#大气科学#【论文推荐| 华北典型农业区PM2.5组分分析与来源解析】
作者：曹宇坤, 温天雪, 张小玲, 等.
doi:10.3878/j.issn.1006-9895.2104.20159
摘要 ：华北大气污染区域化正在对农业生态区域产生显著影响，为了了解华北农业地区大气细颗粒物PM2.5的季节分布特征，2017年7月、9月、12月以及2018年4月在中国科学院禹城农业生态综合实验站进行分季节PM2.5样品采集，并测定分析了样品中31种化学成分。结果表明，碳质气溶胶总体的浓度水平为13.11±8.37 μg m−3，有机碳（OC）冬春季节浓度较高，元素碳（EC）浓度在秋冬季节较高。同时OC/EC的比值在秋季明显偏低，表明在秋季二次碳质气溶胶对PM2.5贡献较小。水溶性离子浓度总体在冬季最高。NO3−/SO42−比值在夏季明显偏低为0.69，华北地区夏季固定点源对大气污染的贡献相对较高。PM2.5中金属元素以Na、Mg、Al、Ca、K、Fe等地壳元素为主，具有致癌风险的Co、Cr、Ni、Pb、As等金属元素年均浓度为0.32±0.24 ng m−3、5.40±5.42 ng m−3、10.23±7.46 ng m−3、42.23±27.75 ng m−3、5.66±3.79 ng m−3。受体模型（PMF）计算结果表明，PM2.5的主要来源为二次污染源、生物质燃烧源、燃煤燃油源、柴油车尾气和土壤源，贡献率分别达37.1%、18.2%、14.2%、9.4%和7.9%，表明农业区细颗粒物污染受到华北工业、农业与自然排放的多重影响。
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作者：曹宇坤, 温天雪, 张小玲, 等.
doi:10.3878/j.issn.1006-9895.2104.20159
摘要 ：华北大气污染区域化正在对农业生态区域产生显著影响，为了了解华北农业地区大气细颗粒物PM2.5的季节分布特征，2017年7月、9月、12月以及2018年4月在中国科学院禹城农业生态综合实验站进行分季节PM2.5样品采集，并测定分析了样品中31种化学成分。结果表明，碳质气溶胶总体的浓度水平为13.11±8.37 μg m−3，有机碳（OC）冬春季节浓度较高，元素碳（EC）浓度在秋冬季节较高。同时OC/EC的比值在秋季明显偏低，表明在秋季二次碳质气溶胶对PM2.5贡献较小。水溶性离子浓度总体在冬季最高。NO3−/SO42−比值在夏季明显偏低为0.69，华北地区夏季固定点源对大气污染的贡献相对较高。PM2.5中金属元素以Na、Mg、Al、Ca、K、Fe等地壳元素为主，具有致癌风险的Co、Cr、Ni、Pb、As等金属元素年均浓度为0.32±0.24 ng m−3、5.40±5.42 ng m−3、10.23±7.46 ng m−3、42.23±27.75 ng m−3、5.66±3.79 ng m−3。受体模型（PMF）计算结果表明，PM2.5的主要来源为二次污染源、生物质燃烧源、燃煤燃油源、柴油车尾气和土壤源，贡献率分别达37.1%、18.2%、14.2%、9.4%和7.9%，表明农业区细颗粒物污染受到华北工业、农业与自然排放的多重影响。
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#阿米尔汗离婚##v光计划# 周六上午，阿米尔汗和基兰饶宣布结束15年的婚姻，会继续作为"devoted parents"抚养他们的儿子。基兰饶出生于电影世家，自己也是导演，她的《孟买日记》我很喜欢。一直以为他俩的婚姻是势均力敌的相处。
这封离婚声明像情书一样美，也许人和人的相处就是有很多美好的方式吧：
"In these 15 beautiful years together we have shared a lifetime of experiences, joy and laughter, and our relationship has only grown in trust, respect and love. Now we would like to begin a new chapter in our lives - no longer as husband and wife, but as co-parents and family for each other. "
祝福他们各自都好。
这封离婚声明像情书一样美，也许人和人的相处就是有很多美好的方式吧：
"In these 15 beautiful years together we have shared a lifetime of experiences, joy and laughter, and our relationship has only grown in trust, respect and love. Now we would like to begin a new chapter in our lives - no longer as husband and wife, but as co-parents and family for each other. "
祝福他们各自都好。
Remembering Johnny Mercer !!
John Herndon "Johnny" Mercer
(November 18, 1909 – June 25, 1976) was an American lyricist, songwriter and singer. He was also a co-founder of Capitol Records.
He is best known as a lyricist, but he also composed music. He was also a popular singer who recorded his own songs as well as those written by others. From the mid-1930s through the mid-1950s, many of the songs Mercer wrote and performed were among the most popular hits of the time. He wrote the lyrics to more than fifteen hundred songs, including compositions for movies and Broadway shows. He received nineteen Academy Award nominations, and won four.
Johnny Mercer at Capitol Records, Photo of Special Collections and Archives, Georgia State University Library.
John Herndon "Johnny" Mercer
(November 18, 1909 – June 25, 1976) was an American lyricist, songwriter and singer. He was also a co-founder of Capitol Records.
He is best known as a lyricist, but he also composed music. He was also a popular singer who recorded his own songs as well as those written by others. From the mid-1930s through the mid-1950s, many of the songs Mercer wrote and performed were among the most popular hits of the time. He wrote the lyrics to more than fifteen hundred songs, including compositions for movies and Broadway shows. He received nineteen Academy Award nominations, and won four.
Johnny Mercer at Capitol Records, Photo of Special Collections and Archives, Georgia State University Library.
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