长光路傅立叶变换红外光谱技术研究氯氟烃替代物与氢氧自由基反应速率常数

利用长光路傅立叶变换红外光谱技术（LP－FTIR）,用相对速率方法研究大气中氯氟烃替代物HFC152a（CHF₂CH₃）和HCFC22（CHClF₂）与OH自由基反应速率常数,用紫外光照射O₃和H₂O的方法产生OH自由基。实验测定了700Tor大气压力和常温（298±2k）下的反应速率常数值：k（HFCl52a＋OH）＝（2.90±0.09）×10^－14cm₃·molecule^－1．S^－1,k（HCFC22＋OH）＝（3.80±0.24）×10^－15cm3．Molecule^－1．S^－1,统计误差为2σ     

光电化学法处理水体中腐殖酸的初步研究

结合９０年代欧美学者提出了高级化学氧化过程（Ａｄｖａｎｃｅｄｃｈｅｍｉｃａｌｏｘｉｄａｔｉｏｎｐｒｏｃｅｓｓ，ＡＯＰ）原理，提出了并建立了一套光电化学联用的新用于处理难以生物降解的腐殖酸废水，实验表明，在通电１ｈ加光条件下（Ｉ＝０．２Ａ）总有碳（ＴＯＣ）去除率达到９０％，色度去除率达到９５％。     

利用干酪根固体~(13)C核磁共振法研究下古生界碳酸盐岩的热演化程度

应用固体~(13)C－NMR技术对下古生界,海相碳酸盐岩干酪根的化学组成和结构特征进行研究，提出应用该技术所测算的干酪根结构参数“芳核平均结构尺寸”能较准确地反映碳酸盐岩的热成熟度。首次提出芳核平均结构尺寸与镜质体反射率之间的关系在干酪根的热演化过程中具有“三段式”特征。利用这一成果对华北地区下古生界成熟度进行了测定，与地质背景甚为吻合。     

久效磷对海洋微藻毒性机理的初步研究Ⅲ.超氧化物歧化酶和过氧化物酶活性的变化

报道了久效磷对３种海洋微藻细胞内２种清除活性氧的关键性酶－超氧化物歧化酶和过氧化酶活性的影响。结果显示：１．在久效磷的胁迫下，扁藻和三角褐指藻细胞的超化物歧化酶活性均表现出下降的总变化趋势，而叉鞭金藻细胞的ＳＯＤ活性时而上升，时而下降，在整个胁迫过程中呈现出无规律性的变化。２．随着久铲磷胁迫时间的延长，３种微藻细胞的过氧化酶活性均逐渐下降，表现出相同的变化规律性。     

镉铅对小麦醇脱氢酶(ADH)基因表达影响的初步研究

经过镉，铅４５ｈ污染处理，运用Ｎｏｒｔｈｅｉｎ斑点杂分析和酶活性测定的方法探测萌发期小麦ＡＤＨ酶基因的表达情况。实验结果表明，ＡＤＨ基因表达在ＲＮＡ和酶活性两个层次均有变化，并且呈现相似的变化趋势，反映得金属的影响是来源于基因转录水平。     

京津冀城市群冬季二次PM2.5的时空分布特征

二次组分是造成京津冀城市群冬季PM_2.5污染的重要因素.采用CO示踪法,估算2017～2021年冬季京津冀城市群二次PM_2.5浓度,并分析其时空分布特征,探讨区域二次PM_2.5的影响因素.结果表明,2017～2021年冬季京津冀区域PM_2.5浓度下降趋势明显,河北中南部一次PM_2.5下降幅度最大,二次PM_2.5浓度年际波动平稳,北京和天津二次PM_2.5占比明显高于其他城市.随着污染程度加剧,一次PM_2.5和二次PM_2.5质量浓度均有不同程度的增加,二次PM_2.5占比呈显著增大趋势.与直接测量结果相比,CO示踪法获得的结果偏低,与冬季CO浓度较高,一次PM_2.5浓度高估有关,选取合适的一次气溶胶基准值是改进该方法,获取合理估算值的关键.     

气候变化和人类活动对东部沿海地区NDVI变化的影响分析

植被是陆地生态系统的重要组成部分,特别是在人类活动密集地区,良好的植被覆盖对于维持区域生态环境稳定、增进居民生活福祉和促进社会经济可持续发展意义重大.基于归一化植被指数(NDVI)、气温、降水和太阳辐射数据,采用趋势分析、偏相关分析和残差分析等方法,探究了1982～2019年中国东部沿海地区NDVI时空变化特征及其与气候因子的关系,评估了气候因素和人类活动等非气候因素对NDVI变化的影响.结果表明：(1)1982～2019年研究区NDVI变化趋势具有明显区域性、阶段性和季节性差异,就区域平均而言,2000年以前(第一阶段)的生长季NDVI比2001年以后(第二阶段)增加更快,而两阶段春季NDVI增加速率均为各季节最快;(2)同一阶段NDVI与各气候因子的关系在不同季节存在差异,而同一季节NDVI的主要气候控制因子在不同阶段也不一致,并且NDVI与气候因子的关系具有很大空间差异.总体上,1982～2019年研究区生长季NDVI的增加与气温的持续上升关系紧密,第二阶段降水和太阳辐射的增加也产生了积极作用;(3)相比于人类活动等非气候因素的影响,气候变化对近38年来研究区生长季NDVI变化的...     

