为了研究微米量级微生物凝聚粒子群所构成的复杂介质环境对入射激光透射率的影响，采用团簇-团簇凝聚模型模拟了微生物凝聚粒子的空间结构；利用离散偶极子近似方法计算其单次散射参量；通过蒙特卡罗仿真研究了10.6 μm 激光在微生物凝聚粒子群中的透射率。结果表明：当每个微生物凝聚粒子包含20~50 个半径为1.5 μm的原始微粒，凝聚粒子数密度大于800 /cm3 ，测量区厚度为4 m 时，将孔隙率的值控制在0.9 以下，可使10.6 μm 激光在微生物凝聚粒子群中的透射率小于10%。

Complex media environment which is composed of micrometer-level microorganism aggregated particle swarm has great impact on laser transmittance. To study what the impact is, based on fractal theory, a cluster-cluster aggregation (CCA) model is used to simulate the fractal structure of microorganism aggregated particles, and the single scattering extinction parameters for aggregated particles are calculated using the discrete dipole approximation (DDA) method. Then the transmittance of 10.6 μm laser in microorganism aggregated particle swarm is studied with the Monte Carlo method. The results show that when each aggregated particle contains 20~50 original particles, the radius of original particle is 1.5 μm , the density of aggregated particles is higher than 800 /cm3 , and the porosity is less than 0.9, the transmittance of 10.6 μm laser in the microorganism aggregated particle swarm which has a 4 m-thick measurement area can be less than 10%.