Atmospheric peroxyacetyl nitrate (PAN): a global budget and source attribution
Atmospheric peroxyacetyl nitrate (PAN): a global budget and source attribution
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DOI：
10.5194/acp-14-2679-2014
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发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Deolal, S. Pandey
中科院分区：
文献类型：
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作者：
Fischer, E. V.;Jacob, D. J.;Deolal, S. Pandey
在非甲烷挥发性有机化合物（NMVOCs）的大气氧化中形成的过氧乙酰硝酸酯（PAN）是氮氧化物自由基（NOx = NO+ NO2）的主要对流层储存库。PAN使氮氧化物的运输和释放到遥远的对流层的臭氧和OH，对流层的主要氧化剂的全球分布的重大影响。PAN的模拟对全球模型来说是一个挑战，因为PAN依赖于垂直传输以及复杂和不确定的NMVOC来源和化学。在这里，我们使用了一个改进的表示NMVOCs在全球3-D化学传输模型（GEOS-Chem），并表明它可以模拟PAN观测全球飞机运动。PAN形成的直接羰基前体包括乙醛（占全球来源的44%）、丙酮醛（30%）、丙酮（7%）和一系列其他异戊二烯和萜烯氧化产物（19%）。多种NMVOC排放是全球PAN形成的原因，包括异戊二烯（37%）和烷烃（14%）。在生长季节以外的热带外北方半球，人为来源占主导地位。除了春季北方高纬度地区外，明火似乎起不了什么作用，尽管结果对羽流化学和羽流上升非常敏感。闪电氮氧化物是在南大西洋上空的自由对流层中观察到的PAN最大值的主要贡献者。
Peroxyacetyl nitrate (PAN) formed in the atmospheric oxidation of non-methane volatile organic compounds (NMVOCs) is the principal tropospheric reservoir for nitrogen oxide radicals (NOx = NO+ NO2). PAN enables the transport and release of NOx to the remote troposphere with major implications for the global distributions of ozone and OH, the main tropospheric oxidants. Simulation of PAN is a challenge for global models because of the dependence of PAN on vertical transport as well as complex and uncertain NMVOC sources and chemistry. Here we use an improved representation of NMVOCs in a global 3-D chemical transport model (GEOS-Chem) and show that it can simulate PAN observations from aircraft campaigns worldwide. The immediate carbonyl precursors for PAN formation include acetaldehyde (44% of the global source), methylglyoxal (30%), acetone (7%), and a suite of other isoprene and terpene oxidation products (19%). A diversity of NMVOC emissions is responsible for PAN formation globally including isoprene (37%) and alkanes (14%). Anthropogenic sources are dominant in the extratropical Northern Hemisphere outside the growing season. Open fires appear to play little role except at high northern latitudes in spring, although results are very sensitive to plume chemistry and plume rise. Lightning NOx is the dominant contributor to the observed PAN maximum in the free troposphere over the South Atlantic.