Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA.
Indoor Air. 2017 Jul;27(4):791-802. doi: 10.1111/ina.12365. Epub 2017 Jan 13.
Inhalation exposure to elevated particulate matter levels is correlated with deleterious health and well-being outcomes. Despite growing evidence that identifies humans as sources of coarse airborne particles, the extent to which personal exposures are influenced by particle releases near occupants is unknown. In a controlled chamber, we monitored airborne total particle levels with high temporal and particle-size resolution for a range of simulated occupant activities. We also sampled directly from the subject's breathing zone to characterize exposures. A material-balance model showed that a sitting occupant released 8 million particles/h in the diameter range 1-10 μm. Elevated emissions were associated with increased intensity of upper body movements and with walking. Emissions were correlated with exposure, but not linearly. The personal PM exposure increment above the room-average levels was 1.6-13 μg/m during sitting, owing to spatial heterogeneity of particulate matter concentrations, a feature that was absent during walking. The personal cloud was more discernible among larger particles, as would be expected for shedding from skin and clothing. Manipulating papers and clothing fabric was a strong source of airborne particles. An increase in personal exposure was observed owing to particle mass exchange associated with a second room occupant.
吸入高水平的颗粒物会对健康和幸福感产生有害影响。尽管越来越多的证据表明人类是粗颗粒物的来源，但人们对个人暴露在附近居住者释放的颗粒物中的程度知之甚少。在一个受控的房间里，我们监测了空气中总颗粒物水平，具有高时间分辨率和颗粒物尺寸分辨率，模拟了一系列居住者活动。我们还直接从受试者的呼吸区采样，以描述暴露情况。物质平衡模型表明，一个坐着的人在 1-10μm 的直径范围内释放了 800 万个颗粒/小时。排放增加与上身运动强度增加以及行走有关。排放与暴露有关，但不是线性的。与房间平均水平相比，由于颗粒物浓度的空间异质性，坐着时个人 PM 暴露增量为 1.6-13μg/m，而行走时则没有这种情况。个人云在较大的颗粒中更加明显，这是由于皮肤和衣物脱落所致。翻动纸张和衣物是空气中颗粒物的主要来源。由于与第二个房间居住者相关的颗粒质量交换，观察到个人暴露增加。
