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其环境和健康影响至关重要。然而，尽管过去十年来，尽管大量的不确定性以及对其来源缺乏基本知识，组成（因此）和形成机制，但气溶胶对地球大气的真正影响尚未得到阐明。最近的实验发现表明，有机气溶胶（OA）本质上是次要的，并且可以占周环总气溶胶的显着部分（10-70％）。但是，当前的模型大大低估了SOA（二级有机气溶胶）的生产及其形成速率。轻量挥发物（例如乙二醛（Gly，CH（O）CHO）和甲基乙二醇（MGLY，CH3C（O）CHO）等轻量挥发物的积聚或寡聚反应，这些反应已被证明是全球SOA的潜在重要来源，已被提议证明这种分歧是合理的。由于Alfa-Dicarbonyls，大小，类型（可逆或不可逆）和颗粒形成的机理仍然是重大的问题。该项目的目的是定量证明以下假设：气溶胶中的gly和mgly的异质吸收可以解释模型中缺少SOA的很大一部分。为了解决这一目标，该项目将进行一系列大量的室外室内实验，这些实验将解决以前研究的主要局限性。实验性工作将通过使用主化学机制（MCM）详细的腔室建模来支持。 Gly或Mgly将直接引入室，或者通过OH +炔烃的反应产生的原位。将在高度仪器的欧洲光电反应器（Euphore）中进行天然太阳辐射（Euphore）的天然太阳辐射的存在（和不存在），以研究这些二甲苯化合物的反应性吸收和SOA生长是否是光化学激活（光敏性）和相对湿度取决于的。 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色谱 - 离子陷阱质谱法（LC-MSN）和激光诱导的荧光（LIF）。此外，将进行模型敏感性模拟，使用MCM与吸收性气体对卫星分配的表示形式，从这项研究的发现中纳入参数化，以研究SOA形成的大气含义，通过异质化的二氨基苯二豆次环境（占二氨基环境）的占地含量的含量（均质的杂种环境）的大气含义（城市SOA来源。这些实验对于量化SOA的关键潜在形成途径至关重要。。