Progress in quantitative research on the relationship between atmospheric oxidation and air quality

Atmospheric oxidizing capacity (AOC) is an essential driving force of troposphere chemistry and self-cleaning, but the definition of AOC and its quantitative representation remain uncertain. Driven by national demand for air pollution control in recent years, Chinese scholars have carried out studies on theories of atmospheric chemistry and have made considerable progress in AOC research. This paper will give a brief review of these developments. First, AOC indexes were established that represent apparent atmospheric oxidizing ability (AOIe) and potential atmospheric oxidizing ability (AOIp) based on aspects of macrothermodynamics and microdynamics, respectively. A closed study refined the quantitative contributions of heterogeneous chemistry to AOC in Beijing, and these AOC methods were further applied in Beijing-Tianjin-Hebei and key areas across the country. In addition, the detection of ground or vertical profiles for atmospheric OH·, HO₂·, NO₃· radicals and reservoir molecules can now be obtained with domestic instruments in diverse environments. Moreover, laboratory smoke chamber simulations revealed heterogeneous processes involving reactions of O₃ and NO₂, which are typical oxidants in the surface/interface atmosphere, and the evolutionary and budgetary implications of atmospheric oxidants reacting under multispecies, multiphase and multi-interface conditions were obtained. Finally, based on the GRAPES-CUACE adjoint model improved by Chinese scholars, simulations of key substances affecting atmospheric oxidation and secondary organic and inorganic aerosol formation have been optimized. Normalized numerical simulations of AOIe and AOIp were performed, and regional coordination of AOC was adjusted. An optimized plan for controlling O₃ and PM_2.5 was analyzed by scenario simulation.     

VOC emission caps constrained by air quality targets based on response surface model: A case study in the Pearl River Delta Region, China

Because of the recent growth in ground-level ozone and increased emission of volatile organic compounds (VOCs), VOC emission control has become a major concern in China. In response, emission caps to control VOC have been stipulated in recent policies, but few of them were constrained by the co-control target of PM_2.5 and ozone, and discussed the factor that influence the emission cap formulation. Herein, we proposed a framework for quantification of VOC emission caps constrained by targets for PM_2.5 and ozone via a new response surface modeling (RSM) technique, achieving 50% computational cost savings of the quantification. In the Pearl River Delta (PRD) region, the VOC emission caps constrained by air quality targets varied greatly with the NO_x emission reduction level. If control measures in the surrounding areas of the PRD region were not considered, there could be two feasible strategies for VOC emission caps to meet air quality targets (160 µg/m³ for the maximum 8-hr-average 90th-percentile (MDA8-90%) ozone and 25 µg/m³ for the annual average of PM_2.5): a moderate VOC emission cap with <20% NOx emission reductions or a notable VOC emission cap with >60% NO_x emission reductions. If the ozone concentration target were reduced to 155 µg/m³, deep NO_x emission reductions is the only feasible ozone control measure in PRD. Optimization of seasonal VOC emission caps based on the Monte Carlo simulation could allow us to gain higher ozone benefits or greater VOC emission reductions. If VOC emissions were further reduced in autumn, MDA8-90% ozone could be lowered by 0.3-1.5 µg/m³, equaling the ozone benefits of 10% VOC emission reduction measures. The method for VOC emission cap quantification and optimization proposed in this study could provide scientific guidance for coordinated control of regional PM_2.5 and O₃ pollution in China.     

基于随机森林的南京市PM2.5和O3对减排的响应

自2013年《大气污染防治行动计划》实施后,南京市大气污染有所改善,但仍面临着细颗粒物(PM_2.5)和臭氧(O₃)污染问题.为探究污染物浓度对其前体物减排的响应,获得有效的减排策略,常利用大气化学模式进行多组基于排放扰动的敏感性试验,而这需要消耗大量计算时间和计算资源.应用随机森林算法对2015年大气化学传输模式(GEOS-Chem)模拟结果进行机器学习,高效地预测了南京2019年PM_2.5浓度日均值和日最大8 h臭氧(MDA8 O₃)浓度对不同人为源排放控制情景的响应.随机森林结果表明2019年中国人为排放每减少10%,南京ρ(PM_2.5)季节平均值下降2～4μg·m^-3.当2019年中国人为源减排比例高于20%时,南京ρ(PM_2.5)年均值将低于国家二级限值(35μg·m^-3).若仅对中国地区O₃前体物氮氧化物(NO_x)和挥发性有机污染物(VOCs)同比例减排,反而...