共查询到20条相似文献，搜索用时 203 毫秒
1.
本文根据长时间平衡单箱型模式原理 ,结合兰州市城区特有的地形及气候背景 ,利用 1 989年和 2 0 0 0年兰州市采暖期大气污染源调查资料 ,对兰州市城区采暖期SO2 、NO2 允许排放量进行了模式预测 ,并和实际排放量进行了比较 ,结果表明 :通过近十年的环境治理 ,全城区SO2 削减率从 30 .5 %下降到 1 4.6% ;城关区由 2 3.5 %下降到 6.2 % ;西固区由 5 7.7%下降到 48.1 %。NO2 削减率呈上升趋势 ,全城区削减率由 9.2 %上升到了 38.9% ,特别是西固区由60 .8%上升到 73.3% ,说明兰州市除了要继续削减SO2 排放量外 ,还要加大对NO2 的治理措施。 相似文献
2.
兰州市改善大气环境质量的总经济价值评估 总被引：15，自引：1，他引：14
以当前国际上流行的衡量环境物品经济价值的重要方法——条件价值评估法( CVM) ,针对改善兰州市大气环境质量的问题 ,用支付卡的方法设计了 5 0 0份调查问卷 ,调查了兰州市居民对改善兰州市大气环境质量的支付意愿 ( WTP)。结果表明 :若经过 1 0年的努力使兰州市大气环境达到国家二级标准 ,兰州市总共有 89.2 4 %的居民家庭有支付意愿 ,有支付意愿家庭的平均支付意愿为每年每户 98.60元 ,将这一结果推广到面上 ,得到兰州市改善大气环境质量的总经济价值为 :70 9348830元。 相似文献
3.
兰州城区大气污染物分布特征分析 总被引：10，自引：2，他引：8
利用 2 0 0 0年兰州市大气污染源调查资料 ,对影响该市的主要大气污染物的年分担率进行 1 km× 1 km 网格分析 ,结果表明 :由生活源排放的主要大气污染物年分担率呈“面”状联片分布 ,年分担率并不高 ,但影响范围较大 ;而工业源年分担率呈“点”状分散分布 ,年分担率较大 ,网格内影响较严重 ;叠加源呈“区域”壮大范围联片分布 ,年分担率最大 ,影响的范围也广 ,污染物年分担率的分布正好与污染源的位置分布相一致 ,高值区与排放量较大的污染源相对应。 相似文献
4.
郑健 《干旱区资源与环境》2013,(11):148-153
采用AHP层次分析法对乌鲁木齐市2001-2011年大气环境质量进行了评价。结果表明:2001-2011年,乌鲁木齐市大气环境质量一直处于三级标准,其中2011年大气环境质量最好,而2008年最差。大气环境质量受PM10和SO2的影响较大,而NO2的影响则较小。PM10和NO2对乌鲁木齐市大气环境质量的影响权重值逐渐变大,而SO2的影响权重值则逐渐减弱。从总体来看,乌鲁木齐市大气环境质量呈现转好的趋势,表明乌鲁木齐市近年来对大气环境的保护和治理效果较好。 相似文献
5.
以修正A值法估算宝鸡市大气环境容量,为宝鸡市大气总量控制提供科学依据。以箱模型为基本模型,利用陕西省气象台整编的1961-2008年气象资料,推导出的宏观总量控制修正A值法,宝鸡各市县A值小于国标A值。在新空气质量标准的要求下,咸阳市SO2、NOx、PM10环境容量分别为15.28×104t/a、8.76×104t/a和14.41×104t/a。为了保证各分区的环境质量,中架点源排放量与低源排放量之和应小于各分区容量,结果表明应加强对各区县中架点源与低架源的NOx控制,重点控制水泥行业和机动车的NOx排放。从整个宝鸡市的总体污染物排放来看,SO2还有剩余容量10.177×104t/a,NOx还有剩余容量1.694×104t/a。 相似文献
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7.
