灰霾天气的形成与灰霾监测

指出了灰霾天气越来越严重,对气候和生态系统造成了一系列影响,提出了对灰霾中各种气体含量的监测方法,分析了影响灰霾天气形成的因素,以供相关部门参考。     

灰霾主要研究方向综述

从影响灰霾天气的气象因素、灰霾天气的污染特征、灰霾观测界定、单个霾粒子研究、灰霾数值模拟几个方面,归纳了国内外灰霾的主要研究成果,并提出了今后灰霾研究的发展趋势。     

试论中国灰霾天气的成因、危害及控制治理

指出了随着工业的快速发展和城市机动车辆的迅速增多,城市大气悬浮物等污染物的排放逐年明显增加,使得能见度显著降低,严重影响了部分城市居民的日常生产生活。灰霾天气已经被列为灾害性天气,同时受太阳辐射和人类排放作用的影响,灰霾现象的增长与城市热岛强度的增加呈现明显的正相关。简要阐述了灰霾天气的成因、危害及控制治理措施。     

在线气体组分及气溶胶监测系统对灰霾天气的分析

利用在线气体组分及气溶胶监测系统(MARGA ADI 2080)实时连续监测了大气颗粒物PM2.5中水溶性组分和气体中相关无机物小时平均质量浓度,并结合PM2.5的实时数据以及气象资料对监测到的灰霾天气进行了分析。结果表明:在2013年12月3日至10日上海市崇明县东平国家森林公园老烧烤场的灰霾天气监测过程中,二次污染是灰霾形成的主因。     

武汉灰霾天气气候特征及成因讨论

利用武汉市地面气象观测站2008～2013年的霾实际观测资料以及08时高空探测规定层气温资料,对霾日进行了订正,分析了武汉市灰霾天气的时间分布和气象要素影响因子。结果表明：武汉市秋冬季灰霾较为严重,2013年霾日剧增,是由于细颗粒物污染物的排量加重,另外也是由于稳定的气象条件及全国大范围的雾霾天气的影响。     

灰霾元凶PM_(2.5)源解析及其环境评价标准建立综述

以环境影响评价工作中PM2.5相关工作内容为视角,总结了造成大气灰霾天气的元凶PM2.5的相关研究进展,内容包括其污染源分类、城市大气PM2.5分布特征及源解析、国内外控制PM2.5的环境质量标准制定历程等。对我国环境影响评价中应对PM2.5污染的相关工作做了展望。     

PM_(2.5)的分布特征及治理方法研究

随着中国社会经济的不断发展,人们的生活水平日益提高,社会及大众对空气环境的质量愈加重视。PM2.5作为灰霾的主要成分,是衡量空气质量优劣的一个重要指标,越来越受到重视。特别是2013年以来,大陆中东部反复出现灰霾天气,给工业生产、交通运输和群众的健康带来了不良的影响。针对PM2.5的危害及相关治理方法进行了分析探讨,为治理大气污染提供可鉴之处,同时也为国家生态文明建设贡献一份力量。     

发挥城市森林独特作用整治城市空气质量

随着我国工业化、城镇化发展步伐加快,城市的生态环境压力日益增大。城市空气污染、水体污染、热岛效应等环境问题给城市发展带来了许多负面效应和经济损失,据统计,2004年我国城市由于空气污染共造成近35,8万人死亡,造成的经济损失高达1527．4亿元。2011年末,北京市连续数目的灰霾天气让PM2．5（直径小于等于2.5微米的颗粒物）引起了社会各界热议,PM25成了大街小巷的热点话题,群众对空气质量问题空前关注。     

耐火材料生产废气治理工程实例分析

指出了随着我国各城市灰霾天气的增多,大气污染加剧,对涉"污"企业的管理将更加严格。以某耐火材料生产企业生产废气的处理工艺为实例,分析了其良好的经济效益、环保效益和社会效益。     

襄阳市灰霾天气成因及对策探讨

根据近3年的气象和环保观测资料,从自然原因(地形地貌、气象)和社会原因(机动车、工业化进程、建筑施工)两大方面进行了分析,揭示了襄阳灰霾天气的成因,在此基础上提出了相应的防治对策。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.