Effect of air masses motion on the rapid change of aerosols in marine atmosphere

The impact of air masses motion on marine aerosol properties was investigated using an on-board single particle mass spectrometer(SPAMS) deployed for the determination of single particle size resolved chemical composition over Southeast China Sea. Two aerosol blooms(E1 and E2) were observed during the cruise. High average particle number count occurred in E1(7320), followed by E2(5850), which was more than 100–150 times of the average particle number count during normal periods. Particles were classified as four major sources, including continental source, shipping source, marine source, and transport source based on the mass spectral similarity. Transport source was identified as those particles with high particle number count occurred only during aerosol bloom period. Three sub-types of EC-Ca, OC-Ca, and Al-rich were classified as transport source.EC-Ca was the dominant particles of the transport source, accounting for more than 70%of the total particles in aerosol bloom events. A uni-modal size distribution in the size range of 0.1–2.0 μm was observed during normal period, while a bimodal distribution with a tiny mode(0.3 μm) and a coarse mode between 0.4 and 0.6 μm was present during aerosol bloom. The variation of aerosol source is consistent with air masses back trajectories, for the reason that most of the long-range air trajectories are from the ocean,while short air trajectories originate in the continental regions, which means that air masses have a significant impact on the aerosol physical–chemical properties along their tracks.     

北京地区大气温湿廓线对气溶胶垂直分布的影响

目的分析北京地区大气温湿廓线对气溶胶垂直分布的影响。方法利用北京地区2017年9月至2018年8月每日两次(08时和20时)的气象探空、地面PM_(2.5)浓度和气溶胶激光雷达消光系数资料,分析不同污染条件下大气温湿廓线与气溶胶消光系数廓线的关系。结果地面PM_(2.5)浓度和210m气溶胶消光系数的相关系数达到0.77。春季、秋季和冬季污染条件下的近地面消光系数约是清洁条件下的5倍,夏季污染条件下的近地面消光系数约是清洁条件下的3倍。相比清洁条件下,污染条件下各季节的大气温度垂直递减率偏小,并且低层大气相对湿度偏大。结论大气温度廓线代表大气层结稳定性,影响气溶胶的扩散高度,而相对湿度廓线与气溶胶吸湿增长密切相关,两者对气溶胶消光系数的垂直分布都有重要影响。     

沈阳工业区夏季VOCs组成特征及其对二次污染形成的贡献

利用2019年和2020年夏季沈阳市工业区大气挥发性有机物(VOCs)的观测数据,研究沈阳市夏季工业区大气VOCs的组成特征并初步判断其来源,并利用最大增量反应活性(MIR)和气溶胶生成系数(FAC)法分别估算该地大气VOCs的臭氧生成潜势(OFP)及二次有机气溶胶生成潜势(AFP).结果表明,观测期间沈阳市工业区ρ(总VOCs)平均值为41.66μg·m^-3,烷烃、烯烃、芳香烃和乙炔分别占总VOCs浓度的48.50%、 14.08%、 15.37%和22.05%.浓度排名前10的物种累计占总VOCs浓度的69.25%,其中大部分为C2～C5的烷烃,还包括乙炔、乙烯和部分芳香烃.总VOCs整体上呈现出早晚浓度高、中午浓度低的日变化特征,峰值分别出现在06:00和22:00,11:00～16:00处于较低水平.由甲苯/苯(T/B)和异戊烷/正戊烷的比值判断工业区主要受机动车尾气排放、溶剂使用、燃烧源和LPG/NG的影响.工业区大气VOCs的总AFP为41.43×10^-2μg·m^-3,其中芳香烃的贡献最大;总OFP贡献值为1...     

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.     

Chemical characteristics of aerosol particles (PM2.5) at a site of Horqin Sand-land in northeast China

Introduction Soil dust derived from the w ind erosion process in arid and sem i-arid region is an im portant factor on the clim ate forcing(Tegen etal., 1996; Sokolik and Toon, 1996). D esert regions in East A sia w ere considered as the m ajor sources fo…     

有机气溶胶组分对六氯苯光解的影响

以高压汞灯为光源,分别研究了六氯苯在正己烷和邻苯二甲酸二异辛酯(DIOP)为有机气溶胶表层模拟介质时的光解,发现六氯苯在正己烷和DIOP中的光解半衰期分别约为<5 min和5 h,相差70倍以上.研究发现蒽醌和甲氧酚类气溶胶组分对六氯苯的光解具有光敏化作用,其反应机制可能分别为能量转移和抽氢反应.六氯苯光解的主要产物是五氯酚.     

我国不同矿物气溶胶源区物质的物理化学特征

在我国不同的矿物气溶胶源区进行采样分析的结果表明,源区气溶胶物质的物理化学特性相差很大.黄土的颗粒最细,91%的黄土颗粒可以形成矿物气溶胶进行长距离输送;沙土较粗,只有15%的沙尘颗粒可以形成矿物气溶胶;2个煤灰样品的粒径差异较大,抚顺煤灰中＜74μm的颗粒高达39%,而呼和浩特煤灰只有7%.不同粒径颗粒的化学分析结果表明,微量元素在细颗粒上有较高的富集.黄土与沙漠土壤的细颗粒的化学性质十分相似,同煤灰的化学性质完全不同,其常量元素与A1的比值(E/Al)十分接近,而且与深海沉积物粘土中的比值(E/A1)     

西太平洋海域海水和雨水的化学特征

本工作测定了西太平洋海域中海水、海水悬浮物和海面上雨水的元素组成和浓度。通过富集因子的计算,探讨海面上雨水中微量元素的富集程度及其来源,讨论了海面上气溶胶粒子大小与洗出因子的关系,结果表明不同质量粒径大小的微量元素在公海上具有相似的洗出因子。     

Associations of trace elements in aerosol at the south Adriatic coast

We applied statistical methods to the data of a 5-year sampling period to characterize the features of trace elements in airborne particulate matter at the South Adriatic Coast. The analysis of surface soil samples was also performed. The data were processed by cluster analysis, enrichment factor determination and receptor rose statistics. It is shown that the principal element association consists of Fe, Mn and Ti originating from surface material resuspension. Hg and Se were shown to originate from more complex natural and anthropogenic processes. A strong emission source of Cd and Se was identified in the SSE direction.Selected article from the Regional Symposium on Chemistry and Environment Krusevac, Serbia, June 2003, organized by Dr. Branimir Jovancicevic.     

用核子微探针进行单个大气颗粒物的分析

本文对单个大气颗粒物进行了分析研究，用核子微探针对首钢地区单个大气颗粒物进行了扫描分析，用三维等高线法给出了各种元素在一群单个大气颗粒物中的二维分布。从一群单个大气颗粒物中各元素的二维分布可对首钢地区大气污染的特征及来源进行分析研究。