Altria Client Services, Research Development and Engineering, Richmond, Virginia 23219, USA.
Inhal Toxicol. 2010 Feb;22(3):199-209. doi: 10.3109/08958370903161224.
It is known that puffing conditions such as puff volume, duration, and frequency vary substantially among individual smokers. This study investigates how these parameters affect the particle size distribution and concentration of fresh mainstream cigarette smoke (MCS) and how these changes affect the predicted deposition of MCS particles in a model human respiratory tract. Measurements of the particle size distribution made with an electrical low pressure impactor for a variety of puffing conditions are presented. The average flow rate of the puff is found to be the major factor effecting the measured particle size distribution of the MCS. The results of these measurements were then used as input to a deterministic dosimetry model (MPPD) to estimate the changes in the respiratory tract deposition fraction of smoke particles. The MPPD dosimetry model was modified by incorporating mechanisms involved in respiratory tract deposition of MCS: hygroscopic growth, coagulation, evaporation of semivolatiles, and mixing of the smoke with inhaled dilution air. The addition of these mechanisms to MPPD resulted in reasonable agreement between predicted airway deposition and human smoke retention measurements. The modified MPPD model predicts a modest 10% drop in the total deposition efficiency in a model human respiratory tract as the puff flow rate is increased from 1050 to 3100 ml/min, for a 2-s puff.
众所周知，吸烟时的吸烟条件，如吸烟量、持续时间和频率，在不同的吸烟者之间有很大的差异。本研究旨在探讨这些参数如何影响新鲜主流香烟烟雾（MCS）的颗粒尺寸分布和浓度，以及这些变化如何影响模型人体呼吸道中 MCS 颗粒的预测沉积。本研究展示了采用电低压撞击器对各种吸烟条件下的颗粒尺寸分布进行的测量结果。结果发现，吸烟的平均流速是影响 MCS 测量颗粒尺寸分布的主要因素。然后，将这些测量结果用作输入，以一种确定性剂量模型（MPPD）来估算呼吸道中烟雾颗粒沉积分数的变化。通过将涉及 MCS 呼吸道沉积的机制（吸湿增长、凝聚、半挥发性物质的蒸发以及烟雾与吸入稀释空气的混合）纳入到 MPPD 剂量模型中，对 MPPD 剂量模型进行了修改。将这些机制添加到 MPPD 中后，预测的气道沉积与人体烟雾保留测量值之间的一致性良好。改良后的 MPPD 模型预测，在 2 秒的吸烟过程中，吸烟量从 1050 毫升/分钟增加到 3100 毫升/分钟时，模型人体呼吸道中的总沉积效率会适度下降 10%。
