The Urbanization Pattern of China in the 21st Century

The 21st century is referred to as a "century for cities"or "era for cities", and China has also speeded up its processof urbanization, which will bring massive influence to theeconomic development of the country and also to theworld. Joseph E. Stiglize, a winner of The Nobel Prize onEconomy, said that (the urbanization in China and thedevelopment of high technologies in the United Stateswill be two major subjects with a profound effect to thedevelopment of all mankind in the 21st century) …     

兰州市沙尘天气与痤疮门诊量的时间序列

研究沙尘天气、非沙尘天气下颗粒物（PM_2.5、PM_C、PM₁₀）对痤疮门诊量的影响,并进行性别、年龄分层研究,筛选敏感人群.收集了2013~2017年兰州市沙尘期与非沙尘期3家三甲医院痤疮门诊量资料、大气颗粒物及气象数据,采用基于泊松分布的分布滞后非线性模型（DLNM）,控制气象因素、季节性和长期趋势、星期几效应等混杂因素,分析沙尘期与非沙尘期颗粒物对痤疮门诊量的影响及滞后效应.结果表明：沙尘期时,兰州市3家三甲医院痤疮日均门诊量为26人次,范围3~54人次.非沙尘期时痤疮日均门诊量为37人次,范围1~89人次;单污染物模型显示,PM_2.5、PM_C、PM₁₀均在滞后第6d （lag6）时效应量达到最大值,其浓度每增加10μg/m³,痤疮门诊量的超额危险度（ER）及95%可信区间（95% CI）分别为1.065（95% CI：0.260~1.877）、0.355（95% CI：0.018~0.693）、0.310（95% CI：0.054~0.567）,PM_2.5对痤疮门诊量的影响最为显著;性别及年龄分层发现,性别分层中PM_2.5对女性的影响有统计学意义,其浓度每增加10μg/m³,痤疮门诊量增加1.077（95% CI：0.124~2.039）;年龄分层中,0~18岁组受PM_C、PM₁₀影响显著,19~24岁组受PM_2.5、PM₁₀影响显著,各颗粒物对25~34岁组及≥35岁组效应无统计学意义.在非沙尘期时,PM_2.5、PM_C、PM₁₀不引起痤疮门诊量增加.双/多污染物模型显示,分别调整其他污染物后,PM_2.5、PM_C、PM₁₀对痤疮门诊量的影响与单污染物模型类似,仍具有统计学意义.兰州市沙尘天气下大气颗粒物（PM_2.5、PM_C、PM₁₀）可使痤疮门诊量增加,对女性及青少年影响显著.     

建筑垃圾产量预测与时空特征研究:以南京江北新区为例

建筑垃圾的产量预测与时空特征分析是制定城市建筑垃圾资源化管理方案的重要参考依据。界定了建筑垃圾的定义与分类,提出基于情景分析的单位建筑面积建筑垃圾产量预测方法,并以南京市江北新区直管区为例,采集控制性详细规划、倾斜摄影地图、地形图、百度全景地图、年度在建施工项目与征收项目清单等基础资料,对江北新区直管区近期（2018年）与远期（2019—2030年）的拆建垃圾产量进行估算与分析;同时借助ArcGIS技术,采用核密度分析实现拆建垃圾空间分布的可视化与特征分析,为后续建筑垃圾资源化处置方案设计提供基础数据与决策依据。     

Relationships of ozone formation sensitivity with precursors emissions, meteorology and land use types, in Guangdong-Hong Kong-Macao Greater Bay Area, China

Due to the influences of precursors emissions, meteorology, geography and other factors, ozone formation sensitivity (OFS) is generally spatially and temporally heterogeneous. This study characterized detailed spatial and temporal variations of OFS in Guangdong-Hong Kong-Macao Greater Bay Area (GBA) from 2012 to 2016 based on OMI satellite data, and analyzed the relationships of OFS with precursors emissions, meteorology and land use types (LUTs). From 2012 to 2016, the OFS tended to be NO_x-limited in GBA, with the value of FNR (HCHO/NO₂) increasing from 2.04 to 2.22. According to the total annual emission statistics of precursors, NO_x emissions decreased by 33.1% and VOCs emissions increased by 35.2% from 2012 to 2016, directly resulting in OFS tending to be NO_x-limited. The Grey Relation Analysis results show that total column water (TCW), surface net solar radiation (SSR), air temperature at 2 m (T2) and surface pressure (SP) are the top four meteorological factors with the greatest influences on OFS. There are significant positive correlations between FNR and T2, SSR, TCW, and significant negative correlations between FNR and SP. In GBA, the OFS tends to be NO_x-limited regime in wet season (higher T2, SSR, TCW and lower SP) and VOCs-limited regime in dry season (lower T2, SSR, TCW and higher SP). The FNR displays obvious gradient variations on different LUTs, with the highest in “Rural areas”, second in “Suburban areas” and lowest in “Urban areas”.     

