广州市空气可吸入性颗粒物的污染水平

报告了中美合作“广州市大气污染对儿童肺功能影响研究”课题可吸入性颗粒物的两年监测结果。用安德森双道采样器、Ｔｅｆｌｏｎ膜采集细颗粒物（＜２５μｍ，ＰＭ２５）和粗颗粒物（２５≤＜１０μｍ，ＰＭ２５１０），两者之和为ＰＭ１０，每季度采１５天，每天采一个２４小时样品。结果表明，广州市城区大气可吸入性颗粒物的污染相当严重，尤其是细颗粒物（ＰＭ２５）的污染，应引起公众和政府有关部门的重视。     

Forty years of atmospheric radiocarbon monitoring around Bohunice nuclear power plant, Slovakia

Radiocarbon variations in the atmospheric CO(2) with attenuating amplitudes and decreasing mean values with typical maxima in summer and minima in winter have been observed since 1967 in two localities of Slovakia, in Bratislava and Zlkovce, situated about 60 km NE from Bratislava, only 5 km from the Bohunice Nuclear Power Plant (NPP). The (14)C record in Bratislava has been influenced mainly by fossil CO(2) emissions, in contrast to the Zlkovce record which has been more variable, as it has clearly been affected by operation of the Bohunice NPP. However, during specific meteorological conditions with NE transport of air masses to Bratislava, the effect of the Bohunice NPP has been visible in Bratislava as well. Maximum (14)C concentrations (up to 120% above a natural background) were observed around A1 NPP which used CO(2) with admixture of air as a cooling agent. The (14)C concentrations around four pressurized light water reactors were up to 30% above the background. The Delta(14)C values in the heavily polluted atmosphere of Bratislava were up to 10% and at Zlkovce up to 5% lower than the European clean air represented by the Jungfraujoch Delta(14)C data. Later the Delta(14)C values were similar at both sites, and from 2003 they were close to the European clean air levels. The observed Delta(14)C behaviour in the atmosphere provides a unique evidence of decreased fossil fuel CO(2) emissions in the region, as well as the long-term effect of the Bohunice NPP on the Bratislava and Zlkovce stations. The estimated annual radiation doses to the local public due to digestion of radiocarbon contaminated food have been estimated to be around 3 microSv.     

基于元胞自动机的弱视条件下群体疏散的仿真研究

根据人在弱视情况下的行为特征,建立基于元胞自动机的逃生模型,对弱视情况下的人群疏散进行了模拟。模拟过程中考虑了人的学习能力及人与人之间的相互作用等因素,模型加入吸引子使模拟人的疏散行为更为灵活。基于人能通过熟悉周围环境作出合理判断的学习能力,引入了"积累步长"的概念,使人的沟通判断能力(走过的路径、边界和出口位置通过交流能够获取)在模型中得到体现。获取足够信息的人可以避免多余的寻找,降低了逃生时间,体现了"人多力量大"的互助行为。通过大量的模拟实验,并讨论不同的环境条件对人群疏散的影响。     

Comparison of atmosphere/aquatic environment concentration ratio of volatile chlorinated hydrocarbons between temperate regions and Antarctica

For the purpose of understanding the transport and deposition mechanisms and the air–water distribution of some volatile chlorinated hydrocarbons (VCHCs), their atmosphere/aquatic environment concentration ratio was evaluated. In addition, for the purpose of differentiating VCHC behaviour in a temperate climate from its behaviour in a polar climate, the atmosphere/aquatic environment concentration ratio evaluated in matrices from temperate zones was compared with the concentration ratio evaluated in Antarctic matrices.In order to perform air samplings also at rigid Antarctic temperatures, the sampling apparatus, consisting of a diaphragm pump and canisters, was suitably modified.Chloroform, 1,1,1-trichloroethane, tetrachloromethane, 1,1,2-trichloroethylene and tetrachloroethylene were measured in air, water and snow using specific techniques composed of a purpose-made cryofocusing-trap-injector (for air samples) and a modified purge-and-trap injector (for aqueous samples) coupled to a gas chromatograph with mass spectrometric detection operating in selected ion monitoring mode. The VCHCs were retrieved in all the investigated matrices, both Italian and Antarctic, with concentrations varying from tens to thousands of ng m⁻³ in air and from digits to hundreds of ng kg⁻¹ in water and snow.The atmosphere/aquatic environment concentration ratios were always found to be lower than 1. In particular, the Italian air/water concentration ratios were smaller than the Antarctic ones, by reason of the higher atmospheric photochemical activity in temperate zones. On the other hand, the Antarctic air/snow concentration ratios proved to be largely in favour of snow with respect to the Italian ratios, thus corroborating the hypothesis of a more efficient VCHC deposition mechanism and accumulation on Antarctic snow.     

