中国西北地区多情景土地利用优化与碳储量评估

土地利用/覆盖变化(LUCC)是导致陆地生态系统碳储量变化的主要因素,研究未来不同情景下的土地利用和碳储量变化过程,有助于制定科学的土地利用政策和提高区域陆地生态系统碳储量.研究构建了GMMOP-PLUS-InVEST模型,通过多源数据分析了2000～2020年中国西北地区土地利用和碳储量的变化特征,并预测了自然发展(ND)、经济发展(ED)、生态保护(EP)和综合发展(CD)情景下的2030年中国西北地区土地利用和碳储量.结果表明：(1)2000～2020年,草地面积减少了1 680.99×10⁴ hm²,耕地、林地、水域、湿地、建筑用地和未利用地面积分别增加了201.19×10⁴、 208.47×10⁴、 91.54×10⁴、 51.30×10⁴、 157.40×10⁴和971.09×10⁴ hm².(2)2000～2020年,土壤和地下碳储量减少,死亡有机物和地上碳储量增加,总碳储量减...     

城市火灾危险性模糊综合评估

本文建立了一多级多指标城市火灾危险性综合评估体系，且有模糊性的特点，通过引入模糊优选理论，提出了火灾危险性模糊评估方法，并将该体系和评价方法应用于青岛市三个典型区域，该体系合理，评价方法简便实用。     

覆膜滤料过滤性能分析

覆膜滤料以其高效低阻、透气性好等特点备受关注。选取4种典型的覆膜滤料,通过静态和动态过滤实验分析其阻力和效率特性,进而对覆膜滤料的过滤性能进行综合分析。结果表明:在清洁阶段,4种覆膜滤料的喷吹周期和残余阻力差异较大,粉尘剥离率平均值为83.2174%,最大偏差为2.32%;在稳定阶段,4种覆膜滤料的清灰周期、残余阻力差异减小且趋于稳定,残余阻力增长率接近且偏差均在5%以内,剥离率平均值为95.4485%,最大偏差仅0.55%。可以看出,稳定阶段覆膜滤料的种类对于阻力增长率和粉尘剥离率影响不大。通过细颗粒物过滤实验可知,评价覆膜滤料对PM2.5的过滤效果需要综合考察滤料清洁阶段和稳定阶段,可为覆膜滤料应用和评价提供指导。     

湖陆风环流对于臭氧高浓度事件影响的模拟分析

太湖流域工业发达,人口众多.湖泊激发的局地环流对于周边地区天气气候及空气污染扩散的影响值得高度关注.本文使用WRF-Chem模式,对比了Lake和Noah两种湖泊陆面过程方案对臭氧高浓度事件的模拟效果,并分析了太湖对周边地区局地环流及臭氧分布的影响.结果表明,Lake方案由于更好地引入了湖泊表面和大气之间的通量交换计算方案,其模拟值与实际观测结果有较好的匹配度.太湖和周边地区的热力差异使得太湖地区白天形成由湖区吹向陆地的湖风,湖风环流最强时在太湖-苏州方向高度可以达到4 km,最大风速达到5 m·s~(-1),对东北岸地区的影响可以穿过苏州到达城区的东北部约60 km处.太湖湖风的存在使得苏州城区的臭氧向下风向地区扩散,而湖风环流的强度不足以将湖区的臭氧输送到整个苏州城区.这导致远离太湖的城区的臭氧浓度比靠近太湖的城区低约150μg·m~(-3),臭氧浓度从靠近湖岸的城区到城区的后部再到郊区呈现出高、低、高的现象.而在夜间,受陆风影响,臭氧会在湖区上方堆积使得湖区臭氧浓度比周边陆地高约80μg·m~(-3).     

