Global distribution of particle phase state in atmospheric secondary organic aerosols.
Global distribution of particle phase state in atmospheric secondary organic aerosols.
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大气二次有机气溶胶颗粒相态的全局分布
DOI：
10.1038/ncomms15002
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发表时间：
2017-04-21
影响因子：
16.6
通讯作者：
Pöschl U
中科院分区：
文献类型：
--
作者：
Shiraiwa M;Li Y;Tsimpidi AP;Karydis VA;Berkemeier T;Pandis SN;Lelieveld J;Koop T;Pöschl U
二次有机气溶胶（SOA）是我们目前对气候变化和空气污染的理解中的一个很大的不确定性来源。SOA的相态对于量化其对气候和空气质量的影响很重要，但其全球分布特征很差。我们开发了一种基于SOA组分的摩尔质量和分子O：C比来估算玻璃化转变温度的方法，并使用全球化学气候模式EMAC和有机气溶胶模块ORACLE来预测大气SOA的相态。对于行星边界层，全球模拟表明，SOA在热带和极地空气中主要是液体，相对湿度高，在中纬度地区是半固体，在干旱地区是固体。我们发现，在对流层中上部，SOA应该主要处于玻璃固相状态。因此，水、氧化剂和有机分子的缓慢扩散可以在动力学上限制SOA在自由对流层和对流层上部的气-粒相互作用，促进冰成核，并促进嵌入SOA中的活性和有毒有机污染物的长距离传输。二次有机气溶胶（SOA）对气候和气溶胶质量很重要，但相态尚不清楚。在这里，作者表明，SOA在热带和极地空气中是液体，在中纬度地区是半固体，在干旱地区是固体，在对流层中上部是玻璃状的固相状态。
Secondary organic aerosols (SOA) are a large source of uncertainty in our current understanding of climate change and air pollution. The phase state of SOA is important for quantifying their effects on climate and air quality, but its global distribution is poorly characterized. We developed a method to estimate glass transition temperatures based on the molar mass and molecular O:C ratio of SOA components, and we used the global chemistry climate model EMAC with the organic aerosol module ORACLE to predict the phase state of atmospheric SOA. For the planetary boundary layer, global simulations indicate that SOA are mostly liquid in tropical and polar air with high relative humidity, semi-solid in the mid-latitudes and solid over dry lands. We find that in the middle and upper troposphere SOA should be mostly in a glassy solid phase state. Thus, slow diffusion of water, oxidants and organic molecules could kinetically limit gas–particle interactions of SOA in the free and upper troposphere, promote ice nucleation and facilitate long-range transport of reactive and toxic organic pollutants embedded in SOA. Secondary organic aerosols (SOA) are important for climate and aerosol quality, but the phase state is unclear. Here, the authors show that SOA is liquid in tropical and polar air, semi-solid in the mid-latitudes, solid over dry lands and in a glassy solid phase state in the middle and upper troposphere.