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151.
The main emissions from coal combustion at thermal power plants are carbon dioxide (CO2), nitrogen oxides, sulfur oxides, chlorofluorocarbons (CFCs), and airborne inorganic particles such as fly ash and soot; CO2, methane, and CFCs are greenhouse gases. These emissions are considered to be partially responsible for harmful global climate change. This review summarizes the status of thermal power plants in India and their various types of emissions that directly or indirectly produce harmful effects on the environment and human health. Moreover, it focuses on various types of preventive measures used to avoid/minimize emissions. 相似文献
152.
Aniza K. Verma Avanish K. Srivastava Beer Singh Dilip Shah Smriti Shrivastava Chandra Kant P. Shinde 《Chemosphere》2013,90(8):2254-2260
1-(4-Chlorophenyl))-N-hydroxymethanimine and cyclohexyl-N-hydroxymethanimine were synthesized and a well-established oxime, i.e., 2-[(hydroxyimino)methyl]-1-methylpyridinium chloride was purchased. Thereafter; all were loaded over Al2O3 using incipient wetness technique. The prepared systems were characterized using surface area analyzer, scanning electron microscope, energy dispersive X-ray spectrophotometer, Fourier transform infrared spectrophotometer and thermogravimetric analyzer. Kinetics of the degradation of sarin (GB) and simulant, i.e. diethylchlorophosphate (DEClP) was studied over synthesized oxime impregnated Al2O3 and results were compared with well reported oxime impregnated Al2O3. Kinetics of reaction was found to be following the pseudo first order reaction kinetics. The order of reactivity of the prepared systems was found to be cyclohexyl-N-hydroxymethanimine/Al2O3 > 1-(4-chlorophenyl)-N-hydroxymethanimine/Al2O3 > 2-[(hydroxyimino)methyl]-1-methylpyridinium chloride/Al2O3 > Al2O3. From the reaction kinetics it was observed that the reaction with DEClP was faster than with GB. Cyclohexyl-N-hydroxymethanimine/Al2O3 was found to be the most reactive system with half-life of 0.94 and 15 h for DEClP and GB respectively. 相似文献
153.
Amal Chandra Das Hemanta Nayek Arunabha Chakravarty 《Environmental monitoring and assessment》2012,184(12):7453-7459
An experiment was conducted under laboratory conditions to investigate the effect of two systemic herbicides, viz. pendimethalin (a dinitroaniline) and quizalofop (an arylphenoxy propionic acid) at their recommended field application rates (1.0?kg and 50?g active ingredient per hectare, respectively), either separately or in a combination, on growth and activities of phosphate-solubilizing microorganisms in relation to their effects on biochemical transformations and availability of organic carbon, total and available phosphorus in a Typic Haplustept soil of West Bengal, India. Application of herbicides, in general, significantly stimulated the growth and activities of phosphate-solubilizing microorganisms which increased microbial biomass resulting in higher accumulation of oxidizable organic carbon, total and available phosphorus in soil as compared to untreated control. The combined application of both the herbicides highly stimulated the proliferations of phosphate-solubilizing microorganisms, while pendimethalin alone significantly accentuated phosphate-solubilizing capacities 36.4% as compared to untreated control and retained highest amount of total phosphorus due to greater microbial activities in soil. The separate application of quizalofop also manifested an induced effect on the proliferations of phosphate-solubilizing microorganisms and accounted significant amounts of organic carbon and available phosphorus in the soil system. The results of the present study thus indicated that the cited herbicides at their field application rates can be safely used to eradicate weeds in the crop fields. 相似文献
154.
155.
A multivariate time series approach vector autoregression (VAR) along with impulse response function and variance decomposition
technique has been employed to look into the interrelationship among O3, NO, NO2, and volatile organic compounds (VOCs, namely, benzene, ethylbenzene, toluene, and xylene in the present study) using 3 months
long continuous time series data of 1 h average concentration of these pollutants at one of the traffic sites in Delhi, India.
It is found that the VAR of order 2 (i.e., past two lagged values of 1 h interval) is sufficient to represent the observed
time series at the station studied. The impulse response function and variance decomposition analysis indicate that O3 concentration shows an immediate rise and persists for a longer duration (typically 8–10 h) once the impulse of NO2, benzene, ethylbenzene, or xylene is given in the ambient environment. However, in case of toluene, the reverse effect has
been observed. Since O3 forms in the troposphere due to photolysis of NO2, it is not surprising that its impulse triggers O3 formation in the ambient environment. However, in case of VOCs, this has been attributed to their tendency to show higher
inclination toward intermediary reactions leading to the formation of O3 rather than their (VOCs) reaction with O3. Among VOCs, only toluene has been observed to show higher inclination toward its reaction with O3. Apart from this, variance decomposition technique also reveals that the relation of NO with NO2 is more important than the relation of NO with O3 creating a conducive atmosphere for O3 formation in the present scenario. Thus, the multivariate time series approach provides significant insight about the role
played by the dominant individual VOCs and NO
x
in influencing the O3 concentration in ambient urban atmosphere whereas a photochemical modeling approach gives an overall view of NO
x
and VOCs behavior with respect to O3 by using the O3 isopleth technique. 相似文献
156.
