北京市春夏季大气气溶胶的单颗粒分析表征

采集了北京市2000年春夏季大气气溶胶样品5个，采用扫描电镜X射线能谱技术分析大气气溶胶单颗粒约2500个。研究结果表明，沙尘期间，矿物尘是最主要的颗粒物种类，非沙尘期间，北京市大气气溶胶中主要检出矿物尘和含硫颗粒物。夏季随着颗粒物污染的加重，含硫颗粒物的数目百分数增加。是北京市大气颗粒物污染的重要特征。重点讨论了Ca-S颗粒、K-S颗粒和Ca-K-S颗粒三类典型含硫颗粒物的化学组成和粒径分布特征。数目可观的Ca-K-S颗粒以及其他硫酸盐颗粒的生成与相对湿度和云量等气象条件相关，这些颗粒物可能是云中过程的产物。减少SO2排放，减少含硫颗粒物，对于控制北京市的大气颗粒物浓度水平具有重要意义。     

黑碳气溶胶研究进展Ⅰ：排放、清除和浓度

黑碳气溶胶是近几年非常活跃的一个研究课题，因为黑碳气溶胶吸收太阳和地球大气的辐射，对全球气候变暖有重要的影响。中国黑碳气溶胶的排放和浓度比同纬度的高，在全球气候变暖的大背景下，中国黑碳气溶胶一直受到国外的关注。综述了国内外黑碳气溶胶研究的最新进展，受篇幅的限制，文章分两篇，第一篇是黑碳气溶胶的排放、清除和浓度，第二篇是黑碳气溶胶的气候效应和拓展的研究领域。从黑碳排放的估算和大气浓度的测量方法进行描述，列出有关的测量结果，对黑碳气溶胶的排放和大气浓度进行国内外的初步比较分析。还对黑碳气溶胶排放和浓度测量误差进行了讨论，并对今后黑碳气溶胶研究提出了几点建议。     

北京大气气溶胶中硫酸盐的硫同位素组成及其示踪研究

<正>近年来,随着经济快速发展,北京大气污染加剧,雾霾日趋严重。大气气溶胶能够显著影响区域能见度,对一个区域的经济发展和生活质量有较大影响。硫酸盐是大气气溶胶中重要的一部分,尤其是直径小于2.5μm的气溶胶。硫酸盐气溶胶通过改变辐射平衡、温度、降雨和大气动力学而影响气候,同时也能够影响地球辐射收支平衡以及臭氧浓度。硫同位素作为一种示踪剂,在环境科学中得到广泛应用。利用硫同位素技术能够使我们更好地理解硫酸盐气溶胶的来源及其迁移转化机理,对治理和改善大气环境十分必     

IGAC计划大气气溶胶研究进展

ＩＧＡＣ计划大气气溶胶研究进展气溶胶是大气中相对短寿命的、由不同成分组成的、质量和数量浓度都有很大空间变异性的微组分。但是，它们对人类健康、大气质量（能见度、酸沉降）都有很大影响，而且在许多天气和气候过程中起着重要作用。但是有关气溶胶对全球气候的重要...     

基于加密探空观测的成都市一次重霾污染过程中大气边界层气溶胶垂直结构分析

基于2017年1月4日至7日成都市一次重霾污染过程的系留汽艇探测的低层大气气象要素和大气颗粒物垂直探空加密观测资料,分析了大气边界层结构及气溶胶垂直分布。结果表明,此次重霾污染期间,大气边界层昼夜变化特征基本消失。稳定边界层结构出现25次,对流边界层结构仅出现3次,大气边界层结构趋于稳定,边界层高度普遍在700 m以下。霾污染发生、维持及消散阶段大气边界层气溶胶垂直结构具有明显差异。霾污染发生阶段,大气边界层气溶胶粗、细粒子主要集中在300m高度以下,近地面层大气气溶胶粒子累积触发霾污染事件;霾维持阶段,大气颗粒物粒子浓度数垂直方向趋于一致,大气边界层稳定结构中存在强的大气垂直混合作用;在霾消散阶段,较高处的气溶胶粒子浓度最先下降,且下降幅度最大,表明对流层自由大气作用对霾污染消散具有影响。大气边界层风速的增大加剧了大气传输扩散。温度与大气颗粒物浓度在近地层呈负相关关系,在100m高度以上呈正相关关系。大气边界层低层偏冷,高层偏暖的稳定大气热力层结减弱了大气污染物的垂直扩散。相对湿度的增加有利于气溶胶粒子的吸湿增长和液相化学反应,加剧了霾污染。     

