北京特殊时段大气细粒子和超细粒子数浓度谱观测及变化特征分析

发布时间：2018-04-17 21:21

本文选题：大气细粒子和超细粒子 + 数浓度谱分布　；参考：《中国科学技术大学》2016年博士论文

【摘要】：在快速的城市化发展进程中,以北京市为代表的我国大部分城市地区正面临严重的大气颗粒物污染,大气细粒子和超细粒子会降低大气能见度、威胁人类健康、影响生态环境。近年来,北京等地一直致力于改善能源结构、治理燃煤污染、控制机动车排放以缓解大气颗粒物污染状况,在一些国际重大活动举办的特殊时段更是采取严格的临时性减排措施。对大气颗粒物数浓度谱进行长期观测和深入分析,可以为大气颗粒物污染现状评价、大气颗粒物控制策略的制定提供科学依据。为此,本文基于2008年北京奥运会、2014年亚太经济合作组织会议(APEC)和2015年抗战胜利70周年阅兵活动等特殊时段外场观测实验中获得的北京大气颗粒物物理特性资料,深入研究了特殊减排时段北京大气细粒子和超细粒子数浓度谱分布统计特征和变化规律。(1)分析了特殊减排时段前后北京大气颗粒物数浓度谱分布及区域PM2.s分布变化特征,为临时性减排措施的实施效果提供了有效的科学评估。奥运、APEC和阅兵期间北京大气颗粒物总数浓度分别为(6.0±3.1)×103cm-3,(4.7±3.2)×103cm-3和(6.1±3.2)×103cm-3,相比历次减排之前,积聚模态(0.1-1μm)颗粒物数浓度降幅最显著,分别降低40%、49%和48%。奥运、AEPC和阅兵期间北京本地PM2.5分别下降了52%、60.5%和72.3%。APEC期间和阅兵期间,北京周边(京津冀13个城市)PM2.5平均浓度整体降幅为40.0%和59.0%。(2)分析了历次减排时期北京及周边大气颗粒物分布特征差异及其影响因素,为今后区域减排措施制定提供科学建议。奥运、APEC和阅兵三时段,北京城区及周边区域减排控制效果不断提升,与减排指导方针的改善、气象条件以及季节水平有密切关系。北京及其周边近年来不断推进和强化区域联防合作,促进了区域减排效果的提升；APEC和阅兵时段良好的气象条件是减排效果的有利推手；秋季北京大气颗粒物背景浓度平均高于夏季水平,是APEC时段积聚模态颗粒物控制效果低于奥运和阅兵时段的主要原因。(3)分析了北京2015年夏季和冬季大气颗粒物主要来源及数浓度谱分布特征。夏季西南方向的区域输送对爱根核模态和积聚模态颗粒物浓度存在一定贡献,冬季局地排放对爱根核模态和积聚模态颗粒物浓度贡献很大。冬季颗粒物数浓度比夏季高44.7%,主要集中在爱根核模态。冬季一次排放的爱根核模态颗粒物对灰霾的形成有重要的贡献。(4)分析了特殊减排时段北京新粒子生成事件变化规律,进一步认识北京大气新粒子生成和增长规律。减排措施的实施有利于新粒子生成事件的发生,新粒子生成和有效增长对大气背景颗粒物浓度产生积极贡献，当大气背景颗粒物浓度足够高(超过10000 cm-3)时,新粒子生成受到背景颗粒物的抑制。凝结增长对颗粒物增长的贡献优先于碰并增长,颗粒物总数浓度的迅速降低(大于50cm-3min-1,)与GMD和CS、CoagS相关性的降低(低于50%)是碰并增长对颗粒物增长过程贡献的重要标志。另外,北京大气新粒子不仅来源于本地生成,区域输送的成核前体物引发的“烟羽”型成核也存在明显贡献。
[Abstract]:In the city of rapid development process, taking Beijing city as the representative of the majority of China's city area is facing serious atmospheric particulate pollution, atmospheric fine particles and ultrafine particles will reduce visibility, a threat to human health, affecting the ecological environment. In recent years, Beijing and other places have been committed to improving the energy structure, coal pollution governance control of vehicle emissions, to alleviate the pollution of atmospheric particulate matter, special sessions held in some major international activities is strictly temporary emission reduction measures. On particle number concentration spectrum for long-term observation and in-depth analysis, for the status quo of particulate air pollution assessment, atmospheric particulate control and provide scientific basis for making strategy. Therefore, this paper is based on the 2008 Beijing Olympic Games, the 2014 Asia Pacific Economic Cooperation (APEC) and the 2015 victory 70th anniversary parade activities such as a special period of time Atmospheric particle physical properties data of Beijing for field observation experiment, in-depth study of the special emission reduction period of Beijing atmospheric fine particles and ultrafine particle number concentration spectrum distribution characteristics and variation law. (1) analysis of the special period before and after the reduction of atmospheric particulates in Beijing number concentration distribution and regional distribution characteristics of PM2.s, provides scientific assessment of effective implementation effect for the temporary emission reduction measures. During the Olympics, APEC and parade Beijing total atmospheric particulate concentration respectively (6 + 3.1) * 103cm-3 (4.7 + 3.2) * 103cm-3 and (6.1 + 3.2) * 103cm-3, compared to the previous reduction before the accumulation mode (0.1-1 m) the most the particle number concentration decreased significantly, decreased by 40%, 49% and 48%. AEPC during the Olympic Games, and parade in Beijing local PM2.5 were decreased by 52%, 60.5% and 72.3%.APEC and during the parade, around Beijing (Beijing Tianjin and Hebei 13 city average) PM2.5 The concentration of the overall decline of 40% and 59.0%. (2) analysis of the previous period in Beijing and the surrounding emission factors of atmospheric particulates distribution difference and its influence, to provide scientific suggestions for future regional emission reduction measures making. The Olympic Games, APEC and three time parade, Beijing city and the surrounding area emission reduction control effect of continuous improvement, and the improvement of emission reduction guidelines and there is a close relationship between weather conditions and seasonal level. In and around Beijing in recent years to promote and strengthen regional defense cooperation, promote regional emission reduction; APEC and good weather conditions during the parade is the favorable promoter reduction effect; Beijing autumn background atmospheric particulate concentration in summer was higher than average level, is the main reason for the APEC period the accumulation mode particles below the control effect of the Olympic Games and the parade time. (3) analysis of Beijing during the winter of 2015 the main source of atmospheric particulate matter And the number concentration spectrum distribution characteristics. The summer southwest regional transport has certain contribution to the Aitken mode and accumulation mode particle concentration in winter, a great contribution to the local emission Aitken mode and accumulation mode particles. The particle number concentration in winter than in summer 44.7%, mainly concentrated in the Aitken mode Aitken mode particles. From a winter emissions have important contributions to the formation of haze. (4) analysis of the special emission reduction period Beijing new particle formation change event, further understanding of Beijing atmospheric new particle formation and growth law. The implementation of emission reduction measures is favorable for the development of new particle formation events, new particle formation and growth have a positive contribution on the background of atmospheric particulate matter concentration, when the atmospheric background particle concentration is high enough (over 10000 cm-3), a new particle formation is inhibited by background particles condensation growth. The growth of particles with preferential growth in touch and rapidly, reduce the total number of particles concentration (greater than 50cm-3min-1) with GMD and CS, reduce the correlation of CoagS (less than 50%) is an important symbol of growth and contribution to the process of touching particles. In addition, the new Beijing atmospheric particles not only from the local generation the regional transport of nucleation precursor caused by the "plume" nucleation also has the obvious contribution.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X513;X831

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