Consumption of reactive halogen species from sea-salt aerosol by secondary organic aerosol: slowing down the bromine explosion
Consumption of reactive halogen species from sea-salt aerosol by secondary organic aerosol: slowing down the bromine explosion
复制标题
二次有机气溶胶消耗海盐气溶胶中的活性卤素：减缓溴爆炸
DOI：
10.1071/en14226
复制
发表时间：
2015
影响因子：
4.3
通讯作者：
Buxmann J
中科院分区：
文献类型：
--
作者：
Buxmann J
二次有机气溶胶和海盐气溶胶是全球气溶胶的主要组成部分，并影响反应性卤素的释放，从而影响空气质量和人类健康。在本研究中，通过室内实验量化了三种不同类型的二次有机气溶胶对模拟盐气溶胶中活性卤素物种的损失，并借助数值模型进行了研究。损失率可以纳入大气化学模型，有助于量化自然界的卤素收支。二次有机气溶胶（SOAs）与环境中共存的活性溴（如BrO、Br2、HOBr）之间的相互作用尚未得到很好的理解，目前的化学模型也未将其纳入其中。本研究量化了在聚四氟乙烯烟雾室中臭氧分解三种前体（α-蒎烯、儿茶酚或愈创木酚）引起的SOAs引起的人工盐气溶胶中溴释放的猝灭，并将其纳入化学盒模型。模型模拟在没有SOA前体的空白实验中表现良好，通过微分光学吸收光谱检测捕获了BrO的形成。SOA表面的一阶BrO损失率为0.001s-1，代表模型中包含的整体有效Brx（总无机溴）损失。模型在时间和幅度上与最大混合比基本一致，但在具体形状上存在差异。在有机物存在的情况下，可以观察到反应性OClO的形成，但该模型无法再现。根据目前的知识，正如模型所预测的那样，大多数无机氯在有机物存在时将以HCl的形式存在。为了重现SOA存在的净效应，估计α-蒎烯、儿茶酚和愈创木酚在SOA表面对活性溴的有效吸收系数分别为0.01、0.01和0.004。吸收系数现在可以纳入方框模型，甚至全球模型，在这些模型中，溴物种的汇被认为是不充分的。
Environmental context Secondary organic aerosols together with sea-salt aerosols are a major contribution to global aerosols and influence the release of reactive halogens, which affect air quality and human health. In this study, the loss of reactive halogen species from simulated salt aerosols due to three different types of secondary organic aerosols was quantified in chamber experiments and investigated with the help of a numerical model. The loss rate can be included into chemistry models of the atmosphere and help to quantify the halogen budget in nature. Abstract The interaction between secondary organic aerosols (SOAs) and reactive bromine species (e.g. BrO, Br2, HOBr) coexisting in the environment is not well understood and not included in current chemistry models. The present study quantifies the quenching of bromine release from an artificial salt aerosol caused by SOAs from ozonolysis of three precursors (α-pinene, catechol or guaiacol) in a Teflon smog chamber and incorporates it into a chemical box model. The model simulations perform very well for a blank experiment without SOA precursor, capturing BrO formation, as detected by differential optical absorption spectrometry. A first-order BrO loss rate of 0.001s–1 on the surface of SOA represents the overall effective Brx (total inorganic bromine) loss included in the model. Generally, the model agrees with the maximum BrO mixing ratio in time and magnitude, with some disagreements in the exact shape. Formation of reactive OClO was observed in the presence of organics but could not be reproduced by the model. According to current knowledge, most inorganic chlorine would be in the form of HCl in the presence of organics, as predicted by the model. In order to reproduce the net effects of the presence of SOA, the effective uptake coefficients of reactive bromine on the SOA surface are estimated to be 0.01, 0.01 and 0.004 for α-pinene, catechol and guaiacol respectively. The uptake coefficient can now be incorporated into box models and even global models, where sinks for bromine species are thought to be inadequately represented.