Bacterial loading aggravates the health and environmental hazards of particulate matter (PM), particularly in concentrated animal feeding operations. Understanding the association between PM and airborne bacteria is conducive to accurately assessing occupational exposure, providing fundamental data for exposure mitigation via engineering solutions, and providing information regarding the physical properties influencing the transmission of airborne microorganisms at emission sources. In this work, we conducted a joint study to systematically determine the concentrations and size distributions of PM and airborne bacteria, and establish the quantitative relationship between PM and airborne bacteria in laying hen houses. The association between PM and airborne bacteria was expressed as the load of airborne bacteria on PM in terms of the identical particle size interval based on the size-resolved respiratory tract deposition. The concentrations and size distributions of PM and airborne bacteria in laying hen houses were affected by the in-house space (upper and lower), chicken activity (day and night), and outside temperature. The size distributions of PM and airborne bacteria indicated that the mass concentration of large particles decreased with increasing outside temperature, while the concentration of airborne bacteria loaded on the small particles increased with increasing outside temperature. The results indicated that particles with diameters ranging from 2.1 to 4.7 μm carried the most airborne bacteria. Therefore, particles with diameters ranging from 2.1 to 4.7 μm should be the focus of future experimental research on occupational exposure, air quality improvement, and the airborne transmission of PM and airborne microorganisms originating from concentrated layer feeding operations.

细菌负荷加剧了颗粒物 (PM) 对健康和环境的危害，特别是在集中饲养动物的操作中。了解 PM 与空气传播细菌之间的关联有助于准确评估职业接触，为通过工程解决方案缓解接触提供基础数据，并提供有关影响空气传播微生物在排放源传播的物理特性的信息。在这项工作中，我们进行了一项联合研究，系统地确定了 PM 和空气传播细菌的浓度和大小分布，并建立了蛋鸡舍中 PM 和空气传播细菌之间的定量关系。PM 与空气传播细菌之间的关联表示为基于尺寸分辨的呼吸道沉积的相同粒径区间的空气传播细菌对 PM 的负载。蛋鸡舍内 PM 和空气传播细菌的浓度和大小分布受室内空间（上下）、鸡活动（白天和夜间）和室外温度的影响。PM和空气中细菌的粒径分布表明，大颗粒的质量浓度随着外界温度的升高而降低，而负载在小颗粒上的空气中细菌的浓度随着外界温度的升高而增加。结果表明，直径在 2.1 到 4.7 微米之间的颗粒携带的空气中的细菌最多。因此，粒径范围为 2 的颗粒。