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首页> 外文期刊>Atmospheric chemistry and physics >Simultaneous measurements of new particle formation at 1?s time resolution at a street site and a rooftop site
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Simultaneous measurements of new particle formation at 1?s time resolution at a street site and a rooftop site

机译：在街道站点和屋顶站点以1？s的时间分辨率同时测量新颗粒的形成

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This study is the first to use two identical Fast Mobility Particle Sizers for simultaneous measurement of particle number size distributions (PNSDs) at a street site and a rooftop site within 500?m distance in wintertime and springtime to investigate new particle formation (NPF) in Beijing. The collected datasets at 1?s time resolution allow deduction of the freshly emitted traffic particle signal from the measurements at the street site and thereby enable the evaluation of the effects on NPF in an urban atmosphere through a site-by-site comparison. The number concentrations of 8 to 20?nm newly formed particles and the apparent formation rate (FR) in the springtime were smaller at the street site than at the rooftop site. In contrast, NPF was enhanced in the wintertime at the street site with FR increased by a factor of 3 to 5, characterized by a shorter NPF time and higher new particle yields than at the rooftop site. Our results imply that the street canyon likely exerts distinct effects on NPF under warm or cold ambient temperature conditions because of on-road vehicle emissions, i.e., stronger condensation sinks that may be responsible for the reduced NPF in the springtime but efficient nucleation and partitioning of gaseous species that contribute to the enhanced NPF in the wintertime. The occurrence or absence of apparent growth for new particles with mobility diameters larger than 10?nm was also analyzed. The oxidization of biogenic organics in the presence of strong photochemical reactions is suggested to play an important role in growing new particles with diameters larger than 10?nm, but sulfuric acid is unlikely to be the main species for the apparent growth. However, the number of datasets used in this study is relatively small, and larger datasets are essential to draw a general conclusion.
机译：这项研究是首次使用两个相同的快速迁移粒度仪同时测量冬季和春季500微米距离内的街道站点和屋顶站点的颗粒大小分布（PNSD），以调查新的颗粒形成（NPF）。北京。以1？s的时间分辨率收集的数据集可以从街道站点的测量值中减去新发出的交通粒子信号，从而可以通过逐站点比较来评估对城市大气中NPF的影响。在春季，新形成的颗粒数量浓度为8至20？nm，表观形成率（FR）小于屋顶站点。相比之下，冬季冬季街道现场的NPF有所提高，FR增加了3到5倍，其特点是与屋顶站点相比，NPF时间更短，新颗粒的产量更高。我们的结果表明，由于道路上的车辆排放，在温暖或寒冷的环境温度条件下，街道峡谷可能会对NPF产生明显的影响，即较强的冷凝水槽可能导致春季NPF降低，但有效的成核和分隔作用冬季增加NPF的气态物种。还分析了迁移直径大于10？nm的新粒子是否出现明显的生长。在强烈的光化学反应存在下，生物有机物的氧化被认为在生长直径大于10？nm的新颗粒中起重要作用，但是硫酸不太可能成为表观生长的主要物质。但是，本研究中使用的数据集数量相对较少，并且较大的数据集对于得出一般结论至关重要。

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