Factors contributing to haze and fog in China
Factors contributing to haze and fog in China
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DOI：
10.1360/972013-150
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发表时间：
2013-05
影响因子：
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通讯作者：
Xiaoye Zhang;Junying Sun;Yaqiang Wang;Weijun Li;Qiang Zhang;Weigang Wang;J. Quan;G. Cao;
中科院分区：
文献类型：
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作者：
Xiaoye Zhang;Junying Sun;Yaqiang Wang;Weijun Li;Qiang Zhang;Weigang Wang;J. Quan;G. Cao;
本文分析了霾、气溶胶与气象条件的关系，分析了气溶胶粒子的化学组成和来源，并提出了防治对策建议。中国目前的霾和雾都与大气气溶胶负荷和天气条件有关。二次气溶胶的形成和变化是华东地区灰霾天气的主要特征，在气溶胶总量中占主导地位，且受气象条件的影响较大。在华北平原，这是遭受强烈的霾和雾，二次有机气溶胶被发现有类似的作用，如硫酸盐，有助于气溶胶质量在新的粒子形成和老化阶段。在相对湿度约70%时，有机气溶胶与无机气溶胶混合形成吸湿粒子较早，但吸湿粒子的吸湿增长因子较小。吸湿性气溶胶颗粒也会使中国PM2.5质量监测在高相对湿度阶段呈现出不切实际的高浓度。这些颗粒中约70%内部混合有两种或三种不同的气溶胶成分。大多数矿物颗粒都被可见的涂层覆盖，包括飞灰，烟灰和金属颗粒，导致在其表面形成更多的二次气溶胶。这使中国的雾霾形成复杂化。在气溶胶粒子浓度较高的情况下，低云中观测到的相对较小的云滴数量要多于高云;在污染较轻的地区，气溶胶粒子对云微物理过程的影响是不同的。在低过饱和度下，大于150 nm的吸湿粒子大多数形成云凝结核（CCN），气溶胶化学成分对CCN激活有显著影响。除南亚城市外，中国的气溶胶浓度相对于世界其他地区都很高。这些粒子的形成条件复杂，并与云相互作用，导致我国目前的霾和雾都不是自然现象。霾和雾减少了地面辐射，使大气更加稳定，导致气溶胶不断凝结、凝结、积累，更多的CCN活化，导致霾-雾事件的严重性和持续性。2013年1月6 - 16日华东地区持续性大雾天气是由高浓度气溶胶和特殊的静态天气条件共同作用的结果。我们需要对中国气溶胶减排的复杂性和预期有充分的科学判断。政府需要做出明智的决定并执行法律来维护人民的健康，但当我们努力实现经济增长时，这并不容易。控制气溶胶污染源没有简单的办法，但政府应不遗余力地减少气溶胶及其前体气体的排放。区域污染控制也非常关键;中央政府需要执行强有力的政策和协议，推动省级领导人做出必要的改变，以确保更好的空气质量和人民的生活质量。
We assess the relationship among haze-fog, aerosol and meteorological conditions, and analyze the chemical compositions and sources of aerosol particles, as well make some suggestions for aerosol control strategy. Present-day haze and fog in China are both dependent on atmospheric aerosol loading and weather conditions. The secondary aerosol formation and changes, which dominate the total aerosol mass and are highly influenced by meteorological conditions, characterized the regional haze feature in East China. In the Huabei Plain, which suffers from intense haze and fog, secondary organic aerosols are found to have similar role like sulphate, contributing to aerosol mass during both new particle formation and aging stages. The organic aerosol mix with inorganic ones to form hygroscopic particles earlier at ～70% relative humidity (RH), but which have a small hygroscopic growth factor. The hygroscopic aerosol particles would also make the PM2.5 mass monitoring at China exhibiting unrealistic high concentration under high RH stage. About 70% of these particles are internally mixed with two or three different aerosol components. Most mineral particles are covered with visible coatings, including fly ash, soot and metal particles, leading to have more secondary aerosol formed on their surface. This complicates haze formation in China. Under high aerosol particle concentrations, greater numbers of cloud droplets with relative small-size are observed in low clouds relative to high clouds; and the associated aerosol impact on cloud microphysical processe is different in less polluted areas. At low supersaturation most of hygroscopic particles larger than 150 nm form cloud condensation nuclei (CCN), and the impact of aerosol chemical composition on CCN activation is significant. There is a high aerosol concentration in China relative to other areas in the world, except for urban South Asia. These particles form under complex conditions and interact with clouds, resulting that present-day haze and fog in China both are not natural phenomenon. Haze and fog reduces surface radiation, making the atmosphere more stable, resulting in continuous coagulation, condensation, accumulation of aerosol, and more CCN activation, leading to serious and maintained haze-fog events. The heavy and persistent haze-fog between 6 and 16 January 2013 in East China was caused by both high aerosol loading and singular static weather conditions. We need to have adequate scientific judgment on the complexity and expectation of aerosol emission reduction in China. The government needs to make informed decisions and implement laws to maintain the health of its people, but this is not easy when we strive for economic growth. There is no easy solution to control aerosol sources, but the government should spare no effort to cut aerosol and their precursors gas emission. Regional pollution control is also very critical; a strong policy and protocol needs to be enforced by the central government to drive provincial leaders to make the necessary changes to ensure better air quality and quality of life for the population.