Deepak Singh Amit Prakash A. K. Srivastava Krishan Kumar V. K. Jain 《Environmental monitoring and assessment》2013,185(2):1873-1882
The acoustic environment in urban areas has gained prominence in recent times due to rapid industrial and commercial development in metropolitan cities. Various attempts have been made to predict and model the trends in urban ambient noise levels using different statistical and dynamic models. The present study makes an attempt to examine the role of meteorological parameters affecting the ambient noise levels in Delhi. The results show significant improvement in overall noise scenario of Delhi since the introduction of compressed natural gas vehicles in public transport of Delhi. The noise level is significantly reduced by high vegetation cover as well as by low relative humidity over Delhi. The regression models developed for the present study clearly show the significant contribution of meteorological parameters in governing the ambient noise levels in Delhi. 相似文献
157.
为研究天津市大气气溶胶中氮的来源,分析了2016年夏、冬两季昼夜采集的细颗粒物气溶胶(PM2.5)中无机离子浓度和氮同位素组成(δ15N).结果显示:天津市冬季平均PM2.5质量浓度(207 μg/m3)远高于夏季(40.1 μg/m3),冬季PM2.5的δ15N值(+5.1‰)低于夏季(+10.7‰),即夏季PM2.5较冬季更富集15N;夏季PM2.5中NH4+的平均浓度高于c(NO3–),但是冬季NO3–浓度最高,其次是c(NH4+)>c(SO42–);此外,通过对比昼夜样品,夏季PM2.5中氮含量和氮同位素组成在昼夜均表现出明显差异,而冬季不明显.结果表明,天津市夏季气溶胶中含氮化合物在昼夜受海陆风的影响,即白天受海洋气溶胶影响较大而夜间则为陆源气溶胶物质影响,然而冬季受东亚季风的影响削弱了海陆风对海陆间大气气溶胶的交换作用,且在冬季化石燃料燃烧源氮贡献较大. 相似文献
158.
Sorption kinetics and leachability of heavy metal from the contaminated soil amended with immobilizing agent (humus soil and hydroxyapatite) 总被引:2,自引:0,他引:2
Release of heavy metals onto the soil as a result of agricultural and industrial activities may pose a serious threat to the environment. This study investigated the kinetics of sorption of heavy metals on the non-humus soil amended with (1:3) humus soil and 1% hydroxyapatite used for in situ immobilization and leachability of heavy metals from these soils. For this, a batch equilibrium experiment was performed to evaluate metal sorption in the presence of 0.05 M KNO(3) background electrolyte solutions. The Langmuir isotherms applied for sorption studies showed that the amount of metal sorbed on the amended soil decreased in the order of Pb(2+)>Zn(2+)>Cd(2+). The data suggested the possibility of immobilization of Pb due to sorption process and immobilization of Zn and Cd by other processes like co-precipitation and ion exchange. The sorption kinetics data showed the pseudo-second-order reaction kinetics rather than pseudo-first-order kinetics. Leachability study was performed at various pHs (ranging from 3 to 10). Leachability rate was slowest for the Pb(2+) followed by Zn(2+) and Cd(2+). Out of the metal adsorbed on the soil only 6.1-21.6% of Pb, 7.3-39% of Zn and 9.3-44.3% of Cd leached out from the amended soil. 相似文献
159.
160.
The agriculture industry is significantly exposed to the impacts of climate change, and is also responsible for contributing extensive greenhouse gas emissions. As a way of responding to both adaptation and mitigation challenges within the industry, this article examines how community-based climate change adaptation initiatives might provide mitigation outcomes in the agriculture sector in Timor-Leste. Beginning with an exploration of nation-wide institutional responses to climate change, the study utilises interviews, field observations and document analysis to examine an extensive community-based adaptation program in two districts in Timor-Leste focused on increasing the resilience of the agriculture sector and the livelihoods of poor rural farmers. Analysis of this program reveals a largely synergistic relationship between adaptation measures focused on land and water management and agriculture and their corresponding greenhouse gas mitigation potential, including co-benefits such as soil/atmospheric carbon sequestration, reduced emissions, soil nitrification and reduced use of inorganic fertilisers. Community-based adaptation programs in the agriculture sector have a significant influence on mitigation outcomes, which is often overlooked in community-based programs. The adaptation program in Timor-Leste has provided useful insights into the inter-relationships between adaptation and mitigation at the community level, which could be further supported and scaled-up in other Southeast Asia countries and elsewhere. 相似文献