河北省涞水县大气颗粒物单颗粒分析表征及来源识别

为了解河北省涞水县颗粒物污染特征,采用单颗粒分析技术扫描电镜-X射线能谱法和气团后向轨迹分析技术对该县2015年3个典型污染时段〔即正常管控、严格管控（2015年阅兵期间）及发生严重颗粒物染污〕采集的7个大气颗粒物样品进行了分析表征和来源解析.共测量了1 506个粒径≥0.5 μm的单颗粒,其中粒径小于2.5 μm的颗粒占98%以上,测量结果揭示了细颗粒污染特征.结果表明:①碳质颗粒为主要颗粒物种类,其检出数目占比在90%以上.②非供暖期严格管控时段,当地居民日常生活产生的球形碳质颗粒检出数目占比最高.③非供暖期正常管控时段,机动车排放的碳质集合体颗粒检出数目占比最高,交通污染贡献最大.④供暖期球形碳质颗粒检出数目占比最高,含硫颗粒检出数目占比相对增加,燃煤的贡献最大.3个采样时段48 h气团后向轨迹分析结果表明,在空气质量良好、颗粒物污染水平较低的情况下,影响研究区域空气质量的主要是本地源;雾霾天气（处于严重颗粒物污染时段）时,西南方向外来源和本地源共同构成研究区域的颗粒物污染状态.      

Dry deposition of PM10 over the Yellow Sea during Asian dust events from 2001 to 2007

Dry deposition velocities and fluxes of PM10during Asian dust events over the Yellow Sea from 2001 to 2007 were investigated using observation data in Qingdao, China and Jeju, Korea. The dry deposition velocities of PM10 during dust events over the Yellow Sea ranged from 0.19 to 8.17 cm/sec, with an average of 3.38 cm/sec. Dry deposition fluxes of PM10during dust events over the Yellow Sea were in the range of 68.5–2647.1 mg/(m2·day), with an average of 545.4 mg/(m2·day), which is 2–10 times higher than those reported by other studies for both dust and non-dust periods. It was estimated that 2.6 × 1011–48.7 × 1011g dust particles deposit to the Yellow Sea during dust events through dry deposition every year. Compared with the results in previous studies, it was found that the dry deposition of PM10over the Yellow Sea during dust events in the years with high frequency of dust could account for a large or overwhelming fraction of the annual total dry deposition. Backward air mass trajectory analysis showed that dust events influenced Jeju mainly originated from the desert regions located in Mongolia and Inner Mongolia, China. There were 119 backward trajectories influenced both Qingdao and Jeju during 15 dust events from 2001 to 2007, accounting for 61.3% of the total trajectories of 194, indicating that Qingdao and Jeju were usually on the same pathway of dust transport downwind from source areas.     

Intra‐individual variability in job complexity over time: Examining the effect of job complexity trajectory on employee job strain

Drawing on gestalt characteristics theory, we advance the literature on the effect of job complexity on employee well‐being by considering intra‐individual variability of job complexity over time. Specifically, we examine how the trend, or trajectory, of job complexity over time can explain unique variance of employee job strain. Across two longitudinal data sets, we consistently find that, with the average level of job complexity during a given period held constant, a positive job complexity trajectory (i.e., an increasing trend in complexity) is associated with higher employee job strain. Based on job‐demand‐control theory and the exposure‐reactivity model, we further establish that job autonomy and employee emotional stability jointly moderate the relationship between job complexity trajectory and employee job strain. Specifically, for employees with high emotional stability, job autonomy mitigates the job strain brought by positive job complexity trajectory, whereas for employees with low emotional stability, job autonomy does not help to reduce the adverse effect of the increasing trend. These findings not only contribute to extend the understanding of the job complexity – strain relationship, but also suggest a promising, dynamic avenue to study the effects of work characteristics on employee well‐being as well as other outcomes. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis and Case Study of Duststorms in the Beijing Area

Dust weather conditions with strong wind often occur in Beijing during spring. The number of duststorms in Beijing has declined since 1954. In the last two years, however, the number of duststorms in Beijing has increased drastically due to frequent cold air movements and the deteriorated ecological environment. The heaviest duststorm in the last decade in Beijing occurred on 6 April 2000. It was caused by the development of a high-level small trough along with strong northwest wind behind a large trough that moved eastward and developed a strong cold air system. A non-hydrostatic meso-scale numerical model (MM5) gave a good forecast to the duststorm's major features and movement. Simulated results showed that there was a strong vertical ascending motion with a strong positive vorticity center in mid and low level. The mesoscale structure's formation and development and movement were consistent with the passage and moving direction of the duststorm. At the same time, the trajectories of air particles during this duststorm event and another case (on 27 March 2000) were estimated and analyzed, which had the comparable results with the real situation and the trajectory monitored by meteorological satellite. The trajectories analysis could help us study the transport track and sand source to some extent.     

