<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Wang, H. C.</style></author><author><style face="normal" font="default" size="100%">Lu, K. D.</style></author><author><style face="normal" font="default" size="100%">Chen, X. R.</style></author><author><style face="normal" font="default" size="100%">Zhu, Q. D.</style></author><author><style face="normal" font="default" size="100%">ZJ Wu</style></author><author><style face="normal" font="default" size="100%">Y.S. Wu</style></author><author><style face="normal" font="default" size="100%">K. Sun</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Fast particulate nitrate formation via N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; uptake aloft in winter in Beijing</style></title><secondary-title><style face="normal" font="default" size="100%">Atmos. Chem. Phys.</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2018</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.atmos-chem-phys.net/18/10483/2018/</style></url></web-urls></urls><pages><style face="normal" font="default" size="100%">10483-10495</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Particulate nitrate (pNO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;) is an important component of secondary aerosols in urban areas. Therefore, it is critical to explore its formation mechanism to assist with the planning of haze abatement strategies. Here we report vertical measurement of NO&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt; and O&lt;sub&gt;3&lt;/sub&gt; by in-situ instruments on a movable carriage on a tower during a winter heavy-haze episode (December 18 to 20, 2016) in urban Beijing, China. Based on the box model simulation at different height, we found that pNO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; formation via N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; heterogeneous uptake was negligible at ground level due to N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; concentration of near zero controlling by high NO emission and NO concentration. In contrast, the contribution from N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; uptake was large at high altitudes (e.g., &amp;gt; 150 m), which was supported by the low total oxidant (NO&lt;sub&gt;2&lt;/sub&gt; + O&lt;sub&gt;3&lt;/sub&gt;) level at high altitudes than that at ground level. Modeling results show the specific case that the nighttime integrated production of pNO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; for the high-altitude air mass above urban Beijing was estimated to be 50 μg m&lt;sup&gt;-3&lt;/sup&gt; and enhanced the surface-layer pNO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; the next morning by 28 μg m&lt;sup&gt;-3&lt;/sup&gt; through vertical mixing. Sensitivity tests suggested that the nocturnal NO&lt;em&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/em&gt; loss by NO&lt;sub&gt;3&lt;/sub&gt;-N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; chemistry was maximized once the N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; uptake coefficient was over 2×10&lt;sup&gt;-3&lt;/sup&gt; on polluted days with &lt;em&gt;S&lt;sub&gt;a&lt;/sub&gt;&lt;/em&gt; was 3000 μm&lt;sup&gt;2&lt;/sup&gt; cm&lt;sup&gt;-3&lt;/sup&gt; in wintertime. The case study provided a chance to highlight that pNO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; formation via N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; heterogeneous hydrolysis may be an important source of the particulate nitrate in the urban airshed during wintertime.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">18</style></issue></record></records></xml>