大气气溶胶中痕量金属元素的研究进展

综述了近年来国内外学者对大气气溶胶中痕量金属元素的研究进展,介绍了痕量金属元素的地球化学行为,以及大气气溶胶中痕量金属的源解析方法、在环境中的循环与污染、生物有效性及对人体的健康效应。建议研发更可靠的分析方法或在线检测仪器,避免采样和样品前处理过程中痕量金属的污染和损失;建立监测网络,形成区域性的大气监测模式,更全面地分析污染来源;与监测超级站建设、空气污染流行病学设计和毒性机制研究相结合,建立更加完善的研究体系。     

灰霾天气期间南京气溶胶的化学组成及光学特性研究

利用2013年6月—12月灰霾天气期间南京城郊气溶胶采样结果,研究气溶胶中水溶性离子的特征和相关性;结合同期城区的大气成分逐时观测资料,分析黑碳的日变化及其与气态污染物的关系;运用光学参量计算模型(OPAC)和辐射传输模型(TUV)研究气溶胶的光学特性及辐射强迫。结果表明:发生灰霾天气时南京城郊主要大气污染物是细颗粒,其中SO2-4与NO-3是最主要的水溶性无机盐离子,NO-3/SO2-4质量比较高,呈现硫酸盐和硝酸盐混合型污染特征。黑碳浓度具有明显的日变化特征,呈双峰型结构。灰霾期间硫酸盐气溶胶在大气层顶和地面造成的平均辐射强迫分别为-10.6 W/m2和-10.8 W/m2,黑碳气溶胶在正午大气层顶和地面造成的平均辐射强迫分别为9.12 W/m2和-29.77 W/m2。     

太湖上空大气气溶胶光学厚度及其特征分析

基于高精度的太阳光度计(CE-318)得到太湖上空气溶胶长期观测数据,获得了太湖上空从2005年9月～2010年10月的气溶胶光学厚度(AOT)以及相应的ngstrm参数α.5 a的观测资料表明,太湖上空AOT的高值区出现在夏季的6～7月,低值区出现在秋冬季节的10月～次年1月;α的低值区和高值区分别出现在春季的3～4月和秋季的9～11月,AOT及对应的α的变化主要与该地区的天气形势有关.从频率分布来看,AOT(500 nm)只有一个峰值,最高频率值为0.4～0.6,约占总样本的26%,年均值为0.80.按照平均AOT(500 nm)计算,气溶胶造成的太阳直射辐射的透过率衰减至少为50%,致使太湖地区的大气较为混浊,形成严重的雾霾天气;ngstrm波长指数α有2个峰值,最高频率区间为1.1～1.3和1.3～1.5,分别占总样本的30%,年平均值为1.17.结果还表明AOT(500 nm)和α的日均值变化范围均较大,表明太湖上空有不同类型的气溶胶粒子共存;当α增大时,AOT(500 nm)的均值呈递减趋势.总体结果分析表明,太湖上空的AOT值随时间变化较大,属于城市-工业型气溶胶类型.     

杭州市大气气溶胶光学特性研究

利用太阳分光光度计（CE-318）对杭州市地面的气溶胶光学特性进行观测,并对卫星反演的中分辨率成像光谱仪（Moderate Resolution Imaging Spectroradiometer,MODIS）气溶胶产品进行验证.结果表明,MODIS气溶胶产品在杭州地区的精度较高,3个站点全部数据回归曲线的斜率和截距分...     

北京大气气溶胶小颗粒的测量与解析

本项研究是对空气动力学直径小于2．5μm的气溶胶粒子进行测量分析。为此在北京设立2个采样点,分别从1989年4月30日到1989年5月16日和从1989年5月20日到1990年5月14日进行采样。样品用热光碳分析仪分析其中的有机碳(OC)和元素碳(EC),用X射线荧光光谱仪分析其中的28种元素,用离子色谱分析其中的,表征了北京大气中小颗粒气溶胶的化学特征。对所得的数据用化学质量平衡模式(CMB)法进行处理,得出了各种污染源对气溶胶小颗粒的贡献率。      

