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Are glyoxal and methylglyoxal critical to the formation of a missing fraction of SOA (Secondary Organic Aerosol)?: (Pho-SOA).

乙二醛和甲基乙二醛对于 SOA（二次有机气溶胶）缺失部分的形成至关重要吗？：（Pho-SOA）。

基本信息

批准号：
NE/H021140/1
负责人：
Paul Monks
金额：
$ 25.4万
依托单位：
University of Leicester
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FH021140%2F1
关键词：
glyoxal methylglyoxal critical formation missing

项目摘要

Atmospheric aerosols are ubiquitous in the Earth's atmosphere. They are made up of complex colloidal mixtures of liquid and solid particulate matter and understanding their chemical and physical properties is crucial in elucidating their environmental and health impacts. However, despite much scientific effort over the last decade, the true impact of aerosols on the Earth's atmosphere is yet to be elucidated owing to large uncertainties and lack of fundamental knowledge on their sources, composition (hence physical properties) and formation mechanisms. Recent experimental findings indicate organic aerosols (OA) are predominantly secondary in nature and can account for a significant fraction (10-70%) of total ambient atmospheric aerosol5. However, current models significantly underestimate SOA (Secondary Organic Aerosol) production and their rate of formation. Accretion or oligomerization reactions of light weight volatiles such as glyoxal (GLY, CH(O)CHO) and methylglyoxal (MGLY, CH3C(O)CHO), which have been shown to be a potentially important source of global SOA, have been proposed to justify such disagreement. The magnitude, type (reversible or irreversible) and mechanism of particle formation owing to alfa-dicarbonyls are still substantial questions. The aim of this project is to quantitatively demonstrate the hypothesis that heterogeneous uptake of GLY and MGLY in aerosols can explain a significant fraction of the missing SOA in models. To address this aim, the project will carry out an extensive series of outdoor chamber experiments that will address the main limitations of previous studies. The experimental work will be supported by detailed chamber modelling using the Master Chemical Mechanism (MCM). GLY or MGLY will either be introduced directly into the chamber or generated in-situ by the reaction of OH + alkynes. The chamber experiments will be carried out in the presence (and absence) of natural solar radiation in the highly instrumented outdoor European Photoreactor (EUPHORE) in order to investigate whether reactive uptake of these dicarbonyl compounds and SOA growth is photochemically activated (photosensitized) and relative humidity dependent. The gas and aerosol phase evolution of the precursor and oxidation products, together with HOx radicals (OH + HO2) will be monitored using novel chemical ionisation reaction (time-of-flight, quadrupole and Hadamard Transform) mass spectrometry (CIR-MS), Aerosol Time of Flight Mass Spectrometry (ATOFMS), Fourier Transform Ion Cyclotron resonance Mass Spectrometry (FTICR-MS), liquid chromatography-ion trap mass spectrometry (LC-MSn) and laser induced fluorescence (LIF). Moreover, model sensitivity simulations using the MCM coupled to a representation of absorptive gas-to-aerosol partitioning incorporating parameterisations from the findings of this study will be carried out in order to investigate the atmospheric implications of SOA formation via heterogeneous uptake of dicarbonyl compounds for urban environment where aromatics compounds (significant sources of dicarbonyls) have been proposed as key urban SOA sources. These experiments are critical to quantifying a key potential formation pathway for SOA. .

大气气溶胶在地球大气中无处不在。它们由液体和固体颗粒物质的复杂胶体混合物组成，了解它们的化学和物理特性对于阐明它们对环境和健康的影响至关重要。然而，尽管在过去十年中做出了许多科学努力，但由于存在很大的不确定性，而且缺乏关于气溶胶来源、成分（因此也就是物理特性）和形成机制的基本知识，气溶胶对地球大气层的真正影响尚未得到阐明。最近的实验结果表明，有机气溶胶（OA）在性质上主要是二次性的，可以占环境大气气溶胶总量的很大一部分（10-70%）。然而，目前的模型显着低估了SOA（二次有机气溶胶）的生产和他们的形成速度。轻质挥发物如乙二醛（GLY，CH（O）CHO）和甲基乙二醛（MGLY，CH 3C（O）CHO）的聚集或低聚反应已被证明是全球SOA的潜在重要来源，已被提出来证明这种分歧。由于α-二羰基化合物形成粒子的大小、类型（可逆或不可逆）和机制仍然是实质性的问题。本项目的目的是定量地证明气溶胶中GLY和MGLY的非均匀吸收可以解释模型中缺失SOA的重要部分的假设。为了实现这一目标，该项目将进行一系列广泛的室外室实验，以解决以前研究的主要局限性。实验工作将得到使用主化学机制（MCM）的详细腔室建模的支持。GLY或MGLY将直接引入腔室中或通过OH +炔的反应原位产生。室实验将进行在存在（和不存在）的天然太阳辐射的高度仪表化的室外欧洲光反应器（EUPHORE），以调查是否反应性吸收这些二羰基化合物和SOA的增长是光化学激活（光敏化）和相对湿度的依赖。前体和氧化产物以及HOx自由基的气相和气溶胶相演化（OH + HO 2）将使用新的化学电离反应进行监测（飞行时间、四极杆和阿达玛变换）质谱（CIR-MS）、气溶胶飞行时间质谱（ATOFMS）、傅立叶变换离子回旋共振质谱质谱（FTICR-MS）、液相色谱-离子阱质谱（LC-MSn）和激光诱导荧光（LIF）。此外，模型的敏感性模拟使用MCM耦合到一个代表性的吸收性气体气溶胶分区纳入本研究结果的参数化将进行调查的大气影响SOA的形成，通过非均相吸收的二羰基化合物的城市环境中的芳香族化合物（二羰基化合物的重要来源）已被提出作为关键的城市SOA的来源。这些实验对于量化SOA的关键潜在形成途径至关重要。.