大气气溶胶密度观测研究进展

大气气溶胶的气候效应、环境效应、健康效应均与其物理化学性质密切相关,其中,密度是大气气溶胶重要的物理性质之一。密度影响着粒子的输送过程和在人体肺部的沉积过程。密度可以分别将电迁移率粒径和空气动力学粒径,数浓度和质量浓度联系起来。密度的变化可为气溶胶的形成和老化过程提供信息,细粒子分粒径的密度还可为大气过程和化学组分的演化提供参考依据。因此,研究大气气溶胶密度对了解气溶胶化学组分,评估气溶胶形成过程以及探究气溶胶在人体内的沉积效率具有重要的意义。由于国内在该领域研究总体较少,对大气气溶胶密度的定义、研究方法、国内外研究进展以及影响因素和变化特征等进行较为系统的总结,对未来开展大气气溶胶密度的观测和研究十分必要。     

沙尘天气对大气生物气溶胶中微生物浓度、特性和分布的影响

生物气溶胶对全球气候、空气质量、大气过程和人体健康均具有重要影响。每年爆发的沙尘事件,使得生物气溶胶可借助沙尘进行长距离输运,从而影响到下风向地区生物气溶胶的浓度和性质。综述了沙尘天气下生物气溶胶中微生物的浓度、特性和分布特征的研究现状。已有研究显示,沙尘发生时,生物气溶胶中不同类别微生物的组成比例会有显著变化,细菌和真菌相对贡献随之改变。可培养细菌、真菌和总微生物浓度,均在沙尘天气下显著增加,但不同地区不同种类微生物在沙尘天气下的增加幅度相差很大。生物气溶胶中微生物主要分布于粗粒子中,其粒径分布受到沙尘天气的较大影响,而且不同种类微生物粒径分布的变化并不相同。沙尘发生时,生物气溶胶中的微生物群落结构与优势微生物也会发生明显改变。沙尘天气对生物气溶胶浓度、粒径分布、群落结构和活性的影响程度和影响机制,还需要进一步深入研究。     

东亚季风区近地面大气气溶胶中OCPs和PCBs纬度分布：以7Be为参照系

连续一年在北京、青岛、广州以每周3d的时间尺度同步采集近地面大气中气溶胶中7Be的测定数据以及在春、秋季节变换时期我国5个不同纬度城市大气气溶胶中7Be和典型持久性有机污染物（有机氯农药和多氯联苯1的同步观测数据,并对文献上发表的我国其他城市近地面大气中气溶胶中’Be年平均值数据进行了分析。通过对以上数据资料的总结和分析,观察到在东亚季风区近地表大气气溶胶中7Be浓度的年平均值呈现正态分布模式,并且在中纬度北纬40°N附近达到极大值。大气气溶胶中7Be在春、秋季节变换时期我国不同纬度城市的瞬时纬度分布仍呈现正态分布模式,但以30°N为最大值。在秋季大气颗粒相中HCHs和PCBs浓度最大值出现在30°N。气相中PCB-28所占百分比随纬度增高而增大,而颗粒相中PCB-28的纬度变化不大。蒸汽压较低的PCB-180在气相中的浓度基本上不随纬度变化,而颗粒相中PCB-180则基本上集中在纬度36。N左右,表明在东亚季风区大气中挥发性较低的POPs化合物具有某种纬度聚焦作用。以宇宙射线成因核素7Be作为大气环流的参照系,可以得出东亚季风区大气环流可影响持久性有机污染物纬度分布的结论。     

大气气溶胶地球化学研究进展

大气气溶胶地球化学研究进展刘广深，洪业汤（中国科学院地球化学研究所，贵阳５５０００２）关键词大气，气溶胶，生物地球化学循环天然和人为的颗粒物发生过程使低层大气尤其是对流层，成为大气气溶胶的圈层。大气气溶胶在地球表面无时无处不在，对人类生活和自然过程有...     

太湖大气气溶胶中硫稳定同位素组成分析

用 MAT-253同位素质谱仪对太湖大气气溶胶中的硫稳定同位素组成特征进行了分析.结果显示,太湖大气气溶胶中δ34S 数值变化范围为4.46‰~9.87‰,表明该地区大气气溶胶的主要硫源与当地燃煤排放直接相关.Δ33S 绝对值普遍大于0.1‰,说明太湖大气气溶胶中存在显著的硫稳定同位素非质量分馏效应;基于正Δ33S 和负Δ36S 的关联,揭示太湖气溶胶中硫稳定同位素的分馏异常主要与平流层 SO2发生的光化学反应有关,该科学问题迫切需要做进一步系统深入的研究.     

Atmospheric trace metals and sulfate in the Greenland Ice Sheet

Chemical analyses of surface snow and dated deep ice core samples from central Greenland suggest that Zn, Pb and sulfate are presently being deposited there at two to three times the natural rates. No recent increases in Cd or V concentrations were observed. Pre-1900 ice shows no measurable effect of the activities of man and represents a good natural aerosol baseline. High enrichment factors relative to average crustal material were observed for Zn, Pb, Cd and sulfate in all samples indicating a natural source other than continental dust is responsible. A high temperature process or vapor phase origin for these enriched elements, possibly volcanism, seems likely.     