优化能源结构改善兰州大气环境质量的研究 总被引：1，自引：0，他引：1
特殊的地理位置和气象条件 ,使得兰州市空气污染一直比较严重。尽管排污单位加大了治理力度 ,使空气质量有了一定程度的改观 ,但为了从根本上改变大气环境质量状况 ,必须从源头抓起 ,优化能源结构。通过对兰州市能源结构和大气环境质量现状的分析 ,提高了天然气、电能和太阳能等清洁能源在能源结构中的比例 ,并运用城市多源扩散模式进行浓度预测 ,结果表明 :采取清洁能源替代措施以后 ,大气中的二氧化氮和二氧化硫按功能区划分均可达到相应的国家标准。 相似文献
8.
本文以Gauss模式为基础扩散模式 ,充分考虑了兰州市区的气象条件、地形和风场特征 ,建立了一个能够应用于长期平均浓度预测的扩散模型。并利用 98年的污染源资料和气象资料 ,对SO2 和NOX的长期平均浓度分布进行了模拟计算 ,与同期监测值相比效果较好 ,该模式能够较好的反映兰州市区的空气质量状况 ,对其他城市的长期浓度预测也有一定的借鉴作用。 相似文献
9.
为了对规划期间排入大气的SO2进行有效的控制,本文应用B-P人工神经网络方法建立了山西省运城市各县(区)人口数量、燃煤量、工业总产值和SO2排放量与SO2浓度的规划期综合预测模型,以实现在规划期间对大气的SO2的预测和控制。 相似文献
10.
在乌鲁木齐市2006年大气环境质量的基础上,分析了大气污染物排放特点:1)大气环境污染严重,呈现典型的煤烟型污染。2)污染排放高度集中,重点污染源贡献巨大。3)大气污染日趋复杂,移动源污染贡献加大。4)自然条件不利扩散,大气环境容量较小。同时结合乌鲁木齐市产业结构和能源结构,提出切实可行的综合防治对策,以促进乌鲁木齐市空气质量的全面好转。 相似文献
11.
呼和浩特市郊区土壤与蔬菜中苯并(a)芘(B_(a)P)的污染现状研究及其防治对策 总被引：1，自引：0，他引：1
呼市蔬菜区长期受工业“三废”排放的影响,农业生态系统已经受到一定程度的污染。本文通过对呼市蔬菜区土壤和蔬菜中B(a)P污染物的分析和研究,结果表明土壤中B(a)P的含量范围在5.5—63.13PPb之间,蔬菜中B(a)P含量范围在0.25—5.00PPb内,不同的蔬菜对B(a)P的吸收能力不同,土壤有一半受到B(a)P污染影响;对蔬菜的综合评价认为,除个别地方外,蔬菜大部分没有受到B(a)P污染。其污染源主要是大气污染所致,并提出了防治B(a)P污染的对策。 相似文献
12.
Inoculum Sources and Genotypic Diversity of Phytophthora infestans in Southern Flevoland,The Netherlands 总被引：2，自引：0，他引：2
M.J. Zwankhuizen F. Govers J.C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(7):667-680
Genotypic changes in populations of Phytophthora infestans in Southern Flevoland (150km2) were analysed by characterising isolates from potato refuse piles, conventional and organic potato fields, and potatoes and tomatoes in allotment gardens for mating type (1712 isolates) and DNA fingerprint pattern using probe RG57 (1048 isolates). The overall percentages of genotypes (and of isolates) that were A2 varied from 32 (4) in 1994 to 45 (56) in 1996. Among the 1048 isolates 170 different genotypes were identified, of which 138 (81%) were rare (i.e., detected in only one sampling site in the research area during 1993–1996). Many rare genotypes were encountered in organic potato fields and in allotment gardens. In 1994 and 1995, four genotypes were abundant. The highest percentages of isolates with these common genotypes were encountered in refuse piles and conventional potato fields. The common genotypes were nearly absent in 1996, suggesting that the population may have passed through a bottleneck at the transition from 1995 to 1996. The Shannon index of genotypic diversity was high in allotment gardens and in organic potato fields. For the total populations the normalised Shannon index of genotypic diversity increased from 0.34 in 1994, with weather favourable to late blight, to 0.61 in 1996, with unfavourable weather. The high numbers of rare genotypes detected every year indicate that oospores may act as an infection source in commercial potato fields. However, refuse piles were identified as the most important infection sources for commercial fields in 1994 and 1995. In 1996 disease in commercial organic fields was probably initiated by a few genotypes originating from seed tubers. In allotment gardens oospores were probably the most important infection source. 相似文献
13.
