虚旋风生物气溶胶采样器的性能测试

发布时间：2018-05-26 09:36

本文选题：生物气溶胶 + 虚旋风采样器　；参考：《华中农业大学》2017年硕士论文

【摘要】：生物气溶胶指由生物来源产生并悬浮于空气中的颗粒物,对生物气溶胶的接触和吸入会导致多种多样的健康问题。生物气溶胶在室内及室外环境均有广泛的分布,不同环境中的生物气溶胶种类不同,对人造成的影响也不同。除此以外,生物气溶胶可以作为云凝结核以及冰核等,对全球气候变化造成影响。对于生物气溶胶的监测是了解其变化及分布规律的重要手段,有助于理解其对空气质量以及气候变化的影响方式。监测的基础是高效的生物气溶胶采样器。目前常用的生物气溶胶采样器包括过滤式、撞击式、液体冲击式以及静电式等,但这些采样器都有一定的适用范围。开展效率稳定且对微生物伤害较小的生物气溶胶采样器的研究在目前仍然具有重要现实意义。因此,本研究构建了生物气溶胶采样器实验室测试系统,利用该测试系统考察了设计参数对虚旋风生物气溶胶采样器物理效率的影响,并进行了再悬浮性能测试、生物效率测试、野外采样测试等,最后与市售采样器Biosampler进行了比较,主要结论如下:(1)改变生物气溶胶发生器中菌液的浓度及发生压强会产生具有不同粒径分布的生物气溶胶,多数大肠杆菌气溶胶处于粒径0.5-1.0μm的范围之间,多数枯草芽孢杆菌营养细胞处于粒径0.7-1.3μm的范围之间,多数黑曲霉孢子处于粒径2.6-3.2μm的范围之间。(2)进口尺寸的减小、曲率半径的增大有利于提高采样器物理效率,但均不如流量的影响显著;在虚旋风生物气溶胶采样器的空腔中加入一定体积的采样液作为捕集介质不会影响采样器的物理效率,且长时间采样后采样液的挥发率仍然比较低;已经捕集到液体中的颗粒物再次悬浮较为困难,可在一定程度上避免颗粒物再悬浮的现象。(3)对于压力敏感性细菌大肠杆菌(ATCC 8739),虚旋风生物气溶胶采样器的生物效率略高于市售采样器Biosampler。(4)实地测试中,虚旋风生物气溶胶采样器与Biosampler在多数情况下的结果均较为相近,没有显著差异,且虚旋风生物气溶胶采样器在多次平行测试之间的差异较小,采样结果较为稳定,然而在某些情况下虚旋风生物气溶胶采样器测得的细菌浓度显著低于Biosampler。(5)在不同的采样时间下,虚旋风生物气溶胶采样器和Biosampler所得的细菌和真菌浓度均值均较为接近,但都会随着采样时间的变化而变化。
[Abstract]:Biological aerosols are particles produced from biological sources and suspended in the air. Contact and inhalation of biological aerosols can lead to a variety of health problems. Biological aerosols are widely distributed in indoor and outdoor environments, and different kinds of biological aerosols in different environments have different effects on human beings. In addition, biological aerosols can act as cloud condensation nuclei and ice nuclei to affect global climate change. The monitoring of biological aerosols is an important means to understand their variation and distribution, which is helpful to understand their influence on air quality and climate change. The monitoring is based on an efficient biological aerosol sampler. The biological aerosol sampler commonly used at present includes filter type, impingement type, liquid impingement type and electrostatic type, but these samplers all have certain application scope. The research of biological aerosol sampler with stable efficiency and less microbial damage is still of great practical significance. Therefore, the laboratory test system of biological aerosol sampler was constructed, and the influence of design parameters on the physical efficiency of virtual cyclone biological aerosol sampler was investigated, and the resuspension performance was tested. The biological efficiency test, field sampling test and so on were compared with the commercial sampler Biosampler. The main conclusions are as follows: 1) changing the concentration and pressure of bacteria solution in the biological aerosol generator will produce biological aerosol with different particle size distribution. Most Escherichia coli aerosols were in the range of 0.5-1.0 渭 m, most of Bacillus subtilis nutrient cells were in the range of 0.7-1.3 渭 m, and most Aspergillus Niger spores were in the range of 2.6-3.2 渭 m. The increase of curvature radius is beneficial to improve the physical efficiency of the sampler, but it is not as significant as the flow rate, and the physical efficiency of the sampler will not be affected by adding a certain volume of sampling solution to the cavity of the virtual cyclone biological aerosol sampler. After a long period of sampling, the volatilization rate of the sample solution is still relatively low, and it is more difficult to suspend the particles that have been captured in the liquid again. To some extent, the phenomenon of particles resuspending can be avoided.) in the field test, the biological efficiency of ATCC8739C and virtual cyclones biological aerosol sampler is slightly higher than that of Biosampler.fl sampler, which is a marketable sampler, for pressure-sensitive bacteria Escherichia coli. The results of virtual cyclone biological aerosol sampler and Biosampler are similar in most cases, and there is no significant difference, and the difference of virtual cyclone biological aerosol sampler in many parallel tests is small, and the sampling results are more stable. However, in some cases, the bacterial concentration measured by the virtual cyclone biological aerosol sampler was significantly lower than that by Biosampler. 5) at different sampling times, the mean bacterial and fungal concentrations obtained from the virtual cyclone biological aerosol sampler and Biosampler were close to each other. But they all change with the sampling time.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X513

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