Characteristics and Possible Source of a 1479 A.D. Volcanic Ash Layer in a Greenland Ice Core

A microparticle concentration peak in a GISP2 ice core contains volcanic glass shards of rhyolitic composition that correspond in age to the 1479-1480 A.D. Mt. St. Helens Wn eruption. These glass shards are compositionally similar to the Wn tephra and constitute 83% of the total particle population. The shards are very coarse-grained (up to 40 μm diameter), suggesting rapid transport from their source to Greenland. A major sulfate peak in the ice occurs approximately 4 months after deposition of the glass shards. This difference in depositional timing suggests primarily tropospheric transport of the ash and stratospheric transport of the sulfate aerosol. Large-scale climatic perturbations following this eruption were evidently negligible. Glaciochemical seasonal indicators suggest a late-fall to early-winter 1479 A.D. eruption.     

Volatile properties of atmospheric aerosols during nucleation events at Pune,India

Continuous measurements of aerosol size distributions in the mid-point diameter range 20.5–500 nm were made from October 2005 to March 2006 at Pune (18°32′N, 73°51′E), India using Scanning Mobility Particle Sizer (SMPS). Volatilities of atmospheric aerosols were also measured at 40°, 125°, 175°, 300° and 350°C temperatures with Thermodenuder–SMPS coupled system to determine aerosol volatile fractions. Aerosols in nucleated, CCN and accumulated modes are characterized from the measured percentage of particles volatized at 40°, 125°, 175°, 300° and 350°C temperatures. Averaged monthly aerosol concentration is at its maximum in November and gradually decreases to its minimum at the end of March. The diurnal variations of aerosol concentrations gradually decrease in the night and in early morning hours (0400–0800 hr). However, concentration attains minimum in its variations in the noon (1400–1600 hr) due to higher ventilation factor (product of mixing height and wind speed). The half an hour averaged diurnal variation of aerosol number concentration shows about 5 to 10-fold increase despite the ventilation factor at higher side before 1200 hr. This sudden increase in aerosol concentrations is linked with prevailing conditions for nucleation bursts. The measurement of volatile fraction of ambient aerosols reveals that there are large number of highly volatile particles in the Aitken mode in the morning hours and these volatile fractions of aerosols at temperatures <150°C are of ammonium chloride and ammonium sulfate, acetic and formic acids.     

硫酸（亚硫酸）盐渍土单次盐胀和冻胀发育规律研究

对盐胀和冻胀规律的研究有助于深入认识硫酸（亚硫酸）盐渍土的工程性质。通过对天山北麓水磨河流域细土平原区硫酸（亚硫酸）盐渍土盐胀和冻胀试验研究发现：（1）随着温度的降低,试样盐胀和冻胀率逐渐增大。试样冻结前土体产生的膨胀是盐胀,试样冻结后产生的膨胀是盐胀和冻胀,当土体达到-15℃以后,土体盐胀和冻胀趋于稳定。（2）硫酸钠含量不变的情况下,随着含水量的增大,其起胀温度降低。土体起胀温度取决于土体中硫酸钠析水结晶温度、硫酸钠结晶含量的多少、土体结构、内摩阻力、粘聚力、土颗粒间的引力、土体孔隙间和孔隙接触间吸收结晶硫酸钠的程度。（3）硫酸钠含量增加,其单次盐胀和冻胀率变化区间增大。     

A New Single-Filter Method for Analyzing Coastal Aerosol Production and Links to Meteorology

Aerosols are known to influence the climate system in a range of ways; they affect radiation budgets, cloud formation and circulation patterns, and contribute to local biogeochemical cycling and ecology. Despite this recognized role for marine aerosol, however, recent research has emphasized the impact of global climate change on coastal environments rather than the other way around. This occurs in part because most methods for sampling marine aerosol are expensive and studies tend to occur only on specialized marine stations and ocean-crossing research vessels. This project tests a new method for aerosol sampling, specifically designed for use in local studies of coastal environments and costing little to set up. It also reports the results of a pilot study in Alderney (Channel Islands) where changes in both aerosol abundance and aerosol composition, including fractionation effects, were observed using the new method and linked to local meteorological conditions.     

