Impact of dust on tropospheric chemistry over polluted regions: a case study of the Beijing megacity
Impact of dust on tropospheric chemistry over polluted regions: a case study of the Beijing megacity
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沙尘对污染地区对流层化学的影响：以北京特大城市为例
DOI：
10.5194/acp-10-3855-2010
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发表时间：
2009-09
影响因子：
6.3
通讯作者：
er, R.
中科院分区：
文献类型：
--
作者：
Zhu, S.;Ma, J.;Lawrence, M. G.;Butler, T.;S;er, R.
抽象的。盒模型 MECCA（有效计算大气化学的模块）通过纳入矿物气溶胶表面发生的详细异质化学而得到扩展。该模型用于研究沙尘输送到污染地区时对对流层光化学的影响，重点以北京为例。通过模型中四个不同的交换率系数 Kt 描述了不同的假设传输速率，分析了气体异质去除对粉尘的影响。与灰尘一起，具有北京上风区特征的微量气体水平的气团也以相同的速率（Kt）输送。许多气体都会产生重大影响，包括 Ox (O3+O(3P))、NOx (NO+NO2) 和 OH。由于粉尘的异质反应，Ox 日平均混合比降低。变化范围为 -2.5 至 -18.4 nmol mol−1，并且与逆风气团更快混合时变化更大（即更大的 Kt）。这转化为 Ox 的较大相对变化，范围从 -44% 到 -55%，具体取决于 Kt。通过假设所有光解速率人为降低 50%，还可以估计灰尘通过干扰污染区域的光解速率而产生的影响。此外，还评估了由于吸收系数的不确定性而导致的结果的不确定性。研究发现，对于所有异质去除的气体，自去除导致最大的不确定性（例如，O3为-49%，NO2为-76%，HNO3为-47%，HCHO为-92%，CH3OH为-64%，SO2为-93%）。人们发现 NO2 的异质去除特别重要，因为它不仅导致其本身，而且导致 OH (340%) 和 HO2 (365%) 产生显着的不确定性。此外，HCHO和O3的异质去除率对OH浓度也有更深远的影响（分别导致-55％和45％的变化），并且HCHO的异质去除导致HO2浓度的不确定性为-38％。由于 MECCA 缺少芳香族化合物和其他较高 VOC 物质的氧化机制，MECCA 的局限性也得到了考虑，并表明在定量结果中具有潜在的重要性，尽管不太可能改变本研究的定性结果。
Abstract. The box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) is extended by incorporating detailed heterogeneous chemistry occurring on mineral aerosol surfaces. The model is used to investigate the impact of dust on tropospheric photochemistry, when the dust is transported to a polluted region, focusing on the example of Beijing. The impacts of dust via heterogeneous removal of gases are analyzed for different hypothetical transport rates, which are described by four different exchange rate coefficients Kt in the model. Along with the dust, airmasses with trace gas levels characteristic for regions upwind of Beijing are transported with the same rate (Kt). Substantial impacts are found for many gases, including Ox (O3+O(3P)), NOx (NO+NO2) and OH. The Ox daily average mixing ratio decreases due to heterogeneous reactions on dust. The change ranges from −2.5 to −18.4 nmol mol−1, and is larger for faster mixing with upwind air masses (i.e. greater Kt). This translates into a large relative change in Ox, ranging from −44% to −55%, depending on Kt. By assuming an artificial 50% decrease of all photolysis rates, the impacts of dust via perturbation of the photolysis rates in the polluted region are also estimated. Furthermore, the uncertainties in the results due to the uncertainties in the uptake coefficients are evaluated. It is found that for all gases which are heterogeneously removed, the self-removal results in the largest uncertainty (e.g. −49% for O3, −76% for NO2, −47% for HNO3, −92% for HCHO, −64% for CH3OH and −93% for SO2). The heterogeneous removal of NO2 is found to be particularly important, because it results in significant levels of uncertainty not only for itself, but also for OH (340%) and HO2 (365%). Moreover, the heterogeneous removal rates of HCHO and O3 also have farther-reaching effects on the OH concentration (resulting in changes of −55% and 45%, respectively), and the heterogeneous removal of HCHO results in an uncertainty of −38% in the HO2 concentration. The limitations of MECCA due to its missing oxidation mechanism for aromatics and other higher VOC species has also been considered, and shown to be potentially important in the quantitative results, though not likely to change the qualitative results of this study.
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影响因子：
5.2
作者：
A. E. Michel;C. Usher;Vicki H. Grassian
通讯作者：
A. E. Michel;C. Usher;Vicki H. Grassian
DOI：
10.1175/1520-0450(1994)033
发表时间：
1994-04
期刊：
Journal of Applied Meteorology
影响因子：
--
作者：
Julxo C. Calvo;J. Gregory
通讯作者：
Julxo C. Calvo;J. Gregory
影响因子：
--
作者：
B. Heikes;A. Thompson
通讯作者：
B. Heikes;A. Thompson
影响因子：
6.3
作者：
M. Ullerstam;M. Johnson;R. Vogt;E. Ljungström
通讯作者：
M. Ullerstam;M. Johnson;R. Vogt;E. Ljungström
影响因子：
6.3
作者：
Mingjin Tang;J. Thieser;Gerhard Schuster;John N. Cowley
通讯作者：
Mingjin Tang;J. Thieser;Gerhard Schuster;John N. Cowley