Lee Shu-An, Adhikari Atin, Grinshpun Sergey A, McKay Roy, Shukla Rakesh, Reponen Tiina
Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio 45267-0056, USA.
J Occup Environ Hyg. 2006 Mar;3(3):118-30. doi: 10.1080/15459620500524607.
Airborne dust and microorganisms are associated with respiratory diseases and increased mortality and morbidity. Farmers are at high risk of exposure to both of these hazards. Very limited information, however, is available on the combined exposures to both hazards on different types of farms. Moreover, most of the previous studies have measured the mass concentration of particles ignoring the particle size. In this study, farmers' exposure to airborne dust and microorganisms was studied using our newly developed personal sampling system. Particle number concentration and size distribution were measured with an optical particle counter. Simultaneously, particles were collected on a filter and analyzed for microorganisms. The field measurements were conducted in animal confinements (swine, poultry, and dairy) and during grain harvesting (corn and soybean). The results show the following average concentrations on the workers' breathing zone: 1.7 x 10(6) to 2.9 x 10(7) particles/m(3) for total dust, 0.9 x 10(3) to 3.9 x 10(4) spores/m(3) for total fungal spores, 0.3 x 10(3) to 3.6 x 10(4)CFU/m(3) for culturable fungal spores, 0.3 x 10(4) to 3.3 x 10(8) CFU/m(3) for culturable bacteria, and limit of detection (LOD) to 2.8 x 10(3) CFU/m(3) for culturable actinomycetes in animal confinements. The respective concentrations were 4.4 x 10(6) to 5.8 x 10(7) particles/m(3), 3.4 x 10(4) to 6.1 x 10(6) spores/m(3), 8.2 x 10(4) to 7.4 x 10(6) CFU/m(3), 0.4 x 10(5) to 1.4 x 10(6) CFU/m(3), and LOD to 2.6 x 10(4) CFU/m(3) during grain harvesting. The highest contribution of large particles (3-10 microm) in total particles was found during grain harvesting, whereas the size distribution was dominated by smaller particles (< 3 microm) in animal confinements. High fraction (up to 37%) of particles between 2-10 microm was found to be fungal spores. The results indicate that an increase in the concentration of large dust particles (2-10 microm) during grain harvesting was partially attributed to the increase in the concentration of the fungal spores. Overall, the combined exposure to airborne dust and microorganisms was found to be more severe during harvesting than in animal confinements.
空气中的灰尘和微生物与呼吸系统疾病以及死亡率和发病率的增加有关。农民面临着接触这两种危害的高风险。然而，关于不同类型农场同时接触这两种危害的信息非常有限。此外，以前的大多数研究都测量了颗粒物的质量浓度，而忽略了粒径。在本研究中，使用我们新开发的个人采样系统研究了农民接触空气中灰尘和微生物的情况。用光学粒子计数器测量粒子数浓度和粒径分布。同时，将粒子收集在滤膜上并分析其中的微生物。现场测量在动物饲养场所（猪、家禽和奶牛场）以及谷物收获期间（玉米和大豆）进行。结果显示工人呼吸区内的以下平均浓度：总灰尘为1.7×10⁶至2.9×10⁷个粒子/立方米，总真菌孢子为0.9×10³至3.9×10⁴个孢子/立方米，可培养真菌孢子为0.3×10³至3.6×10⁴CFU/立方米，可培养细菌为0.3×10⁴至3.3×10⁸CFU/立方米，动物饲养场所中可培养放线菌的检测限为2.8×10³CFU/立方米。谷物收获期间的相应浓度分别为4.4×10⁶至5.8×10⁷个粒子/立方米、3.4×10⁴至6.1×10⁶个孢子/立方米、8.2×10⁴至7.4×10⁶CFU/立方米,0.4×10⁵至1.4×10⁶CFU/立方米，检测限为2.6×10⁴CFU/立方米。在谷物收获期间发现大颗粒（3至10微米）在总颗粒中的贡献最大，而在动物饲养场所中粒径分布以较小颗粒（<3微米）为主。发现2至10微米之间的颗粒中有很大一部分（高达37%）是真菌孢子。结果表明，谷物收获期间大灰尘颗粒（2至10微米）浓度的增加部分归因于真菌孢子浓度的增加。总体而言，发现收获期间空气中灰尘和微生物的综合接触比动物饲养场所更为严重。
