Ozone episodes during and after the 2018 Chinese National Day holidays in Guangzhou: Implications for the control of precursor VOCs

The impact of reducing industrial emissions of volatile organic compounds (VOCs) on ozone (O₃) pollution is of wide concern particularly in highly industrialized megacities. In this study, O₃, nitrogen oxides (NOx) and VOCs were measured at an urban site in the Pearl River Delta region during the 2018 Chinese National Day Holidays and two after-holiday periods (one with ozone pollution and another without). O₃ pollution occurred throughout the 7-day holidays even industrial emissions of VOCs were passively reduced due to temporary factory shutdowns, and the toluene to benzene ratios dropped from ∼10 during non-holidays to ∼5 during the holidays. Box model (AtChem2-MCM) simulations with the input of observation data revealed that O₃ formation was all VOC-limited, and alkenes had the highest relative incremental reactivity (RIR) during the holiday and non-holiday O₃ episodes while aromatics had the highest RIR during the non-pollution period. Box model also demonstrated that even aromatics decreased proportionally to levels with near-zero contributions of industrial aromatic solvents, O₃ concentrations would only decrease by less than 20% during the holiday and non-holiday O₃ episodes and ozone pollution in the periods could not be eliminated. The results imply that controlling emissions of industrial aromatic solvents might be not enough to eliminate O₃ pollution in the region, and more attention should be paid to anthropogenic reactive alkenes. Isoprene and formaldehyde were among the top 3 species by RIRs in all the three pollution and non-pollution periods, suggesting substantial contribution to O₃ formation from biogenic VOCs.     

Water incubation-induced fluctuating release of heavy metals in two smelter-contaminated soils

The soil moisture regime can affect the release of heavy metals in soil. In the previous studies, slightly polluted soils or artificially contaminated soil samples were considered to investigate the effect of soil moisture. We used highly smelter-contaminated and aged soils to study the release of typical heavy metals(Cu, Zn, Cd and Pb) induced by water incubation in batch experiments with characterization via speciation and X-ray diffraction analyses(XRD). The results show that the leachable concentrations of the heavy metals increased slightly in the first 30 days, decreased drastically between 30 and 90 days, and immobilized relatively constant thereafter. The fluctuation was ascribed to the changes of soil Eh and pH, the reductive dissolution of crystalline iron oxides, the formation of new amorphous iron oxides, the absorption of dissolved organic matter and the precipitation of metal sulfide. Speciation analysis indicated that a proportion of the soil heavy metals was transformed from an exchangeable fraction to a less labile fraction after water incubation. And the presence of a lead iron oxide phase and the peak increasing of zinc sulfide were observed via XRD analyses. Finally, water incubation restrained the release of heavy metals after 180 days of incubation, and reduced the leachability of Cu, Zn, Cd and Pb by as much as 1.61%–7.21% for soil A and 0.43%–3.36% for soil B, respectively. The study findings have implications for the formulation of risk control and management strategies for heavy metals in smelter-contaminated soils.     

京津冀及周边地区大气污染综合立体观测网的建设与应用

京津冀及周边地区大气染污综合立体观测网针对的是大气重污染发生-演变-消散全过程的核心科学问题,通过制定适用于京津冀及周边地区的大气污染综合观测技术规范,建立了区域大气污染综合立体观测网,开展了近地面及大气边界层气象和大气化学过程的同步观测,构建了监测数据综合分析及共享应用平台,实现了大气环境多源数据综合管理业务化,为大气重污染成因研究提供精准数据集,提升了京津冀秋冬季重污染成因机制研究和精细化源解析的能力,推动了京津冀及周边地区空气质量的持续改善.京津冀及周边地区大气污染综合立体观测网开展了传输通道的加密观测,增加了背景站和手工采样点观测,建立了包括黑碳、氨和重金属等多要素的关键站点,并充分利用了服务于科学研究的超级站和垂直梯度观测技术.京津冀及周边地区大气污染综合立体观测网和数据平台的建立,实现了业务部门与科研部门数据的有效融合与综合管理业务化,具有效率高、代表性好、目的性强的特点,能够很好地应对决策部门不断提高的管理需求.观测网络和平台充分吸取了国外的先进技术和观测经验,保证了观测网长期稳定运行;通过综合环境空气质量监测预警和发布平台,为环境空气质量监测和污染成因综合研究提供技术支撑,最终为实现我国空气质量的全面改善奠定了坚实的基础.      