以长期采用有机污染型水灌溉的陕西交口灌区的农田土壤作为研究对象,并以气候条件、土壤条件以及耕作制度基本一致,长期采用未污染的地下水灌溉的农田土壤作为对照,分别测定土壤剖面上总有机碳含量、有机碳组成等指标,结合第二次全国土壤普查资料,分析长期采用有机污染水灌溉对土壤有机碳累积速率及有机碳密度的影响,探讨关中土壤"环境碳容量"水平及提升土壤有机碳潜力的途径。结果表明:长期采用有机污染水灌溉,土壤有机碳主要在耕层(0~20 cm)极显著地增加,且增加部分主要是活性有机碳组分,其累积速率是对照灌区的近3倍,非活性有机碳处于相对平衡状态。土壤有机碳的剖面分布发生了明显的分化现象,活性有机碳的变化比总有机碳的变化更为显著。有机污染水灌溉的土壤有机碳密度显著高于对照土壤,尤其在0~40 cm范围内其差异达极显著水平。结果证实渭河水中富含的有机污染物提升了灌溉农田土壤有机碳贮量,关中地区农田土壤环境碳容量仍未达到饱和水平,通过外源有机碳的输入,仍然有增加土壤有机碳含量的可能。 相似文献
14.
N. A. M. van Steekelenburg 《European journal of plant pathology / European Foundation for Plant Pathology》1983,89(3):75-86
The survival ofDidymella bryoniae and the incidence of ascospores in glasshouses, outdoors and under controlled conditions were studied. The fungus was able to overwinter in the open as dormant mycelium. Dry and undecomposed crop residues remained a source of infection for more than one year. Moisture and a minimum temperature between 5 and 10°C were needed for fructification. For ascospore release a high relative humidity was not sufficient, the substrate had to be moist during a short period. Ascospores could be trapped throughout day and night both outdoors and in glasshouses, but there was a marked peak during a period of 3 h in the evening. Both on days with and without rain about the same numbers of ascospores were trapped from crop residues in the open. Ascospore release was favoured by watering the plants in the glasshouse. Under controlled conditions the release of ascospores was determined by humidity and not by light or darkness. In a cucumber crop in the glasshouse the first ascospores were trapped at about the same time the first symptoms on the plants appeared. In the glasshouse with introduced diseased plant debris, particularly when the debris became wet when the plants were watered, the disease was more severe and yield was less than in a glasshouse without introduced plant debris. Airborne ascospores may cause the primary infection of a cucumber crop. Therefore, hygienic measures must be taken to eliminate plant debris as source of infection, both in glasshouses and outdoors. 相似文献
15.
Based on a database of more than 40 years of second production process and energy flow records for Maduo,Qumalai and Yushu counties,a dynamic model of the stress within grassland ecosys-tems was established using a nonlinear regression method for this source regions of the Yangtze and Yel-low Rivers.The results show that dynamic curves of stress within grassland ecosystems in the three coun-ties were in the shape of an inverted "U" during the period 1965-2007.It also revealed that the variation in actual amount of livestock inventories reflected the general trends of the stress within the grassland eco-systems in the source regions,although there were many other factors for the increase or reduction in grassland ecosystem stress. 相似文献
16.
