Quantifying particulate matter reduction and their deposition on the leaves of green infrastructure
Quantifying particulate matter reduction and their deposition on the leaves of green infrastructure
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DOI：
10.1016/j.envpol.2020.114884
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发表时间：
2020-10-01
影响因子：
8.9
通讯作者：
Kumar, Prashant
中科院分区：
文献类型：
--
作者：
Abhijith, K., V;Kumar, Prashant
绿色基础设施被认为是一种被动的空气污染暴露控制措施。这项工作考察了路边树篱减少颗粒物（PM）及其在树叶上的沉积。本研究的目的是：(i)量化GI存在时PM浓度与相邻空旷区域的相对差异；（ii）估算沉积在树篱叶片上的PM的总质量和数量密度；（iii）确定树篱两侧成人（1.5米）和儿童（0.6米）呼吸水平处PM沉积的变化；（iv）阐明PM沉积到叶片与环境PM浓度降低之间的关系；(v)量化不同高度和侧面树篱叶片收集颗粒的元素组成。与空旷区相比，在树篱后观察到PM减少了2-9%，并遵循Delta PM1 >Delta PM10 >Delta PM2.5的趋势。粒子计数比称重法更有效地量化沉积。在树篱两侧的所有采样点上，亚微米颗粒（PM1）在叶片上的颗粒沉积中占主导地位。与1.5m高度相比，0.6m高度处临路侧叶片的PM质量沉积量和PM数量浓度分别增加了36%和58%。在树篱的背面却没有这种差别。SEM-EDS分析显示，与背面相比，面向交通的叶片上沉积的交通源颗粒高出12%。在树篱上所有收集点的叶子样本中，自然产生的颗粒占鉴定颗粒的主导地位。这些新证据扩大了我们对道路附近环境中PM对GI的减少及其颗粒沉积变化的理解，这些变化取决于GI的高度和侧面，这可以在微观尺度上为GI评估提供更好的弥散-沉积模型参数化。(C) 2020 Elsevier Ltd.版权所有。
The green infrastructure (GI) is identified as a passive exposure control measure of air pollution. This work examines particulate matter (PM) reduction by a roadside hedge and its deposition on leaves. The objectives of this study are to (i) quantify the relative difference in PM concentration in the presence of GI and at an adjacent clear area; (ii) estimate the total mass and number density of PM deposited on leaves of a hedge; (iii) ascertain variations in PM deposition at adult (1.5m) and child (0.6 m) breathing levels on either side of a hedge; (iv) illustrate the relationship between PM deposition to leaves and ambient PM concentration reductions; and (v) quantify the elemental composition of collected particles of the leaves on different heights and sides of hedge. PM reduction of 2-9% was observed behind hedge compared to a clear area and followed a trend of Delta PM1 >Delta PM10 >Delta PM2.5. Counting of particles was found to be an effective method to quantify deposition than weighting methods. Sub-micron particles (PM1) dominated particle deposition on leaves at all sampling points on both sides of the hedge. PM mass deposition and number concentration to the leaves on traffic-facing side was up to 36% and 58% higher at 0.6m compared with 1.5m height, respectively. Such a difference was absent on the backside of the hedge. The SEM-EDS analysis showed up to 12% higher traffic-originated particles deposited to leaves on the traffic-facing side compared to the backside. The naturally occurring particles dominated in identified particles on leaf samples from all collection points on the hedge. These new evidence expand our understanding of PM reduction of GI in the near-road environment and its variations in particle deposition, depending on height and sides of GI, which could allow a better parameterisation of dispersion-deposition models for GI assessment at micro-scale. (C) 2020 Elsevier Ltd. All rights reserved.