Magnetically recoverable Fe3O4@polydopamine nanocomposite as an excellent co-catalyst for Fe3+ reduction in advanced oxidation processes

Advanced oxidation processes are widely applied to removal of persistent toxic substances from wastewater by hydroxyl radicals(·OH),which is generated from hydrogen peroxide(H_2O_2) decomposition.However,their practical applications have been hampered by many strict conditions,such as iron sludge,rigid pH condition,large doses of hydrogen peroxide and Fe~(2+),etc.Herein,a magnetically recyclable Fe_3O_4@polydopamine(Fe_3O_4@PDA) coreshell nanocomposite was fabricated.As an excellent reducing agent,it can convert Fe~(3+)to Fe~(2+).Combined with the coordination of polydopamine and ferric ions,the production of iron sludge is inhibited.The minimum concentration of hydrogen peroxide(0.2 mmol/L and Fe~(2+)(0.18 mmol/L)) is 150-fold and 100-fold lower than that of previous reports,respectively.It also exhibits excellent degradation performance over a wide pH range from 3.0 to 9.0.Even after the tenth recycling,it still achieves over 99% degradation efficiency with the total organic carbon degradation rate of 80%,which is environmentally benign and has a large economic advantage.This discovery paves a way for extensive practical application of advanced oxidation processes,especially in environmental remediation.     

Sources and health risks of PM2.5-bound polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in a North China rural area

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are typical persistent organic pollutants (POPs), which have high toxicity, bioaccumulation and long-distance transfer capability. Daily variation, sources of PCBs and OCPs in PM_2.5 are rarely explored in polluted rural area. Here, the sources and health risks of the PCBs and OCPs were evaluated for 48 PM_2.5 samples collected in winter 2017 in Wangdu, a heavy polluted rural area in the North China Plain. The average diurnal and nocturnal concentrations of Σ₁₈PCBs and Σ₁₅OCPs were 1.74-24.37 and 1.77-100.49, 11.67-408.81 and 16.89-865.60 pg/m³, respectively. Hexa-CBs and penta-CBs accounted for higher proportions (29.0% and 33.6%) of clean and polluted samples, respectively. Hexachlorobenzene (HCB) was the dominant contributor to OCPs with an average concentration of 116.17 pg/m³. Hexachlorocyclohexane (ΣHCHs) and dichlorodiphenyltrichloroethane (ΣDDTs) were the other two main classes in OCPs with the average concentrations of 4.33 and 15.89 pg/m³, respectively. β-HCH and p,p’-DDE were the main degradation products of HCHs and DDTs, respectively. The principal component analysis and characteristic ratio method indicated both waste incineration and industrial activities were the main sources of PCBs, contributing 76.8% and 12.7%, respectively. The loadings of OCPs were attributed to their application characteristics and the characteristic ratio method reflected a current or past use of OCPs. Health risk assessment showed that the respiratory exposure quantity of doxin-like PCBs (DL-PCBs) and the lifetime cancer risk from airborne OCPs exposure was negligible, while the other exposure modes may pose a risk to human bodies.     

历史传染病疫情的环境与气候特征初探及对新冠肺炎疫情的思考

新型冠状病毒肺炎（COVID-19,简称“新冠肺炎”）疫情的暴发与流行对人类社会安全造成严重危害,同时也考验着世界各国公共卫生系统应对大型突发性传染病的防控能力.对历史传染病疫情暴发和流行的环境与气候特征进行总结,对于新冠肺炎疫情的科学研究及防控具有重要的参考价值.结果表明:①历史上人际传播的冠状病毒科、正粘病毒科传染病多暴发于北半球亚热带季风气候地区及冬春季节,而黄病毒科传染病多暴发在热带地区及高温多雨的夏秋季节.②全球变暖和极端天气催生影响传染病的暴发及传播.③人类对生态系统平衡的影响,迫使病毒宿主栖息地迁移和不同病毒宿主聚集,增加病毒变异概率和传染病暴发风险.在此基础上,提出了对新冠肺炎疫情的思考,认为适宜的气候因素可能利于疫情的暴发与流行,而热带国家疫情的暴发则说明需要重新审视气候、环境条件及生态因素对新型冠状病毒的影响.研究结果将为新冠肺炎疫情的防控和未来传染病疫情的预测及阻断提供参考和借鉴.      