Induction of Systemic Acquired Resistance in Pepper Plants by Acibenzolar-S-methyl against Bacterial Spot Disease 总被引：9，自引：0，他引：9
Roberto Buonaurio Luciano Scarponi Mery Ferrara Paola Sidoti Angelo Bertona 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(1):41-49
The ability of acibenzolar-S-methyl to induce resistance in pepper plants against Xanthomonas campestris pv. vesicatoria was investigated in both growth chamber and open field conditions. Growth chamber experiments showed that acibenzolar-S-methyl (300M) treatment protects pepper plants systemically and locally against X. campestris pv. vesicatoria. Evidence for this was a reduction in the number and diameter of bacterial spots and bacterial growth in planta. Systemic protection was also exerted by the acibenzolar-S-methyl acid derivative, CGA 210007, which may be produced by hydrolysis in the plant. The efficacy of acibenzolar-S-methyl was also found in open field conditions, where both leaves and fruit were protected from the disease. The highest efficacy (about 67%) was obtained by spraying the plants 6–7 times every 8–12 days with a mixture of acibenzolar-S-methyl and copper hydroxide (2.5 + 40ghl–1 active ingredient). Persistence and translocation data obtained from the growth chamber experiments revealed a persistence of acibenzolar-S-methyl lasting five days after treatment with rapid translocation and negligible levels of acid derivative formation. Since the protection exerted by acibenzolar-S-methyl against bacterial spot disease was observed when the inducer was completely degraded, it would appear to be due to SAR activation. 相似文献
17.
In order to provide an alternative for controlling bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidiae, in case of the appearance of copper/antibiotic-resistant strains of the pathogen, the field efficacy of a chitosan-based compound was compared with a copper compound on Actinidia deliciosa cv. Hayward. The 3-year trials were carried out in central Italy, in an area heavily affected by the disease. Both compounds were sprayed on the same day according to the following schedule: every 14 days, from early April to early June (a total of seven treatments), and once a month, from mid November to mid February (a total of four treatments). Chitosan did not incite any phytotoxic effect on plant and fruit and showed an overall higher level of performance than the copper compound in reducing disease symptoms throughout the 3-year trials. Chitosan significantly reduced also the presence of exudates on trunk and leader recorded at the end of winter. 相似文献
18.
ABSTRACT Spread of strawberry anthracnose, resulting from the rain splash dispersal of Colletotrichum acutatum conidia, was determined in field plots by assessing fruit disease incidence at a range of distances from an introduced point source of infected fruit with sporulating lesions. Four within-row plant densities were established in replicated plots in each of 2 years. A generalized linear model with a logit link function and binomial distribution for incidence was used to quantify the effects of distance and side of the row relative to the inoculum source, plant density treatment, and their interactions on disease incidence. At all assessment times, there was a significant (P 相似文献
19.
秦岭北麓主要河流的水质现状调查与评价 总被引：6，自引：0，他引：6
调查了秦岭北麓西自宝鸡东至潼关的10县区的28条河流,利用单污染指数法和综合污染指数法进行了评价。研究结果表明:有56.10%的河段受到不同程度的污染,其中水质严重污染的河段占7.32%;中度污染的河段占14.63%;轻污染的河段占34.15%。共有43.90%的河段水质较好,其中水质尚清洁的河段占34.15%;水质清洁的河段占9.76%。不同区县的污染特点不同。宝鸡市陈仓区和渭滨区的河段水体较清洁;西安市所辖户县、周至县、长安区主要以有机污染为主;渭南市所辖潼关、华阴和华县的有机污染和金属污染及氟污染都很严重。 相似文献
20.
XU Wenxuan 《干旱区科学》2015,7(6):852-859
Great gerbil(Rhombomys opimus) colonies, with bare soil and herbaceous plants, are conspicuous to the background environment throughout their range area. In order to quantify the engineer role of great gerbils, we investigated the plant communities of 20 active colonies in the Junggar Basin, Xinjiang, China. In areas without disturbance, desert plant communities were dominated by the shrubs with low level species richness. In burrow areas and surrounding intermediate areas, which were disturbed by great gerbils, the shrubs were suppressed with the decrease of vegetation cover and aboveground biomass. As a result, "niche gaps" were created in disturbed areas and worked as a refuge for herbaceous annuals and perennials. So the existence of great gerbils increased the overall species richness of the desert. Furthermore, herbaceous annuals and perennials are the major food source for great gerbils in spring, indicating that great gerbils have a mutually beneficial relationship with herbaceous plants. 相似文献