灰霾天气与大气颗粒物的相关性研究综述

随着城市化进程的迅速发展,城市大气污染加剧,灰霾天气也随之增多。综述了灰霾天气期间大气颗粒物在时空分布和污染水平2方面的污染特征,分析了大气颗粒物与能见度相关性,介绍了国内外对灰霾天气期间大气污染物的组成及源解析方面的研究进展,并提出了今后灰霾天气的研究方向。     

Characteristics of lead geochemistry and the mobility of Pb isotopes in the system of pedogenic rock–pedosphere–irrigated riverwater–cereal–atmosphere from the Yangtze River delta region,China

Knowledge of the characteristics of Pb and its isotopic transfer in different compartments is scant, especially for the mobility of Pb isotopes in the geochemical cycle. The present study characterizes differential Pb transport mechanism and the mobility of Pb isotopes in the pedogenic parent rock–pedosphere–irrigated riverwater–cereal–atmosphere system in the Yangtze River delta region, by determining Pb concentration and Pb isotopic ratios of pedogenic parent rocks, fluvial suspended particle matter, tillage soils, soil profiles, irrigated riverwater, fertilizer, Pb ore, cereal roots and grains. The results show that Pb isotopes in the geochemical cycle generally follow the equation of ²⁰⁸Pb/²⁰⁶Pb = −1.157 × ²⁰⁶Pb/²⁰⁷Pb + 3.46 (r² = 0.941). However, Pb isotopes have different mobility in different environmental matrixes. Whereas in the pedosphere, the heavier Pb (²⁰⁸Pb) usually shows stronger mobility relative to the lighter Pb, and is more likely to transfer into soil exchangeable Pb fraction and carbonates phase. The lighter Pb shows stronger transfer ability from soil to cereal grain via root compared to the heavier Pb. However, the cereal grains have lower ²⁰⁶Pb/²⁰⁷Pb and higher ²⁰⁸Pb/²⁰⁶Pb ratios than root and tillage soil, similar to the airborne Pb and anthropogenic Pb, implying that a considerable amount of Pb in cereal grains comes from the atmosphere. The estimate model shows that 16.7–52.6% (average: 33.5%) of Pb in rice grain is the airborne Pb.     

太湖氮磷大气干湿沉降时空特征

为了探索太湖氮磷营养盐干湿沉降特征及对太湖营养盐输入的贡献，于2011年不同季节采集太湖不同位点的大气干湿沉降样品，分析干湿沉降中氮（N）和磷（P）的形态和沉降量。研究结果表明，输入太湖的磷以干沉降为主，而氮以湿沉降为主。在太湖干沉降中总无机氮（TIN）占总氮（TN）的77.1%，溶解性磷（DIP）占总磷（TP）的77.9%。干沉降中TIN主要以NH+4-N为主。西太湖是TN与TP通过大气干湿沉降输入太湖的最高湖区。太湖全年大气TN沉降总量为20 978 t，TP沉降总量为1 268 t，因此，氮磷大气干湿沉降是太湖营养盐输入的重要来源之一。     

雾霾时车辆尾气排放对驾驶员能见度的影响

针对北京道路车辆尾气排放对雾霾时驾驶员道路能见度的影响问题,建立了雾霾时车辆尾气排放与驾驶员道路能见度关系模型。该模型以车辆为单元建立车辆尾气排放元胞,考虑了车辆尾气排放后的污染物物理和化学变化,并以车道中的尾气排放位置截面及截面单元、交叉口处的尾气排放位置区间为模型单元。为验证该模型,于2016年10月-2017年2月和2017年10月-2018年2月,在北京地区部分路网检测了驾驶员道路能见度等数据,并统计了各时段驾驶员道路能见度的分布情况。对建立的关系模型进行仿真,结果表明,该关系模型的仿真结果与实际检测数据的误差占比平均值小于4. 98%,验证了该关系模型用于描述北京市道路车辆尾气排放对雾霾时驾驶员道路能见度影响的有效性。     

烟塔排烟电厂大气影响预测分析

在系统分析我国烟塔排烟电厂大气影响评价及其相关研究成果的基础上，指出应关注的几个问题，并结合烟塔排烟电厂的负荷变化特点提出了解决问题的基本思路及需要重点研究的专题。     

深圳市大气能见度特征分析及其与主要污染物因子相关性分析

近些年,随着深圳市大气污染防治举措的加强,空气质量不断趋好。文章汇总了深圳市2006～2009年大气能见度特征数据,分析了深圳市能见度的年度、季度和月度变化,发现近些年深圳市大气能见度具有向好的发展趋势。探讨了大气能见度与空气主要污染物PM10、NO2、SO2的相关关系,计算了PEARSON相关系数和偏相关系数,发现PM10浓度与能见度具有显著相关性。在此基础上总结了各个主要污染物与能见度的回归曲线。利用多元线性回归法建立了大气能见度与空气主要污染物PM10、NO2、SO2之间的回归方程。