基于新型载体AMC/UASB-SCMBBR生物工艺处理印染废水的中试研究

针对泉州某印染厂实际废水(COD 800～1800 mg·L~(-1),NH~+_4-N 20～50 mg·L~(-1),pH=8～14),以两种新型载体分别作为厌氧与好氧单元中微生物固定化载体,考察了中试规模上流式厌氧污泥床反应器(UASB)与柔性悬浮载体移动床生物膜反应器(SCMBBR)组合工艺对该废水的处理效果.4个月的连续试验结果表明:①经过30 d前期调试运行该工艺系统成功启动,处理量为1.5～2.2 m~3·d~(-1)时,AMC/UASB和SCMBBR反应器对COD的去除率分别达到22%和50%,AMC/UASB反应器出现明显的产气现象,SCMBBR中载体挂膜状况良好;②启动完成后经过90 d的连续运行,当AMC/UASB和SCMBBR反应器水力停留时间分别为10.7 h和8.8 h,废水处理量为5 m~3·d~(-1)时,稳定运行阶段整个工艺废水COD去除率达到78%,出水氨氮平均浓度为3.4 mg·L~(-1);此外,整体工艺色度去除率达到65%,其中,厌氧段色度去除率达到50%左右;③通过分析计算,整个系统污泥减量达到67.7%～76.6%,该生物组合工艺具有明显的污泥减量效果.     

深圳市城区VOCs对PM2.5和O3耦合生成影响研究

为了探究珠江三角洲城市大气PM_2.5和O₃的协同污染特征,在深圳市大学城开展了秋季光化学反应活跃季大气污染加强观测.发现O₃日最大8h平均值(O₃_8h)和PM_2.5在日间具有较强的正相关关系,且O₃_8h与典型挥发性有机物(VOCs)甲醛的相关性显著高于NO₂.利用气溶胶质谱仪在线测量了亚微米气溶胶化学组成,并利用正交矩阵因子模型(PMF)对其中有机气溶胶进行来源解析,解析出5类因子,其中二次有机气溶胶(SOA)占总有机物浓度的50%.通过对污染物之间的相关性分析发现,O₃_8h和SOA具有良好的相关性,但与硝酸盐(NO₃^-)未表现出相关性,说明VOCs在深圳城区大气PM_2.5和O₃耦合生成过程中的作用比NOx明显,VOCs减排是深圳市协同控制PM_2.5和O₃污染的关键.     

北京市秋冬季环流型下的细颗粒物传输

利用Models-3/CMAQ模式系统对北京市2013~2018年秋冬季（即当年11、12月和次年1、2月份）细颗粒物（PM_2.5）进行模拟,计算北京周边4个截面的PM_2.5传输通量,结合流场、浓度的分析,总结11种大气环流型下北京市的PM_2.5传输特征.污染严重的西南（SW）和西（W）环流型下,北京地区受强烈的PM_2.5传输作用,0.6km以下南部平原的输入产生了非常强的输入累积作用,加重了北京地区PM_2.5的污染程度.污染严重的南（S）环流型下,0.6km以下东部平原和0.6km以上南部平原的输入都产生了较强的输入累积作用,京津冀东部和南部地区的污染物通过不同高度范围传输影响北京地区的PM_2.5水平.污染同样严重的均压（UM）和气旋（C）环流型下,各方向的传输都没有产生明显的输入累积作用,本地排放的削减对于污染的控制尤为重要.污染中等的东（E）、东南（SE）环流型下,北京地区在近地层（0.2km以下）通过南部平原截面对保定等城市有较大的输出通量,对北京污染具有较强的输出消散作用.污染轻的北（N）、东北（NE）和西北（NW）环流型下,北京地区在1km以下通过东部平原截面对廊坊、天津等城市有很大的输出通量,对北京污染具有很强的输出消散作用.污染轻的A环流型下,北京地区没有明显的PM_2.5输入输出现象.     

