability. The culturability of most fungi is also better when the temperature is around 4oC and 25o. Aspergillus versicolor, Cladosporium herbarum and Alternaria alternate will release more fungal fragments (<1m) when the humidity is higher. Most of the fungi’s total fungal spore concentration, total viable fungi concentration and total culturable fungi concentration will decrease with increasing incubation humidity. This may be due the following reasons: Moisture in the air condenses on the fungal spores’ surface, increasing their weight; so the amount of release decreases with increasing humidity. Or, maybe high humidity could affect the growth of fungi. Most of the fungal viability will decrease with increasing humidity; it means dry environments can keep their viability. The culturability of most fungi is better when RH = 45%. Aspergillus versicolor and Cladosporium herbarum’s quantity of (1→3)-β-D-glucan will decrease with increasing incubation humidity. While that of Botrytis cinerea and Alternaria alternate will increase with increasing incubation humidity. Aspergillus versicolor, Cladosporium herbarum and Botrytis cinerea will release more fungal fragments (<1m) in the air when incubation period is longer (in week). During the second week of incubation, the total fungal concentration of Aspergillus versicolor and Cladosporium herbaru will reach the highest. The total fungal concentration of Botrytis cinerea will increase with increasing incubation period (in week), it will reach the highest during the fourth week of incubation. Except for Botrytis cinerea, Aspergillus versicolor and Cladosporium herbarum’s total culturable fungi concentration will decrease with increasing incubation period (in week). The result of this study may serve as reference and suggestion for future epidemiology when investigating fungal exposure assessment. According to the result in this study, it’s recommended that in addition to collecting fungal spore concentration to evaluate fungal exposure, we also have to implement size-selective measurement to see the concentration of (1→3)-β-D-glucan. We should take all of these fungal substances into account, because they could cause human respiratory symptoms. The research also indicates that wind speed, incubation temperature, incubation humidity and incubation period have an impact on fungal release in the air. These factors will further affect human exposure to fungi in the environment.