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首页> 外文会议>Annual conference of the International Society of Exposure Science >Counterfactual behaviour of ultrafine particles in infiltration and lung deposition processes
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Counterfactual behaviour of ultrafine particles in infiltration and lung deposition processes

机译：超细颗粒在浸润和肺部沉积过程中的反事实行为

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A commonly used justification of concern for ultrafine aka nanoparticles is their high deposition probability in the alveolar region of human respiratory tract. This is often phrased as 'capability of penetrating deep in the lung'. While the higher probability of an ultrafine particle being deposited in the alveolar than other regions of the lung is well established, it is also clear - yet not as widely recognized - that the deposited mass in the alveolar region is almost certainly dominated by larger particles, as the particle masses increase much more rapidly as function of particle size than the deposition probability decreases. However, it is easily forgotten that infiltration process also significantly modifies the ambient particle size distribution due to the particle size driven differences in the penetration and deposition rates indoors. The objective of the current work is to quantitatively compare these processes using a previously developed and evaluated particle size dependent infiltration model and the ICRP (1994) model for respiratory tract uptake. The results show that time spent indoors substantially modifies the uptake of ultrafine particles. Human doses to ambient ultrafine particles are to a very large extent obtained outdoors and in traffic environments, while the PM2.5 uptakes are dominated by indoor environments. As a consequence time-activity variables are likely to be sufficient for qualitatively estimating the impact of ambient ultrafine particles on health in epidemiological settings. Indoors exposure and uptake of ultrafine particles takes place by accumulation mode carriers; i.e. the ultrafine particles are partly attached to larger particles, which in the accumulation mode size range effectively transports them indoors. Indoors mass uptake is dominated by accumulation mode as also coarse (super micron) particles are effectively removed from the breathing air by the building envelope and subsequent indoor deposition.
机译：关于超细又名纳米颗粒的普遍关注的理由是它们在人呼吸道的肺泡区域中的高沉积可能性。通常将其表述为“穿透肺深处的能力”。尽管已经确定了超细颗粒沉积在肺泡中的可能性要高于肺的其他区域，但也很明显但尚未得到广泛认可，几乎可以肯定的是，肺泡区域中的沉积物质几乎是由较大的颗粒所控制的，随颗粒质量的增加，随着颗粒质量的增加，其沉积概率的下降要快得多。但是，很容易忘记，由于粒径驱动室内渗透和沉积速率的差异，因此渗透过程也会显着改变环境粒径分布。当前工作的目的是使用先前开发和评估的粒径依赖性渗透模型和ICRP（1994）模型对呼吸道摄取进行定量比较，以比较这些过程。结果表明，在室内度过的时间大大改变了超细颗粒的吸收。在室外和交通环境中，人体对环境超细颗粒的剂量在很大程度上获得了，而PM2.5的吸收则主要由室内环境决定。结果，时间活动变量可能足以定性评估流行病学环境中环境超细颗粒对健康的影响。在室内，超细颗粒的暴露和吸收是通过积累模式的载体发生的。即，超细颗粒部分地附着在较大颗粒上，较大颗粒在积累模式尺寸范围内有效地将其输送到室内。室内的质量吸收以积累模式为主导，因为建筑物的围护结构和随后的室内沉积也有效地从呼吸空气中去除了较粗（超微米）的颗粒。

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