Physical properties of aerosols at Maitri,Antarctica

Measurements of the submicron aerosol size distribution made at the Indian Antarctic station, Maitri (70‡45′S, 11‡44′E) from January 10th to February 24th, 1997, are reported. Total aerosol concentrations normally range from 800 to 1200 particles cm⁻³ which are typical values for the coastal stations at Antarctica in summer. Aerosol size distributions are generally trimodal and open-ended with a peak between 75 and 133 nm and two minima at 42 and 420 nm. Size distributions remain almost similar for several hours or even days in absence of any meteorological disturbance. Total aerosol concentration increases by approximately an order of magnitude whenever a low pressure system passes over the station. Based on the evolution of aerosol size-distributions during such aerosol enhancement periods, three types of cases have been identified. The nucleation mode in all three cases has been suggested to result from the photochemical conversion of the DMS emissions transported either by the marine air or by the air from the ice-melt regions around Maitri. Subsidence of midtropospheric air during the weakening of radiative inversion is suggested as a possible source of the nucleation mode particles in the third case. Growth of the nucleation mode particles by condensation, coagulation and/or by cloud processes has been suggested to be responsible for other modes in size distributions.     

小型氡室氡浓度准确性影响因素的探讨

小型氡室是一种综合测氡仪器的标定装置,适合目前各种测氡仪器的标定。湿度、温度、闪烁探测器的漏计现象等因素影响氡室内氡浓度。湿度影响着气溶胶的密度,湿度越大,气溶胶的密度也越大,导致探测器探测的计数也变大;温度增加,分子的扩散系数随着增加,使镭源释放的氡量增加,导致氡浓度变大;闪烁体的发光衰减时间较长,测量大活度样品时,会出现漏计现象。对应不同的影响因素采取了相应的修正措施。     

硫酸钠盐渍土击实特性与压实度评价试验研究

合理的压实度对减小硫酸盐渍土地基的盐胀和溶陷病害具有重要意义。为探讨硫酸盐渍土的击实特性、击实后的微结构特征以及合理的压实度评价方法,对不同试样制备条件下的硫酸盐渍土进行了击实试验和电镜扫描。结果表明,硫酸盐渍土的击实特性和击实后的微结构特征与土中硫酸钠的状态密切相关：硫酸钠溶液具有润滑性,其含量的增加能显著提高硫酸盐渍土的击实性能,击实后,试样的土团粒主要呈表面光滑的薄层状,土体为流纹状镶嵌结构;而十水硫酸钠具有支架作用,其含量的增加使硫酸盐渍土的击实性能大幅降低,击实后,试样的土团粒呈浑圆状、粒径很小,土体为网状架空结构。根据这一新认识,进一步分析了试样制备方法和闷料时间对硫酸盐渍土压实度的影响,并给出了相应的压实度评价建议。该研究成果可为硫酸盐渍土压实度的合理评价提供理论依据,对硫酸盐渍土地基的辗压施工工艺具有参考价值。     

The Tambora eruption in 1815 provides a test on possible global climatic and chemical perturbations in the past

A coupled one-dimensional radiative-convective-photochemical diffusion model, which takes into account the influence of ocean inertia on global radiative perturbations is used to investigate the possible climatic and other atmospheric effects of a major volcanic eruption, thought to be similar in magnitude to that of the Tambora eruption, Indonesia, which took place in 1815. A volcanic cloud was introduced in the model stratosphere between 20–25 km and the global average peak aerosol optical thickness was assumed to be 0.25. Both the aerosol optical thickness and aerosol composition, which determine the optical properties, were allowed to vary in the model atmosphere during the life cycle of the volcanic cloud. The results indicate that the global average surface temperature decreases steadily from the date of eruption (7–12 April 1815) with maximum cooling of 1° K occurring in the spring of 1816. The calculations also show significant warming of the stratosphere, with temperature increasing up to 15° K at 25 km in less than six months after the date of eruption. The important effects of the Tambora eruption on stratospheric ozone and UV-B radiation at the surface are also mentioned.     

Ice-core records of global climate and environment changes

Precipitation accumulating on the Greenland and Antarctic ice sheets records several key parameters (temperature, accumulation, composition of atmospheric gases and aerosols) of primary interest for documenting the past global environment over recent climatic cycles and the chemistry of the preindustrial atmosphere. Several deep ice cores from Antarctica and Greenland have been studied over the last fifteen years. In both hemispheres, temperature records (based on stable isotope measurements in water) show the succession of glacial and interglacial periods. However, detailed features of the climatic stages are not identical in Antarctica and in Greenland. A tight link between global climate and greenhouse gas concentrations was discovered, CO₂ and CH₄ concentrations being lower in glacial conditions by about 80 and 0.3 ppmv, respectively, with respect to their pre-industrial levels of 280 and 0.65 ppmv. Coldest stages are also characterized by higher sea-salt and crustal aerosol concentrations. In Greenland, contrary to Antarctica, ice-age ice is alkaline. Gas-derived aerosol (in particular, sulfate) concentrations are generally higher for glacial periods, but not similar in both the hemispheres. Marine and continental biomass-related species are significant in Antarctica and Greenland ice, respectively. Finally, the growing impact of anthropogenic activities on the atmospheric composition is well recorded in both polar regions for long-lived compounds (in particular greenhouse gases), but mostly in Greenland for short-lived pollutants.