乌鲁木齐不同功能区昼间臭氧浓度变化特征分析

为了研究乌鲁木齐市昼间的近地层大气臭氧浓度变化特征,利用靛蓝二磺酸钠分光光度法(IDS法)对乌鲁木齐市不同功能区在采暖期前期、采暖期与采暖期后期昼间的小时臭氧浓度进行监测,分析与温度、太阳辐射、相对湿度的相关性。结果表明:乌鲁木齐市不同功能区昼间的小时臭氧浓度变化具有明显的"单峰型"变化规律,从早上09:00开始,臭氧浓度明显上升,最高的小时臭氧浓度出现在午后,其中,交通区、工业区昼间的小时臭氧浓度较高。不同时间段臭氧总平均浓度依次为采暖期前期>采暖期后期>采暖期,不同时间段昼间的小时臭氧浓度变化与太阳辐射、温度呈显著的正相关性,与相对湿度呈显著的负相关性。     

菏泽市PM2.5碳组分季节变化特征

于2015年8月到2016年4月在菏泽市城区采集PM_(2.5)颗粒,利用热/光碳分析仪测定了颗粒物中8种碳组分,获得了有机碳(OC)和元素碳(EC)的质量浓度,分析了OC与EC的比值、相关性,使用OC/EC比值法估算了二次有机碳(SOC)的浓度,并使用主成分分析法研究8种碳组分含量.结果表明,(1)PM_(2.5)中OC、EC的年质量浓度变化范围分别为1.2~60.6μg·m~(-3)、0.6~24.8μg·m~(-3),OC/PM_(2.5)、EC/PM_(2.5)的季节分布特征相似:冬季春季秋季夏季;(2)OC/EC的年平均值为2.6±1.0,春夏秋冬OC、EC的相关系数分别为0.91、0.56、0.86、0.75,估算的SOC年平均浓度为(4.7±5.0)μg·m~(-3);(3)不同季节8种碳组分质量分数均为EC1最高,EC3最低.主成分分析结果显示,春秋冬这3个季节碳组分的主要来源为燃煤、机动车和生物质燃烧.     

内蒙古河套灌区不同盐碱程度土壤CH4吸收规律

土壤盐碱化严重威胁土地可持续利用和温室气体排放.本研究选择内蒙古河套灌区3种盐碱土壤［S1：盐化土壤,电导率（EC）4.80 dS·m^-1;S2：强度盐碱土壤,电导率（EC）2.60 dS·m^-1;S3：轻度盐碱土壤,电导率（EC）0.74 dS·m^-1］.利用静态暗箱法野外原位观测研究盐碱土壤甲烷（CH₄）吸收规律.结果表明,不同盐碱程度土壤CH₄吸收每年均存在显著差异,2014年生长季（F=18.0,P<0.001）,2015年生长季（F=23.6,P<0.001）和2016年生长季（F=28.4,P<0.001）.轻度盐碱土壤CH₄累积吸收量最高,盐化土壤累积吸收量最低.随土壤盐碱程度加重,土壤CH₄累积吸收量降低.轻度盐碱土壤CH₄累积吸收量在2014~2016年3个生长季（4~10月）分别为150.0、119.6和99.9 mg·m^-2;重度盐碱土壤CH₄累积吸收量比轻度盐碱土壤分别降低27%、28%和19%;盐化土壤CH₄累积吸收量比轻度盐碱土壤分别降低35%、35%和53%.冗余分析表明,盐碱土壤CH₄吸收通量与土壤EC的投影在第一主成分轴正方向和反方向,土壤EC越高,CH₄吸收通量越低.土壤电导率EC是调控盐碱土壤CH₄吸收的关键因子,相关系数r为-0.8809（P<0.01,n=9）.     