山东省不同地形区降雨侵蚀力时空变化特征

掌握降水及降雨侵蚀力的时空分布和演变特征对于揭示区域气候变化规律,有效预防和科学评估水土流失等环境问题具有重要意义。基于34个气象站点1961—2015年的降水日值数据,采用降雨侵蚀力计算模型、Mann-Kendall检验、小波分析和Kriging空间插值等研究方法,分析研究了山东省内山地、丘陵和平原等不同地形区的降水和降雨侵蚀力时空变化特征。结果显示：近55年间,全省及各地形区的降水量和降雨侵蚀力均呈波动下降趋势,年内分配均集中在夏季,降雨侵蚀力在时间尺度上存在25年左右的变化周期。空间上,降水和降雨侵蚀力均呈现鲁中南山区＞胶东半岛丘陵区＞鲁西北平原区;分界线由东北至西南沿福山—莱阳—淄博—定陶等站呈“S”型贯穿山东省,界线东南侧降雨侵蚀力高,西北侧降雨侵蚀力较低。其原因主要是受海拔和地形的影响,东南季风携带湿润气流受胶东半岛丘陵及鲁中南山地的阻挡抬升,致使“S”型分界线东南侧迎风面降水及降雨强度相对较高;西北侧背风面形成焚风效应,降水及降雨侵蚀强度较低。该结果可为山东省水土流失空间特征分析奠定数据基础,同时为区域水土资源利用与调控及生态环境保护与改善提供决策支撑。     

武汉市无公害蔬菜生产的问题与对策

介绍了我国部分城镇在粮食作物和蔬菜产品受化学农药等有害化学物污染简况和无公害蔬菜的研究进展。调查分析了武汉市目前蔬菜生产中农药污染的现状与问题，提出了在武汉市实施无公害蔬菜生产示范工程项目的建议和对策，并进行了讨论。     

我国东部沿海地区差距状况以及经济低谷地区的崛起

我国是区域发展差异巨大的大国之一，存在着多种尺度的区域发展差异。从中小尺工区域差异的角度，分析了我国东部沿海地区内部发展差距扩大趋势有其影响，可以看出，东部沿海地区在经济快速发展的同时，也存在着经济相对落后的低谷地区。沿海经济低谷地区分布相对集中于香港－－珠江三角洲、上海－长江三角洲、京津唐－环渤海三个经济隆起带之间，处于省际交界处。按照类型可以分为黄泛平原区、丘陵山区和沿海库区。东部经济低谷地区区位条件相对比较落后，交通可达性较差，产业结构单一，城市化水平发展严重滞后，社会经济发展比较缓慢，这些不利因素制约着该地区经济和社会的发展。根据崛起机制和途径，低谷地区发展呵以分为资源转换型、非国有经济推动型和外资推动型。建议国家修筑贯穿沿海经济低谷地区的东部沿海铁路大通道，降低沿海经济低谷地区设定标准，加快农业产业化发展，对特殊贫困地区实行特殊优惠政策，从而促进东部沿海地区经济协调发展。     

长江上游攀西—六盘水地区资源开发与环境保护

长江上游攀西——六盘水地区是个资源富集的“金三角”。通过交通先行,加快资源开发,对增强21世纪经济发展后劲意义重大。但生态环境恶化,急需加强保护。     

雷州半岛与海南岛砖红壤养分比较研究

雷州半岛与海南岛砖红壤养分比较研究罗凯（广东省徐闻县农村工作委员会，徐闻５２４１００）ＣｏｍｐａｒｉｓｏｎｏｆＮｕｔｒｉｅｎｔｓＣｏｎｔｅｎｔｏｆＬａｔｏｓｏｌｓｉｎＬｅｉｚｈｏｕＰｅｎｉｎｓｕｌａａｎｄＨａｉｎａｎＩｓｌａｎｄ￥ＬｕｏＫａｉ（Ｒｕｒ...     

耕地不同产量水平的面积与分布监测法

查清中低产田的面积、分布与开发条件是制定农业综台开发规划的重要依据。采用按公里网布设的农业资源动态监测系统,开展对耕地不同产量水平的面积与分布的动态监测,其方法具有准确、简便和实用的特点。