<?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%">Yuan Chen</style></author><author><style face="normal" font="default" size="100%">Xie, Shao-dong</style></author><author><style face="normal" font="default" size="100%">Bin Luo</style></author><author><style face="normal" font="default" size="100%">Zhai, Chong-zhi</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Particulate pollution in urban Chongqing of southwest China: Historical trends of variation, chemical characteristics and source apportionment</style></title><secondary-title><style face="normal" font="default" size="100%">Science of The Total Environment</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2017</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.sciencedirect.com/science/article/pii/S004896971730061X?via%3Dihub</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Elsevier</style></publisher><volume><style face="normal" font="default" size="100%">584</style></volume><pages><style face="normal" font="default" size="100%">523–534</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span&gt;Chongqing, the largest&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/megacity&quot; title=&quot;Learn more about megacity&quot;&gt;megacity&lt;/a&gt;&lt;span&gt;&amp;nbsp;in southwest China, faces serious&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/aerosol&quot; title=&quot;Learn more about aerosol&quot;&gt;aerosol&lt;/a&gt;&amp;nbsp;pollution but lacks information on particle characteristics and its sources. Official data released by Chongqing Environmental Protection Bureau demonstrated that urban PM&lt;/span&gt;&lt;/span&gt;&lt;span&gt;10&lt;/span&gt;&lt;span&gt;&amp;nbsp;concentrations decreased remarkably from 150&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;m&lt;/span&gt;&lt;span&gt;−&amp;nbsp;3&lt;/span&gt;&lt;span&gt;&amp;nbsp;in 2000 to 90&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;m&lt;/span&gt;&lt;span&gt;−&amp;nbsp;3&lt;/span&gt;&lt;span&gt;&amp;nbsp;in 2012. However, only several peer-reviewed studies paid attention to local fine particle (PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;) pollution. In the study, PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;&amp;nbsp;samples were obtained and subjected to chemical analysis in an urban site of the city during 2012 to 2013. The annual mean PM&lt;/span&gt;&lt;span&gt;10&lt;/span&gt;&lt;span&gt;&amp;nbsp;and PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;&amp;nbsp;concentrations in urban Chongqing were 103.9&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;±&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;52.5 and 75.4&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;±&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;42.2&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;μg&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;m&lt;/span&gt;&lt;span&gt;−&amp;nbsp;3&lt;/span&gt;&lt;span&gt;, respectively. PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;&amp;nbsp;showed a distinct seasonality of high concentration in winter and similar levels in other seasons. The average OC/EC (organic carbon/element carbon) ratio was 3.7 with more high-OC/EC ratio sources contribution in autumn and winter. The varying sources and&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/formation-mechanism&quot; title=&quot;Learn more about formation mechanism&quot;&gt;formation mechanisms&lt;/a&gt;&amp;nbsp;resulted in SO&lt;/span&gt;&lt;span&gt;4&lt;/span&gt;&lt;span&gt;2&amp;nbsp;−&lt;/span&gt;&lt;span&gt;&amp;nbsp;and NH&lt;/span&gt;&lt;span&gt;4&lt;/span&gt;&lt;span&gt;+&lt;/span&gt;&lt;span&gt;&amp;nbsp;peaks in both summer and winter, whereas high nitrate concentration was only observed in winter. In the average mass closure, PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;&amp;nbsp;was composed of 23.0% SO&lt;/span&gt;&lt;span&gt;4&lt;/span&gt;&lt;span&gt;2&amp;nbsp;−&lt;/span&gt;&lt;span&gt;, 11.7% NO&lt;/span&gt;&lt;span&gt;3&lt;/span&gt;&lt;span&gt;−&lt;/span&gt;&lt;span&gt;, 10.9% NH&lt;/span&gt;&lt;span&gt;4&lt;/span&gt;&lt;span&gt;+&lt;/span&gt;&lt;span&gt;, 30.8% OM (organic matter), 5.2% EC, 8.2% mineral dust, 0.6% TEO (trace elements), 1.0% Cl&lt;/span&gt;&lt;span&gt;−&lt;/span&gt;&lt;span&gt;&amp;nbsp;and 1.1% K&lt;/span&gt;&lt;span&gt;+&lt;/span&gt;&lt;span&gt;, while exhibiting large seasonal variability. Using positive matrix&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/factorization&quot; title=&quot;Learn more about factorization&quot;&gt;factorization&lt;/a&gt;&amp;nbsp;(PMF), six sources were apportioned in PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;&lt;span&gt;&lt;span&gt;: secondary inorganic aerosols,&amp;nbsp;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/coal-combustion&quot; title=&quot;Learn more about Coal Combustion&quot;&gt;coal combustion&lt;/a&gt;, other&amp;nbsp;&lt;/span&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/industrial-pollution&quot; title=&quot;Learn more about industrial pollution&quot;&gt;industrial pollution&lt;/a&gt;, soil dust, vehicular emission, and&amp;nbsp;&lt;/span&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/metallurgical-industry&quot; title=&quot;Learn more about metallurgical industry&quot;&gt;metallurgical industry&lt;/a&gt;. The annual mean contribution of above sources to PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;&amp;nbsp;was 37.5, 22.0, 17.5, 11.0, 9.8 and 2.2%, respectively. Coal combustion was identified by As tracer and dominated the primary sources of PM&lt;/span&gt;&lt;span&gt;2.5&lt;/span&gt;&lt;span&gt;, while the two different industrial sources were characterized by Cr and Mo, Co, Ni, and Se, respectively. The study is of great importance in characterizing the historical trends, current chemical characteristics and sources of fine particles in urban Chongqing.&lt;/span&gt;&lt;/p&gt;</style></abstract></record></records></xml>