甲型流感的流行与防控分析及其对新冠肺炎疫情的启示

目前新型冠状病毒肺炎（COVID-19）疫情在全球流行,对人类生命健康造成威胁.对甲型流感这一常见传染病进行流行特征、影响因素和防控措施分析,回顾总结全球为防控甲型流感做出的努力及相关科学研究成果,为新型冠状病毒肺炎疫情提供防控经验和研究思路.结果表明:①甲型流感呈季节性流行,受气候、社会、政治和文化等多因素影响,在低温低湿、人口密集的环境中表现出强流行性.②甲型流感防控研究工作主要包括季节性流感病毒监测、流感病毒的生态学研究、广谱中和抗体及通用疫苗的研究、应对流感大流行的病原学风险评估四方面,其中季节性流感病毒监测是制定公共卫生政策及后续研究的核心防控措施.③与甲型流感类似,新型冠状病毒肺炎疫情流行受温度等气候因素影响,同时社会、政治、文化等因素也影响其传播,亟需借鉴较成熟的甲型流感的防控经验、技术和平台.建议在加强病毒监测的同时,深入开展病毒生态学研究、病原学风险评估和药物开发,对完善疫情防控工作和预警预测未来可能出现的二次暴发及传播至关重要.研究结果将为新型冠状病毒肺炎疫情和未来传染病疫情的防控及预测预警提供参考和研究思路.      

鄱阳湖多尺度流域磷源输送特征及其生态效应

本文选取鄱阳湖梯级流域内从初级支流到湖区(香溪→架竹河→赣江→鄱阳湖)连通水系线路为研究对象,通过对鄱阳湖流域磷(P)湿沉降及径流过程进行监测,探讨鄱阳湖多尺度流域磷源输送特征及其对浮游植物群落结构的影响.结果表明:①鄱阳湖流域的P浓度呈明显的季节变化,除香溪流域外,其余流域的总磷(TP)、可溶性总磷(DTP)和磷酸根(PO_4~(3-))浓度均为枯水期较高,丰水期较低;丰水期时,TP浓度与硅藻密度存在极显著的相关关系,枯水期时,TP浓度与隐藻有极显著的相关关系.②次降雨过程研究表明:不同降雨强度下TP和PO_4~(3-)的浓度及地表径流通量的大小顺序均为:小雨中雨大雨.③丰水年和枯水年的沉降通量存在显著差异,丰水年约为枯水年的2.8倍,P的输出通量呈明显的季节性变化,丰水期大于枯水期;随流域逐级增大,但P输出贡献率未显著增加,说明逐级支流P输送并不是各级流域P的主要来源.     

华中地区黄冈市一次重度污染期间PM2.5中12种微量元素特征及来源解析

为了给华中地区大气污染防制提供数据和理论支持,于2018年1月13～24日的一次重度污染期间,利用颗粒物中流量采样器采集黄冈市大气PM_(2.5)样品48个,运用电感耦合等离子体质谱仪(ICP-MS)对样品中Li、 Be、 V、 Se、 Sr、 Mo、 Ag、 Ba、 Tl、 Th、 Bi和U这12种元素进行分析,基于正定矩阵因子分析法(PMF)对此次污染来源进行分析,并结合后向轨迹模式中的聚类分析法、潜在源分析法(PSCF)和浓度权重分析法(CWT)分析了黄冈市此次PM_(2.5)外来输送通道及潜在源分布情况.结果表明,此次污染内因是静稳高湿气象条件的出现,外因是污染的输入,总共有5种污染源,分别为燃料燃烧源(10.59%)、地壳源(24.22%)、工业源(3.16%)、燃煤源(47.57%)和交通源(14.45%).主要的气流轨迹类型有两种,短距离传输占比62.50%,长距离传输占37.50%.本次污染贡献较大的区域有湖北的中东部、湖南的东北部、安徽的西南部以及河南的南部等地,华中地区存在南北方向的传输通道.除了本地污染之外,区域传输的影响不容忽视,在秋冬季重污染应急响应期间,各地都需要控制好减排措施,联防联控是治理大气污染的关键.