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351.
随着排放对环境的影响日趋严重,排放成本被纳入飞行总成本的趋势已成为必然.在对基础飞行成本模型进行改进过程中,为了准确计算飞机排放量,依据机载QAR(Quick Access Recorder,快速存取记录器)数据中表征发动机实际运行的诸多参数,准确获取排放量,进而利用改进飞行总成本模型计算实际飞行成本.同时,讨论了燃油成本、时间成本及排放成本在综合成本中所占的比例.结果表明,燃油成本占比最大,约为41.63%;时间成本约占34.13%,排放成本占比达到24.24%,超过燃油成本的1/2.由此可见,排放成本对总成本影响很大,其影响不可忽视,多方面考虑计算排放量及排放成本,可为航空公司初步评估飞机运行成本提供有效依据. 相似文献
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355.
Jinhe Wang Shuyu Sun Chongxu Zhang Chaoyang Xue Pengfei Liu Chenglong Zhang Yujing Mu Hai Wu Defa Wang Hui Chen Jianmin Chen 《环境科学学报(英文版)》2020,32(9):256-265
Atmospheric carbonyls were measured at a typical rural area of the North China Plain (NCP) from November 13 to December 24, 2017 to investigate the pollution characteristics, sources and environmental implications. Fifteen carbonyls were detected, and formaldehyde, acetaldehyde and acetone accounted for about 81% at most. The concentration of the total carbonyls in heavily polluted days was twice more than that in clean days. In contrast to other carbonyls, m-tolualdehyde exhibited relatively high concentrations in the clean days in comparison with the polluted days. The ratios of three principal carbonyls to CO showed similar daily variations at different pollution levels with significant daytime peaks. Multiple linear regression analysis revealed that the contributions of background, primary and secondary sources to three principal carbonyls showed similar variation trends from the clean level to the heavily polluted level. The OH formation rate of formaldehyde showed a similar variation trend to its photodegradation rate, reaching the peak value at noon, which is important to maintain relatively high OH levels to initiate the oxidation of various gas-phase pollutants for secondary pollutant formation at the rural site. OH radical consumption rate and ozone formation potential (OFP) calculations showed that formaldehyde and acetaldehyde were the dominant oxidative species among measured carbonyls. As for OH radical consumption, n-butyraldehyde and m-tolualdehyde were important contributors, while for ozone formation potential, n-butyraldehyde and propionaldehyde made significant contributions. In addition, the contribution of carbonyl compounds to secondary organic aerosol (SOA) formation was also important and needs further investigation. 相似文献
356.
Pablo Cicero-Fernandez Victor Torres Alberto Rosales Herman Cesar Kees Dorland Roberto Muñoz 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1586-1593
ABSTRACT The main goal of this study was to evaluate the magnitude of outdoor exposure to fine particulate matter (PM10) potentially experienced by the population of metropolitan Mexico City. With the use of a geographic information system (GIS), spatially resolved PM10 distributions were generated and linked to the local population. The PM10 concentration exceeded the 24-hr air quality standard of 150 μg/m3 on 16% of the days, and the annual air quality standard of 50 μg/m3 was exceeded by almost twice its value in some places. The basic methodology described in this paper integrates spatial demographic and air quality databases, allowing the evaluation of various air pollution reduction scenarios. Achieving the annual air quality standard would represent a reduction in the annual arithmetic average concentration of 14 μg/m3 for the typical inhabitant. Human exposure to particulate matter (PM) has been associated with mortality and morbidity in Mexico City; reducing the concentration levels of this pollutant would represent a reduction in mortality and morbidity and the associated cost of such impacts. This methodology is critical to assessing the potential benefits of the current initiative to improve air quality implemented by the Environmental Metropolitan Commission of Mexico City. 相似文献
357.
论述了对安全生产工作不能有丝毫麻痹思想,麻痹本身就是事故隐患,并以麻痹酿成事故的生动实例告诫人们麻痹是安全的大敌。 相似文献
358.
