广东省清远市PM2.5污染天气分型及污染潜在源区分析

利用2016—2021年清远市逐时空气质量监测数据和相关气象资料,基于统计分析、主观天气分型方法和后向轨迹模式（HYSPLIT）,归纳总结粤北代表城市清远市在不同细颗粒物（PM_2.5 ）污染天气分型下的气象要素特征及污染潜在源区特征,为大气污染精细化防控提供有效参考。结果表明：在日均风速＜2m/s、日均相对湿度为75%～90%、日均气温为18～22℃时的无降水或微量降水天气下,清远市易出现PM_2.5 污染。变性高压脊型、脊后槽前型、冷锋前型、弱冷高压脊型、高压底后部型、台风外围型是造成清远市PM_2.5 污染的典型天气型,其中PM_2.5 重度污染均出现在秋、冬季弱冷高压脊型控制下;变性高压脊型下出现PM_2.5 轻度和中度污染的频率最高;脊后槽前型是清远市春季PM_2.5 污染的主要天气型;冷锋前型、高压底后部型和台风外围型下的PM_2.5 污染程度较轻。加剧清远市PM_2.5 污染的主要气流轨迹为弱偏南气流和南北气流辐合,当弱偏南气流控制时,污染潜在源区主要位于清远市辖区及广州、佛山、东莞、江门等珠三角城市;当南北气流辐合时,潜在源区主要位于清远市南部、韶关及珠三角,南岭山脉阻挡作用削弱了偏北方向长距离输送的PM_2.5 污染。     

Characterization, reactivity, source apportionment, and potential source areas of ambient volatile organic compounds in a typical tropical city

Based on one-year observation, the concentration, sources, and potential source areas of volatile organic compounds (VOCs) were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou, China. The results showed that the annual average concentration of total VOCs (TVOCs) was 11.4 ppbV, and the composition was dominated by alkanes (8.2 ppbV, 71.4%) and alkenes (1.3 ppbV, 20.5%). The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening. The greatest contribution to ozone formation potential (OFP) was made by alkenes (51.6%), followed by alkanes (27.2%). The concentrations of VOCs and nitrogen dioxide (NO₂) in spring and summer were low, and it was difficult to generate high ozone (O₃) concentrations through photochemical reactions. The significant increase in O₃ concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast. Traffic sources (40.1%), industrial sources (19.4%), combustion sources (18.6%), solvent usage sources (15.5%) and plant sources (6.4%) were identified as major sources of VOCs through the positive matrix factorization (PMF) model. The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models. Overall, the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport, and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou, thereby reducing the generation of O₃.     

京津冀地区典型城市秋冬季PM2.5输送特征研究

运用潜在源贡献分析（PSCF）方法,识别了2018年秋冬季京津冀地区典型城市北京,唐山和石家庄PM_2.5的潜在污染源区;基于气象-空气质量模式（WRF-CAMx）和传输通量计算方法定量评估了与其周边省市之间PM_2.5的传输贡献,识别了三个典型城市PM_2.5的传输路径,揭示了PM_2.5传输净通量的垂直分布特征.结果表明,三个城市秋冬季PSCF高值主要集中在河北南部,河南东北部和山西中东部地区;秋冬季PM_2.5均以本地贡献影响为主（51.78%~68.40%）,外来贡献为辅（31.60%~48.22%）,不同季节贡献率有所波动.整个观测期间,近地面主要表现为毗邻城市向北京和石家庄输送PM_2.5,而唐山主要表现为向外输送PM_2.5,净通量最大值出现在海拔0~50m,其净通量为-99.47t/d.同时鉴别出了一条主要的传输路径,即西南-东北方向.     

