碩士 / 長榮大學 / 職業安全與衛生研究所 / 95 / This study is aimed to investigate the size distribution and concentration of the secondary organic aerosol resulting from the reaction between terpene (600 ppb), commonly found in air freshner, and ozone (100 ppb). The experiments were conducted in a controlled environmental chamber to simulate different combinations of temperature (20℃、25℃、30℃) and relative humidity (RH 30%、50%、70%). The results showed that the particle concentration could reach 1×106 particles/cm3 in the early stage of SOA formation and most particle sizes range between 50 nm ~ 100 nm. As observation continues, particle number concentration decreases while the particle size increases due to coagulation. The number concentration remained at 2×105 particles ／cm3, approximately twenty folds of background concentration. Previous studies pointed out that the sizes of SOA exceed 100 nm, while the current study found that SOAs in the initial stage range between 50nm to 100nm and some even smaller than 50nm.
The results also indicated the formation of SOA is affected by temperature and relative humidity. When temperature is constant, the particle number concentration decreases with the increasing relative humidity, while the number concentration decreases with the increasing temperature under the condition of constant relative humidity. Same trend was found for ultrafine particles （dp＜100nm）.
The results of air sampling from office with photocopier indicated that office environments with poor ventilation (air exchange per hour less than 1) accumulate greater concentration of fine particles. More particles were emitted during one episode of large volume of photocopying than many periodic photocopying. Moreover, the indoor particle concentration is affected easily by the outdoor environment. As the particle size observed in the current study are lower than 100 nm, the observed number concentration is approximately 10 times of those from the same reactants found in the literature. This study concluded that the health risk of occupants exposed to the indoor SOAs should not be overlooked.。
| Identifer | oai:union.ndltd.org:TW/093CJU00590010 |
| Date | January 2007 |
| Creators | Jui-Chuan Lee, 李瑞權 |
| Contributors | Der-Jen Hsu, 許德仁 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 61 |
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