Passive aeration composting of chicken litter: Effects of aeration pipe orientation and perforation size on losses of compost elements

A passive aeration composting study was undertaken to investigate the effects of aeration pipe orientation (PO) and perforation size (PS) on some physico-chemical properties of chicken litter (chicken manure + sawdust) during composting. The experimental set up was a two-factor completely randomised block design with two pipe orientations: horizontal (Ho) and vertical (Ve), and three perforation sizes: 15, 25 and 35 mm diameter. The properties monitored during composting were pile temperature, moisture content (MC), pH, electrical conductivity (EC), total carbon (C_T), total nitrogen (N_T) and total phosphorus (P_T). Moisture level in the piles was periodically replenished to 60% for efficient microbial activities. The results of the study showed that optimum composting conditions (thermophilic temperatures and sanitation requirements) were attained in all the piles. During composting, both PO and PS significantly affected pile temperature, moisture level, pH, C_T loss and P_T gain. EC was only affected by PO while N_T was affected by PS. Neither PO nor PS had a significant effect on the C:N ratio. A vertical pipe was effective for uniform air distribution, hence, uniform composting rate within the composting pile. The final values showed that PO of Ve and PS of 35 mm diameter resulted in the least loss in N_T. The PO of Ho was as effective as Ve in the conservation of C_T and P_T. Similarly, the three PSs were equally effective in the conservation of C_T and P_T. In conclusion, the combined effects of PO and PS showed that treatments Ve35 and Ve15 were the most effective in minimizing N_T loss.     

Environmental assessment of different management options for individual waste fractions by means of life-cycle assessment modelling

Several alternatives exist for handling of individual waste fractions, including recycling, incineration and landfilling. From an environmental point of view, the latter is commonly considered as the least desirable option. Many studies based on life-cycle assessment (LCA) highlight the environmental benefits offered by incineration and especially by recycling. However, the landfilling option is often approached unjustly in these studies, maybe disregarding the remarkable technological improvements that landfills have undergone in the last decades in many parts of the world.This study, by means of LCA-modelling, aims at comparing the environmental performance of three major management options (landfilling, recycling and incineration or composting) for a number of individual waste fractions. The landfilling option is here approached comprehensively, accounting for all technical and environmental factors involved, including energy generation from landfill gas and storage of biogenic carbon. Leachate and gas emissions associated to each individual waste fraction have been estimated by means of a mathematical modelling. This approach towards landfilling emissions allows for a more precise quantification of the landfill impacts when comparing management options for selected waste fractions.Results from the life-cycle impact assessment (LCIA) show that the environmental performance estimated for landfilling with energy recovery of the fractions “organics” and “recyclable paper” is comparable with composting (for “organics”) and incineration (for “recyclable paper”). This however requires high degree of control over gas and leachate emissions, high gas collection efficiency and extensive gas utilization at the landfill. For the other waste fractions, recycling and incineration are favourable, although specific emissions of a variety of toxic compounds (VOCs, PAHs, NO_x, heavy metals, etc.) may significantly worsen their environmental performance.     

Influence of grain size on species-habitat models

High resolution remote sensing data facilitate the use of small-scale habitat features such as trees or hedges in the analysis of species-habitat relationships. Such data potentially enable more accurate species-habitat mapping than lower resolution data. Here, for the first time, we systematically investigated this hypothesis by altering the spatial resolution from 1 m up to 1000 m grain size in species-habitat models of 13 bird species. The study area covered the Nidda river catchment in central Germany, a large heterogeneous landscape of 1620 km². A high resolution habitat map of the area was converted to coarser spatial and thematic resolutions in seven steps. We investigated how model performance responded to grain size, and we compared the differential effects of spatial resolution and thematic resolution on model performance. Explained deviance (D²) of the bird models generally decreased with coarser spatial resolution of the data, although it did not decrease monotonically in all species. On average across all species, model D² decreased from 41.5 at 1 m grain size to 15.9 at 1000 m grain size. Ten species were best modelled at 1 m, two species at 3 m and one species at 32 m grain size. Model performance degraded continuously with increasing grain size, both in habitat generalist and habitat specialist bird species, and was systematically lower in habitat generalists. The higher model performance observed at finer grain sizes was most likely caused by the combination of three factors: (1) high spatial accuracy of bird records and (2) a more precise location and delineation of habitat features and, (3) to a lesser degree, by more habitat types differentiated in maps of finer resolution. We conclude that higher spatial and thematic resolution data can be essential for deriving accurate predictions on bird distribution patterns from species-habitat models. Especially for bird species that are sensitive to specific land-use types or to small-scaled habitat features, a grain size of 1-3 m seems most promising.     