南极大气气溶胶中铅同位素比值的研究

通过对电感耦合等离子体质谱(ICP-MS)的工作条件和参数进行优化,建立了ICP-MS测定铅同位素比值的精确方法,测量了2007—2009年南极中山站采集到的气溶胶样品中208Pb/206Pb、207Pb/206Pb和206Pb/207Pb的比值。结果表明,南极大气气溶胶中铅同位素比值在逐年缓慢地发生线性变化,线性相关系数为0.996 2;气溶胶铅同位素示踪揭示南极附近国家(除南非)释放的铅可能成为南极大气中铅的重要来源。     

MODIS遥感气溶胶光学厚度产品在地面能见距中的应用

利用气象站点能见距的历史资料和NASA的MODIS卫星遥感手段获取10km*10km分辨率的气溶胶光学厚度资料,建立二者之间的季节平均关系,得到了上海地区季节变化的气溶胶标高,并利用标高数据和气溶胶光学厚度的季节分布,反演出上海地区季节变化的区域能见距分布,研究近地层大气气溶胶与地面能见距的关系,分析上海市能见度时空分布特征,结果显示:上海城区在冬春季平均能见距较差,市区中心能见距在10km以下;低能见距中心分布明显,且主要分布在杨浦、桃浦、吴淞等工业区范围.     

Variations and drivers of aerosol vertical characterization after clean air policy in China based on 7-years consecutive observations

Understanding the aerosol vertical characterization is of great importance to both climate and atmospheric environment. This study investigated the variations of aerosol profiles over eight regions of interest in China after clean air policy (2013-2019) and discussed the drivers of the vertical aerosol structure, using observations from active satellite measurements (CALIPSO). From the annual variation, the amplitude of extinction coefficient profiles showed a decreasing trend with fluctuations, and the maximum was 0.21 km⁻¹ in Beijing-Tianjin-Hebei (JJJ). For regions suffered from air pollution, the variation was greatest below 0.45 km, while it was between 1-1.5 km for Sichuan Basin. The correlation coefficient between the relative humidity (RH) and the extinction coefficient indicated that the increase of RH inhibited the decrease of the extinction coefficient in the Yangtze River Delta. In most regions, the main aerosol subtypes were polluted dust and polluted continental, but they were coarser in JJJ and North West. The frequency of concurrency of dust and polluted dust aerosols decreased in JJJ, but polluted continental aerosols occurred more frequently. Further, the aerosol extinction coefficient profiles under different pollution conditions showed that it changed most during heavy pollution periods in JJJ, especially in 2017, with a significant aerosol loading between ∼700 and 1200 m. The atmospheric reanalysis data revealed that the weak convergence at low level and the divergence at high level supported the upward transport of aerosols in 2017. Overall, the differences in divergence allocation, RH, and wind filed were the main meteorological drivers.     

西南地区大气中硫的化学特性及其对降雨的贡献率

1987-1989年春秋季在西南重庆、贵阳、成都和广元等地区采集大气颗粒物和雨水样品，测定了其中S和SO4^2-。探讨了颗粒物中S在粗细粒中的分布及水溶性S的百分比，估算了大气中S在气相(SO2)、液相(H2SO4)及固相(SO4^2-)中的分配比例，得知颗粒物中S对降雨的贡献率为18～50％。     

Atmospheric mineral particles collected at Qira in the Taklamakan Desert, China

Aerosol particles were collected in the situation of the widespread dust suspension on 21 February 1991 at Qira in the southern edge of the Taklamakan Desert, western China. The collected particles were examined by a transmission electron microscope equipped with an energy-dispersive X-ray (EDX) analyzer in order to obtain the size and elemental composition of individual mineral particles.On the basis of EDX analyses for 386 particles, mineral particles were present in high number fractions (>99%) of particles in the radius range of 0.1–4 μm. Particles mainly composed of silicates comprised 76% of mineral particles. “Ca-rich” particles were detected in 7% of all the particles. Ca in the particles would be present not only as CaCO₃ but also as an internal mixture of CaCO₃ and CaSO₄. Particles containing halite (NaCl) were detected in number proportions of about 10% and were mainly present in the radius range of 0.5 μm. Some halite particles would be modified by chemical reactions with sulfuric acid.