Study on the role of copper converter slag in simultaneously removing SO2 and NOx using KMnO4/copper converter slag slurry

To achieve “waste controlled by waste”, a novel wet process using KMnO4/copper converter slag slurry for simultaneously removing SO2 and NOx from acid-making tail gas was proposed. Through the solid-liquid separation for copper slag slurry, the liquid-phase part has a critical influence on removing NOx and SO2. Also, the leached metal ions played a crucial role in the absorption of SO2 and NOx. Subsequently, the effects of single/multi-metal ions on NOx removal was investigated. The results showed that the leached metal from copper converter slag (Al3+, Cu2+, and Mg2+) and KMnO4 had a synergistic effect on NOx removal, thereby improving the NOx removal efficiency. Whereas Fe2+ had an inhibitory effect on the NOx removal owing to the reaction between Fe2+ and KMnO4, thereby consuming the KMnO4. Besides, SO2 was converted to SO42? completely partly due to the liquid catalytic oxidation by metal ions. The XRD and XPS results indicated that the Fe (II) species (Fe2SiO4, Fe3O4) in copper slag can react with H+ ions with the generation of Fe2+, and further consumed the KMnO4, thereby resulting in a decrease in the NOx removal. The characterization of the slags and solutions before and after reaction led us to propose the possible mechanisms. The role of copper slag is as follows: (1) the alkaline substances in copper slag can absorb SO2 and NO2 by KMnO4 oxidation. (2) copper slag may function as a catalyst to accelerate SO2 conversion and improve NOx removal by synergistic effect between leached metal ions and KMnO4.     

Removal of elemental mercury by photocatalytic oxidation over La2O3/Bi2O3 composite

La₂O₃/Bi₂O₃ photocatalysts were prepared by impregnation of Bi₂O₃ with an aqueous solution of lanthanum precursor followed by calcination at different temperatures. The composite materials were used for the first time for the photocatalytic removal of Hg⁰ from a simulated flue gas under UV light irradiation. The results showed that the sample containing 6 wt.% La₂O₃ and calcined at 500°C has the highest dispersion of the active sites, which was promoted by the strong interaction with the support (i.e., the formation of Bi-O-La species). Since they are fully accessible on the surface, the material also exhibits excellent optical properties while the heterojunction formed in La₂O₃/Bi₂O₃ promotes the separation and migration of photoelectron-hole pairs and thus Hg⁰ oxidation efficiency is enhanced. The effects of the various factors (e.g., the reaction temperature and composition of the simulated flue gas (i.e., O₂, NO, H₂O, and SO₂)) on the efficiency of the Hg⁰ photocatalytic oxidation were investigated. The results demonstrated that O₂ and SO₂ enhanced the efficiency of the reaction while the reaction temperature, NO, and H₂O had an inhibitory effect.     

Yearly variation in characteristics and health risk of polycyclic aromatic hydrocarbons and nitro-PAHs in urban shanghai from 2010–2018

This study encompassed the regular observation of nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-PAHs (NPAHs) in particulate matter (PM) in Shanghai in summer and winter from 2010 to 2018. The results showed that the mean concentrations of ?PAHs in summer decreased by 24.7% in 2013 and 18.1% in 2017 but increased by 10.2% in 2015 compared to the data in 2010. However, the mean concentrations of ?PAHs in winter decreased by 39.7% from 2010 (12.8 ± 4.55 ng/m³) to 2018 (7.72 ± 3.33 ng/m³), and the mean concentrations of 1-nitropyrene in winter decreased by 79.0% from 2010 (42.3 ± 16.1 pg/m³) to 2018 (8.90 ± 2.09 pg/m³). Correlation analysis with meteorological conditions revealed that the PAH and NPAH concentrations were both influenced by ambient temperature. The diagnostic ratios of PAHs and factor analysis showed that they were mainly affected by traffic emissions with some coal and/or biomass combustion. The ratio of 2-nitrofluoranthene to 2-nitropyrene was near 10, which indicated that the OH radical-initiated reaction was the main pathway leading to their secondary formation. Moreover, backward trajectories revealed different air mass routes in each sampling period, indicating a high possibility of source effects from the northern area in winter in addition to local and surrounding influences. Meanwhile, the mean total benzo[a]pyrene-equivalent concentrations in Shanghai in winter decreased by 50.8% from 2010 (1860 ± 645 pg/m³) to 2018 (916 ± 363 pg/m³). These results indicated the positive effects of the various policies and regulations issued by Chinese authorities.