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481.
482.
Atmospheric emission of polychlorinated naphthalenes from iron ore sintering processes 总被引:2,自引:0,他引:2
Iron ore sintering processes constitute significant sources of dioxins, and studies have confirmed a close correlation between polychlorinated naphthalenes (PCNs) and dioxin formation. Thus, iron ore sintering processes are thought to be a potential source of PCNs, although intensive investigations on PCN emissions from sintering processes have not been carried out. Therefore, the aim of the present study was to qualify and quantify PCN emissions from nine sintering plants operating on different industrial scales. PCN concentrations ranged from 3 to 983 ng m−3 (0.4-23.3 pg TEQPCN m−3) and emission factors ranged from 14 to 1749 μg t−1 (0.5-41.5 ng TEQPCN t−1), with a geometric mean of 84 μg t−1 (2.1 ng TEQPCN t−1). The estimated annual emission of PCNs from sintering processes in China was 1390 mg TEQPCN. These figures will assist in the development of a PCN emissions inventory. Regarding emission characteristics, PCNs mainly comprised low-chlorinated homologs. The ratios of several characteristic PCN congeners were also measured and compared with those from other sources. Taken together, these results may provide useful information for identifying the sources of PCNs produced by iron ore sintering processes. 相似文献
483.
Population growth and development patterns have a significant impact on the environmental performance. The issue of concern is whether population growth or the consumption/production patterns are responsible for environmental deterioration. This paper is an attempt to capture the impact of technological development, affluence, and population on environmental performance index, while previous studies had captured the impact of these three factors on environment only through CO2 emissions. The analysis reveals that technological development and population size have a negative impact on environmental performance, whereas measures to improve affluence have a positive impact. Technological development has increased the production of energy efficient products but at the same time consumption of these products has increased manifold leading to environmental deterioration. Demographic attributes need specific attention to improve environmental performance. This paper concludes on some policy reflections on slowing the population growth as well as persuades individuals and economies to relook to their consumption and production patterns and channelize their efforts to protect the environment. 相似文献
484.
Yifang Zhu Elinor Fanning Rong Chun Yu Qunfang Zhang John R. Froines 《Atmospheric environment (Oxford, England : 1994)》2011,45(36):6526-6533
Real time number concentrations and size distributions of ultrafine particles (UFPs, diameter <100 nm) and time integrated black carbon, PM2.5 mass, and chemical species were studied at the Los Angeles International Airport (LAX) and a background reference site. At LAX, data were collected at the blast fence (∼140 m from the takeoff position) and five downwind sites up to 600 m from the takeoff runway and upwind of the 405 freeway. Size distributions of UFPs collected at the blast fence site showed very high number concentrations, with the highest numbers found at a particle size of approximately 14 nm. The highest spikes in the time series profile of UFP number concentrations were correlated with individual aircraft takeoff. Measurements indicate a more than 100-fold difference in particle number concentrations between the highest spikes during takeoffs and the lowest concentrations when no takeoff is occurring. Total UFP counts exceeded 107 particles cm−3 during some monitored takeoffs. Time averaged concentrations of PM2.5 mass and two carbonyl compounds, formaldehyde and acrolein, were statistically elevated at the airport site relative to a background reference site. Peaks of 15 nm particles, associated with aircraft takeoffs, that occurred at the blast fence were matched with peaks observed 600 m downwind, with time lags of less than 1 min. The results of this study demonstrate that commercial aircraft at LAX emit large quantities of UFP at the lower end of currently measurable particle size ranges. The observed highly elevated UFP concentrations downwind of LAX associated with aircraft takeoff activities have significant exposure and possible health implications. 相似文献
485.
Aerostat-lofted instrument and sampling method for determination of emissions from open area sources
An aerostat-borne instrument and sampling method was developed to characterize air samples from area sources, such as emissions from open burning. The 10 kg battery-powered instrument system, termed “the Flyer”, is lofted with a helium-filled aerostat of 4 m nominal diameter and maneuvered by means of one or two tethers. The Flyer can be configured variously for continuous CO2 monitoring, batch sampling of semi-volatile organic compounds (SVOCs), volatile organic compounds (VOCs), black carbon, metals, and PM by size. The samplers are controlled by a trigger circuit to avoid unnecessary dilution from background sampling when not within the source plume. The aerostat/Flyer method was demonstrated by sampling emissions from open burning (OB) and open detonation (OD) of military ordnance. A carbon balance approach was used to derive emission factors that showed excellent agreement with published values. 相似文献
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以江苏某醋厂为研究对象,使用便携式气相色谱/质谱仪实地采样,定性定量分析该厂挥发性有机物(VOCs)的排放特征及异味物质强度特征。采用美国环境保护署(USEPA)的健康风险评价模型,评估醋厂排放VOCs对周围居民的健康影响,结果表明,该厂排放的VOCs仅导致较强的感官影响,未产生明显的致癌效应。 相似文献
489.
内蒙古作为我国北方重要的生态屏障,多年来大力保护草原生态,已经基本建立了良好的生态系统。然而,内蒙古同时承担着清洁能源输出基地的职能,锡盟煤电外送基地将在2020年建成。届时,集中的开发必然导致锡盟草原的生态问题,因此亟需针对特定地区开展生态补偿问题,本文通过制度及政策分析,在排污权交易角度,提出一条解决生态补偿资金问题的新途径。并进行了制度模型的优势分析。 相似文献
490.
When considering natural attenuation as a remediation strategy at a site contaminated by a light non-aqueous phase liquid (LNAPL), it is important to consider the emission of contaminants from the source zone. A quantification of source-zone emissions is essential both for comparison with down-gradient mass fluxes to provide an estimate of fractional mass flux reduction, as well as for estimating the source lifetime. Because the spatial distribution of LNAPL at a field site is strongly dependent on both the spill circumstances and the heterogeneity of the geologic materials, which can be problematic for in-situ determination, alternative methods for estimating source-zone emissions are needed. In this work, a three-dimensional multiphase flow and transport modelling approach is used to investigate the relationship between the lateral extent of an LNAPL body and the emission of contaminants to groundwater at a contaminated site. For simulations involving an LNAPL release in an aquifer comprised of heterogeneous porosity and permeability distributions that were generated geostatistically, it is shown that a simple linear relationship exists between the lateral extent of the LNAPL body in the capillary fringe and the emission to the aqueous phase. The parameters describing the relationship are found to be linear functions of the groundwater flow velocity and the vertical infiltration rate. This site-specific relationship provides a simple method to estimate contaminant emissions to groundwater at LNAPL contaminated sites. 相似文献