1990~2020年阿克苏河流域土地利用碳排放时空轨迹与影响因素

土地利用变化会导致不同类型碳源和碳汇功能变化,是碳排放的关键来源.从土地利用变化的角度开展阿克苏河流域碳排放及其影响因素研究,对于促进流域山水林田湖草沙冰一体化保护修复、助力碳达峰与碳中和目标实现具有重要意义.基于1990~2020年的4期土地利用数据与同期社会经济数据,测算土地利用碳排放总量,探究土地利用碳排放时空轨迹及其影响因素.结果表明:①1990~2020年,耕地、林地、建设用地和未利用地整体呈增加趋势,草地和水域呈减少态势.土地利用类型空间变化特征主要表现为草地、未利用地转换为耕地;②1990~2020年流域净碳总排放量呈现持续上升趋势,累计增加了14.78×10⁴ t,耕地面积增加是引起流域净碳排放量增长的关键因素;③流域土地利用碳排放量空间上呈中间高四周低的分布格局,净碳排放量显著变化区域主要分布在温宿县南部、阿克苏市、阿瓦提县及阿拉尔市;④人类活动对土地利用碳排放驱动作用最强且其影响由东部向西部逐渐增大,年均气温对土地利用碳排放影响贡献主要集中在阿克苏市东部和阿瓦提县北部,年均降雨量对温宿县北部和阿合奇县西部的抑制作用较强.     

基于后向轨迹模式对北京市PM2.5来源的探讨

近年来中国经历了数次大范围雾霾天气,北京等多个城市更是遭遇连续雾霾。造成雾霾天气的主要污染物PM_2.5又称细颗粒物。为了进一步治理北京雾霾,为制定政策提供依据,须了解北京地区PM_2.5的来源。本文基于后向轨迹模式并结合PM_2.5浓度计算了2015年9月1日0：00至2016年8月31日23：00以北京为起始点,向后推算48小时的轨迹,并结合轨迹聚类分析法、潜在源贡献因子法（PSCF）、浓度权重轨迹分析法（CWT）等,探讨北京地区PM_2.5的来源。结果表明：模拟的后向轨迹经过聚类分析可分为6类,其中来自内蒙古西部的轨迹最多,来自西北、北西北方向的轨迹次之,来自西西北方向且在京津冀地区停留一段时间的轨迹占比最小,来自河北、山东、河南的交接地区及河北的沿海地区的轨迹占比也较小。其中来自内蒙古西部地区及河北、山东、河南交界地区的两类轨迹对北京的空气质量有较大的影响,是北京PM_2.5污染的主要潜在源区;来自北西北方向及河北的沿海地区两类轨迹的气团最为清洁,为北京带来良好的天气;来自西北及西西北方向的部分轨迹对应的PM_2.5浓度严重超标,说明来自此方向的气团对北京的空气质量也有一定的影响。     

空气质量模型及参数选用导则

本研究是为了在大气污染物浓度估算中提供一个可以接受的技术分析的共同尺度,将所需用的空气质量模式分为三个等级。第一级模式作为在制定大气环境管理的法规和政策时主要应用的模式。第二、三级模式作为研究级模式。本文详细介绍了第一级模式的主要应用原则,简要介绍了第二、三级模式。      

华北南部重污染城市周边区域二次气溶胶的化学特征及来源解析

为探究华北南部地区重污染城市邯郸市北部地区冬季大气颗粒物的化学组分及来源,于2020年11月23日至12月12日采集了 PM1 和PM2.5样品并进行了分析.观测期间日平均ρ(PM1)和ρ(PM2.5)分别为114.53 μg·m-3和124.25μg·m-3,PM1/PM2.5比值的变化范围为83.3％～95.3％,...     

Dominance in feeding territories relates to foraging success and offspring growth in brown skuas <Emphasis Type="Italic">Catharacta antarctica lonnbergi</Emphasis>

Territoriality should lead to strict dominance, as territory holders typically control access to resources and exclude others from their use. In feeding territories, dominance should be reflected in foraging success and ultimately in reproduction differences; however, these successive links have rarely been made explicit. Therefore, we investigated a population of brown skuas Catharacta antarctica lonnbergi, in which only part of the breeding population occupied feeding territories within penguin colonies. We identified the dominance hierarchy and determined the foraging success of the participants in fights for access to penguin carcasses within the territories. Furthermore, we monitored offspring growth from parents with and without feeding territories. Our results indicated a clear dominance hierarchy with territorial birds in their own territory dominating over territorial breeders from other territories, non-territorial breeders and non-breeding birds. However, territory owners could not completely exclude others from access to food. Foraging success was positively related to dominance scores: The dominant territory owners received 63% of a carcass, whereas non-territorial pairs could get less than 10%. The link between foraging success and offspring development was less clear: Although male chicks of non-territorial parents suffered from lower growth rates and, thus, delayed fledging, there were no such differences in female chicks. Territoriality in skuas did not imply a complete occupation of food, but guaranteed optimal growth conditions for offspring. Non-territorial individuals were forced to search for alternative resources, and the restricted access to the preferred food resulted in inferior conditions for offspring development, making this foraging strategy less rewarding.