北京市秋季大气气溶胶质量浓度谱分布特征的观测研究

为了研究不同天气形势和气象要素对不同粒径段的大气气溶胶质量浓度谱分布的影响,2010年秋季在北京市采用空气动力学粒径仪对0.5 ～20 μm的大气颗粒物进行了为期2个月的连续观测.结果表明,在不同天气形势和气团运动下,质量浓度谱分布差异明显.受到西北气流影响,在质量浓度较小的清洁天气,谱分布主要集中在粗粒径段(清洁天气).当天气以静稳为主,颗粒物质量浓度值中等偏高时,粗细粒径气溶胶分布中出现谱值相近的高峰(中等浑浊天气).在受到西南气流主要影响的高质量浓度的观测日中,细粒径气溶胶在谱分布中占主要地位(高浑浊天气).在相同气团影响的天气下,昼夜间质量浓度谱分布的谱型变化趋势一致.清洁天气保持了粗粒径段的单峰分布,中等浑浊和高浑浊天气呈双峰分布.清洁天气细粒径段谱值受光化学反应影响在日间略高于夜间.中等浑浊天气中质量浓度的谱值在夜间受相对湿度和温度变化影响有显著增加.高浑浊天气下,昼夜温湿差别小,谱分布未出现明显变化.     

天水市大气降尘组成特征及表面电性模拟研究

对甘肃省天水市麦积镇大气降尘粒度分布及主要矿物组成进行了分析,并以实际降尘ζ电位作为参照,根据降尘中主要矿物组成的质量百分比,提出了计算法和混合法两种模拟大气降尘在水溶液中表面电性的方法.结果表明,麦积地区大气降尘属于可吸入颗粒粒度尺寸范畴,其主要矿物组成与质量含量为：石英（57.08%）、方解石（27.79%）、钠长石（10.29%）、白云母（4.84%）. 大气降尘在纯水中呈电负性,且ζ电位随着水溶液pH增加而减小.通过对比实际降尘与拟合方法所得到的ζ电位,发现两种拟合方式与实际降尘的ζ电位具有相似的变化趋势.降尘中矿物组成主导着降尘表面电位的大小和变化趋势,其对降尘表面电位的贡献率是最主要的.     

两级序批式生物膜法对厌氧消化液的处理研究

采用两级序批式生物膜法(SBBR)处理猪场废水厌氧消化液,考察了不同类型的填料以及填料的不同组合方式对污染物的去除效果。试验结果表明:组合3(1级反应器中投加碳素纤维填料,2级反应器中投加组合填料)COD去除能力较好,可达93.7%,组合1(1级,2级反应器中均投加碳素纤维填料)NH4+-N和TN去除率最高,分别为69.2%、70.4%;此外对运行过程中的DO浓度和pH值的变化情况进行监测,DO浓度受有机物降解和硝化反应的共同影响,pH值受曝气量的影响较多。因此,可以通过DO浓度和pH值来判断反应系统中污染物的变化情况和反应所处阶段。     

东北地区粮食生产及其可持续性因子分析

通过对东北地区耕地面积、粮食单产及总产的时间序列分析，揭示了该地区粮食生产发展趋势，并结合粮食生产发展的影响因子分析，探该区粮食生产可持续发展的影响因子，指出今后提高粮食生产的途径。