水源地周边土壤重金属分布特征及潜在风险-以深圳市为例

以深圳市水源地周边三种不同类型土壤(赤红壤､红壤､水稻田土)为研究对象,选择具有较高环境含量且毒性较强的Zn､Pb､As为目标,探究其在三种土壤剖面淋溶层､淀积层和母质层(A、B和C层)中的分布特征及赋存形态,同时分析重金属含量､赋存形态与土壤理化性质的相关性,并利用潜在生态危害指数法和潜在迁移指数法从重金属全量和赋存形态两个角度对土壤重金属的生态风险水平进行评估.结果表明:土壤重金属Zn､Pb､As在三类土壤各层中含量较高,但均低于当地土壤环境质量背景值,重金属含量受当地土壤成岩母质影响较大.形态分析表明三种重金属在三类土壤中均以残渣态为主,但红壤中可还原态Pb含量较高,在低pH时易转化为弱酸可溶态,而后释放并迁移.相关性分析表明Zn､Pb的全量与有机质含量呈极显著正相关,可还原态Zn与pH呈显著正相关,Pb和As的弱酸可溶态与可还原态显著正相关,黏粒和粉粒含量对Pb和As的形态分布造成不同程度的影响.三种重金属潜在生态危害级别均为轻微,对水源地安全潜在生态风险影响较小;重金属迁移能力大小在不同土类中依次为红壤土>赤红壤>水稻田土,元素本身迁移能力强弱依次为Zn>As>Pb;赤红壤和水稻田土A层Zn迁移能力最强,B层As最强,C层Zn､Pb､As均较弱;红壤中A层迁移能力Zn最强,B层Zn､Pb､As均较强,C层Zn､Pb､As均较弱.     

Chemical characteristics of trace metals in PM10 and their concentrated weighted trajectory analysis at Central Delhi, India

Trace metals associated with PM₁₀ aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested 5 PCs, which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin, while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu, Pb, and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu, Cd, Zn, and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana regions. Furthermore, concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.     

云南酸控区土壤重金属释放特征及潜在风险

研究了云南省酸雨控制区3种土壤重金属Pb、Zn、Cu在模拟酸雨淋溶作用下的释放特征,并进行了酸雨淋溶前后的潜在风险评价.结果表明,重金属在模拟酸雨作用下很快溶出,约30 h后趋于平稳,3种重金属Pb、Zn、Cu最大累计释放量分别为102.32、52.19和70.54 mg/kg.不同pH下重金属的溶出趋势基本相同,重金...     

海南岛潜在震源区的研究

本文应用人工神经网络原理,以地震构造和地震活动性为主要特征,对我国海南岛进行了潜在震源区的定量划分。这种划分既反映了当前人们对地震发生规律的认识水平,又为城建部门按照工程重要性和使用年限选取相应的抗震设计参数提供了依据。     

中国光伏电池组件的生命周期评价

在收集2009年我国光伏组件生产的主流及最优技术水平数据的基础上,采用Ecoinvent数据库中辅助材料的生命周期数据,开展了我国光伏组件生命周期评价研究,计算了能量回收期和全球变暖潜值,并探讨了不同生产步骤和生产参数的影响.结果表明:太阳能级多晶硅生产和铸锭、切片工艺的技术水平对光伏产品的能量消耗和环境影响最大,我国主流技术水平情景下的产品能耗和环境影响远大于最优技术水平.对于我国光伏产业来说,要降低光伏产品的环境影响,应着重从改进多晶硅生产技术和提高硅片切割效率入手.      

HALT试验技术的研究

高加速寿命应力试验（HALT）,是一种通过施加阶梯强化应力于试品,达到快速发现产品潜在缺陷,操作设计边际及结构强度极限的试验方法,主要应用于产品研发设计阶段。由于该方法效果明显,目前已越来越多的电子电气产品制造商认可并推广使用,成为研发设计工程师提高产品可靠性的重要试验手段。本文简要介绍HALT试验的目的,并结合实际,探讨了HALT试验设备的关键性能指标。另外,基于日常实践经验,重点分析和讨论了HALT试验过程中应该关注的一些技术处置措施,从而帮助测试人员正确执行HALT。     

中国电池生产用汞量及潜在汞散失量估算

从含汞电池的生产与消费、单位电池含汞量的估算、电池生产用汞量及潜在汞散失量的估算3个方面,对1992～1999年我国电池生产用汞量和潜在汞散失量进行了分析。结果表明,1992～1999年期间我国电池生产用汞量先减后增再减,其中2个高峰分别为1992年的679.5t和1997年的974.3t;潜在汞散失量呈上升趋势,1999年达801.7t。因此,我国电池引起的汞污染问题不容忽视。