Seasonal and spatial variation of organic tracers for biomass burning in PM1 aerosols from highly insolated urban areas 总被引:1,自引:0,他引:1
B. L. van Drooge M. Fontal N. Bravo P. Fernández M. A. Fernández J. Muñoz-Arnanz B. Jiménez J. O. Grimalt 《Environmental science and pollution research international》2014,21(20):11661-11670
PM1 aerosol characterization on organic tracers for biomass burning (levoglucosan and its isomers and dehydroabietic acid) was conducted within the AERTRANS project. PM1 filters (N?=?90) were sampled from 2010 to 2012 in busy streets in the urban centre of Madrid and Barcelona (Spain) at ground-level and at roof sites. In both urban areas, biomass burning was not expected to be an important local emission source, but regional emissions from wildfires, residential heating or biomass removal may influence the air quality in the cities. Although both areas are under influence of high solar radiation, Madrid is situated in the centre of the Iberian Peninsula, while Barcelona is located at the Mediterranean Coast and under influence of marine atmospheres. Two extraction methods were applied, i.e. Soxhlet and ASE, which showed equivalent results after GC-MS analyses. The ambient air concentrations of the organic tracers for biomass burning increased by an order of magnitude at both sites during winter compared to summer. An exception was observed during a PM event in summer 2012, when the atmosphere in Barcelona was directly affected by regional wildfire smoke and levels were four times higher as those observed in winter. Overall, there was little variation between the street and roof sites in both cities, suggesting that regional biomass burning sources influence the urban areas after atmospheric transport. Despite the different atmospheric characteristics in terms of air relative humidity, Madrid and Barcelona exhibit very similar composition and concentrations of biomass burning organic tracers. Nevertheless, levoglucosan and its isomers seem to be more suitable for source apportionment purposes than dehydroabietic acid. In both urban areas, biomass burning contributions to PM were generally low (2 %) in summer, except on the day when wildfire smoke arrive to the urban area. In the colder periods the contribution increase to around 30 %, indicating that regional biomass burning has a substantial influence on the urban air quality. 相似文献
359.
铁碳微电解-Fenton法预处理苯胺基乙腈生产废水 总被引:1,自引:0,他引:1
采用铁碳微电解-Fenton法对苯胺基乙腈生产废水进行预处理实验。通过静态实验确定铁碳微电解最佳条件为铁屑投加量300 g/L,Fe/C质量比为2∶3,反应75 min,不需要调节进水pH;Fenton反应最佳条件为铁碳微电解出水pH=4,30%H2O2投加量15 mL/L,在搅拌条件下反应60 min;然后沉淀反应时调节pH为9,混凝沉淀75 min。在上述条件下通过动态实验得到系统连续反应在48 h内废水的COD和苯胺去除率在50%和70%以上,可生化性BOD5/COD也保持在0.3以上,为后续生物处理创造了良好条件。 相似文献
360.
Zhang H Mu W Hou Z Wu X Zhao W Zhang X Pan H Zhang S 《Journal of environmental science and health. Part. B》2012,47(3):153-160
By enrichment culturing of the sludge collected from the industrial wastewater treatment pond, we isolated a highly efficient nicosulfuron degrading bacterium Serratia marcescens N80. In liquid medium, Serratia marcescens N80 grows using nicosulfuron as the sole nitrogen source, and the optimal temperature, pH values, and inoculation for degradation are 30-35°C, 6.0-7.0, and 3.0% (v/v), respectively. With the initial concentration of 10 mg L?1, the degradation rate is 93.6% in 96 hours; as the initial concentrations are higher than 10 mg L?1, the biodegradation rates decrease as the nicosulfuron concentrations increase; when the concentration is 400 mg L?1, the degradation rate is only 53.1%. Degradation follows the pesticide degradation kinetic equation at concentrations between 5 mg L?1 and 50 mg L?1. Identification of the metabolites by the liquid chromatography/mass spectrometry (LC/MS) indicates that the degradation of nicosulfuron is achieved by breaking the sulfonylurea bridge. The strain N80 also degraded some other sulfonylurea herbicides, including ethametsulfuron, tribenuron-methyl, metsulfuron-methyl, chlorimuron-ethyl,and rimsulfuron. 相似文献