Understanding the deposition of bioaerosols in the respiratory system may help determine the risk of disease; however, measuring deposition fraction in-situ is difficult. Computational models provide estimates of particle deposition fraction for given breathing and particle parameters; however, these models traditionally have not focused on bioaerosols. We calculated deposition fractions in an average-sized adult with a new bioaerosol-specific lung deposition model, BAIL, and with two multiple-path models for three different breathing scenarios: “default” (subject sitting upright and breathing nasally), “light exercise”, and “mouth breathing”. Within each scenario, breathing parameters and bioaerosol characteristics were kept the same across all three models. BAIL generally calculated a higher deposition fraction in the extrathoracic (ET) region and a lower deposition fraction in the alveolar region than the multiple-path models. Deposition fractions in the tracheobronchial region were similar among the three models; total deposition fraction patterns tended to be driven by the ET deposition fraction, with BAIL resulting in higher deposition in some scenarios. The difference between deposition fractions calculated by BAIL and other models depended on particle size, with BAIL generally indicating lower total deposition for bacteria-sized bioaerosols. We conclude that BAIL predicts somewhat lower deposition and, potentially, reduced risk of illness from smaller bioaerosols that cause illness due to deposition in the alveolar region. On the other hand, it suggests higher deposition in the ET region, especially for light exercise and mouth-breathing scenarios. Additional comparisons between the models for other breathing scenarios, people’s age, and different bioaerosol particles will help improve our understanding of bioaerosol deposition.

中文翻译：

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两种评估人体呼吸道中真菌和细菌沉积的模型的比较

了解呼吸系统中生物气溶胶的沉积可能有助于确定疾病的风险；但是，很难现场测量沉积分数。计算模型提供了给定呼吸和颗粒参数下颗粒沉积分数的估计值；然而，这些模型传统上并不专注于生物气溶胶。我们使用新的特定于生物气溶胶的肺部沉积模型BAIL，以及针对三种不同呼吸场景的两种多径模型，计算了一个普通大小成年人的沉积分数：“默认”（受试者坐直并通过鼻呼吸），“轻度锻炼” ”和“口呼吸”。在每种情况下，所有三个模型的呼吸参数和生物气溶胶特征均保持相同。与多径模型相比，BAIL通常计算出胸外（ET）区域的沉积分数更高，而肺泡区域的沉积分数更低。在这三个模型中，气管支气管区域的沉积分数相似。总沉积分数模式倾向于由ET沉积分数驱动，而BAIL在某些情况下会导致较高的沉积。通过BAIL和其他模型计算的沉积分数之间的差异取决于颗粒大小，BAIL通常表明细菌大小的生物气溶胶的总沉积较低。我们得出的结论是，BAIL预测较小的生物气溶胶会降低沉积物，并有可能降低疾病风险，因为较小的生物气溶胶会由于肺泡区域的沉积而引起疾病。另一方面，这表明ET区域的沉积较高，特别是对于轻度运动和令人屏息的场景。在其他呼吸场景，人们的年龄以及不同的生物气溶胶颗粒之间的模型之间的其他比较，将有助于增进我们对生物气溶胶沉积的理解。