Contributions of Coagulation, Deposition, and Ventilation to the Removal of Airborne Nanoparticles in Indoor Environments
Contributions of Coagulation, Deposition, and Ventilation to the Removal of Airborne Nanoparticles in Indoor Environments
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DOI：
10.1021/acs.est.0c08739
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发表时间：
2021-07-02
影响因子：
11.4
通讯作者：
Rim, Donghyun
中科院分区：
文献类型：
--
作者：
Jeong, Su-Gwang;Wallace, Lance;Rim, Donghyun
由于偶发的室内源活动，空气中的纳米颗粒经常在占用的空间中释放。纳米颗粒一旦产生，就会经历凝固和沉积等气溶胶转化过程。这些气溶胶过程导致颗粒浓度和大小分布随时间的变化，从而影响人类对纳米颗粒的暴露。本研究建立了一个室内颗粒动力学模型框架，该模型可以预测偶发性室内排放事件后随时间和尺寸变化的颗粒浓度。该模型用从文献中先前的测量研究中获得的六个实验数据集进行了评估。室内颗粒动力学模型量化了三种颗粒损失机制（即混凝、沉积和通风）对总数浓度降低的相对贡献。结果表明，室内排放事件发生后，颗粒凝聚和室内表面沉积是导致颗粒大小和浓度变化的两个主要过程。一阶等效混凝损失率随室内排放源的变化显著，燃烧蜡烛、烤鱼和烧香的混凝损失率分别占总颗粒损失率的59%、42%和10%。结果表明，混凝损失率随颗粒浓度和来源类型的变化而显著变化，而沉积损失率则更多地取决于颗粒大小。与凝结和沉积相比，通风对室内大多数纳米颗粒排放事件的影响微乎其微；然而，当颗粒浓度低于5 × 10(4) cm（-3）时，尤其是空气动力学直径大于100 nm的颗粒，通气损失变得明显。
Airborne nanoparticles are frequently released in occupied spaces due to episodic indoor source activities. Once generated, nanoparticles undergo aerosol transformation processes such as coagulation and deposition. These aerosol processes lead to changes in particle concentration and size distribution over time and accordingly affect human exposure to nanoparticles. The present study establishes a framework for an indoor particle dynamic model that can predict time- and size-dependent particle concentrations after episodic indoor emission events. The model was evaluated with six experimental data sets obtained from previous measurement studies in the literature. The indoor particle dynamic model quantified the relative contributions of three particle loss mechanisms (i.e., coagulation, deposition, and ventilation) to the total reduction in number concentration. The results show that particle coagulation and indoor surface deposition are two dominant processes responsible for temporal changes in particle size and concentration following indoor emission events. The first-order equivalent coagulation loss rate notably varies with indoor emission source and accounts for up to 59% of the total particle loss for burning a candle, 42% for broiling a fish, and 10% for burning incense. The results reveal that while the coagulation loss rate changes markedly with the particle concentration and source type, the deposition loss rate is more dependent on particle size. Compared to coagulation and deposition, the effect of ventilation is marginal for most of the nanoparticle emission events indoors; however, ventilation loss becomes pronounced with the decrease of particle concentration below 5 x 10(4) cm(-3) especially for particles larger than 100 nm in aerodynamic diameter.