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21.
Anthropogenic emissions of sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon monoxide (CO) exert significant influence on local and regional atmospheric chemistry. Temporal and spatial variability of these gases are investigated using surface measurements by the Central Pollution Control Board (India) during 2005–2009 over six urban locations in and around the Indo-Gangetic Plain (IGP) and supported using the satellite measurements of these gases. The stations chosen are Jodhpur (west of IGP), Delhi (central IGP), Kolkata and Durgapur (eastern IGP), Guwahati (east of IGP), and Nagpur (south of IGP). Among the stations studied, SO2 concentrations are found to be the highest over Kolkata megacity. Elevated levels of NO2 occur over the IGP stations of Durgapur, Kolkata, and Delhi. Columnar NO2 values are also found to be elevated over these regions during winter due to high surface concentrations while columnar SO2 values show a monsoon maximum. Elevated columnar CO over Guwahati during pre-monsoon are attributed to biomass burning. Statistically significant correlations between columnar NO2 and surface NO2 obtained for Delhi, Kolkata, and Durgapur along with very low SO2 to NO2 ratios (≤0.2) indicate fossil fuel combustion from mobile sources as major contributors to the ambient air over these regions. 相似文献
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23.
The Science of Nature - 相似文献
24.
Investigation of air pollution concentration in Kathmandu valley during winter season 总被引:1,自引:0,他引:1
KONDO Akir KAGA Akikazu IMAMURA Kiyoshi INOUE Yoshio SUGISAWA Masahiko SHRESTHA Manohar Lal SAPKOTA Balkrishan 《环境科学学报(英文版)》2005,17(6):1008-1013
The monthly concentrations of NO2, NOx, SO2 and O3 measured by a passive sampler from February 2003 to January 2004 showed that the air pollution during the winter season in Kathmandu valley was higher than the summer season. The O3 level was found the highest during April, May and June due to strong radiation. The hourly concentrations of NO2, NOx, O3 and suspended particulate matter(SPM) were also measured by automatic instruments on December 2003. Temperature at the height of 60 m and 400 m at Raniban Mountain in the northwest of Kathmandu valley was measured on February 2001 in the winter season and the average potential temperature gradient was estimated from observed temperature. Wind speed was also measured at the department of hydrology, airport section, from 18 February to 6 March 2001. It was found that the stable layer and the calm condition in the atmosphere strongly affected the appearance of the maximum concentrations of NO2 and SPM in the morning, and that the unstable layer and the windy condition in the atmosphere was considerably relevant to the decrease of air pollution concentrations at daytime. The emission amounts of NOx, HCs and total suspended particle(TSP) from transport sector in 2003 were estimated from the increasing rate of vehicles on the basis of the emission amounts in 1993 to be 3751 t/a, 30570 t/a and 1317 t/a, respectively. The diurnal concentrations in 2003 calculated by the two-layers box model reproduced the characteristics of air pollution in Kathmandu valley such as the maximum value of O3 and its time, the maximum value of NO in the morning, and the decrease of NO and NO2 at daytime. The comparison with the concentrations in 1993 calculated suggested that the main cause of air pollution was the emission from transport sector. 相似文献
25.
Carbon Management in Agricultural Soils 总被引:11,自引:0,他引:11
R. Lal 《Mitigation and Adaptation Strategies for Global Change》2007,12(2):303-322
World soils have been a major source of enrichment of atmospheric concentration of CO2 ever since the dawn of settled agriculture, about 10,000 years ago. Historic emission of soil C is estimated at 78 ± 12 Pg
out of the total terrestrial emission of 136 ± 55 Pg, and post-industrial fossil fuel emission of 270 ± 30 Pg. Most soils
in agricultural ecosystems have lost 50 to 75% of their antecedent soil C pool, with the magnitude of loss ranging from 30
to 60 Mg C/ha. The depletion of soil organic carbon (SOC) pool is exacerbated by soil drainage, plowing, removal of crop residue,
biomass burning, subsistence or low-input agriculture, and soil degradation by erosion and other processes. The magnitude
of soil C depletion is high in coarse-textured soils (e.g., sandy texture, excessive internal drainage, low activity clays
and poor aggregation), prone to soil erosion and other degradative processes. Thus, most agricultural soils contain soil C
pool below their ecological potential. Adoption of recommend management practices (e.g., no-till farming with crop residue
mulch, incorporation of forages in the rotation cycle, maintaining a positive nutrient balance, use of manure and other biosolids),
conversion of agriculturally marginal soils to a perennial land use, and restoration of degraded soils and wetlands can enhance
the SOC pool. Cultivation of peatlands and harvesting of peatland moss must be strongly discouraged, and restoration of degraded
soils and ecosystems encouraged especially in developing countries. The rate of SOC sequestration is 300 to 500 Kg C/ha/yr
under intensive agricultural practices, and 0.8 to 1.0 Mg/ha/yr through restoration of wetlands. In soils with severe depletion
of SOC pool, the rate of SOC sequestration with adoption of restorative measures which add a considerable amount of biomass
to the soil, and irrigated farming may be 1.0 to 1.5 Mg/ha/yr. Principal mechanisms of soil C sequestration include aggregation,
high humification rate of biosolids applied to soil, deep transfer into the sub-soil horizons, formation of secondary carbonates
and leaching of bicarbonates into the ground water. The rate of formation of secondary carbonates may be 10 to 15 Kg/ha/yr,
and the rate of leaching of bicarbonates with good quality irrigation water may be 0.25 to 1.0 Mg C/ha/yr. The global potential
of soil C sequestration is 0.6 to 1.2 Pg C/yr which can off-set about 15% of the fossil fuel emissions. 相似文献
26.
Jain Piyush Kumar Lanjewar Atul Rana Kunj Bihari Meena Makkhan Lal 《Environmental science and pollution research international》2021,28(4):4019-4055
Environmental Science and Pollution Research - Solar power is one of the main sources of renewable energy which helps for protecting the environmental and reducing pollution. Technologies and... 相似文献
27.
Rahul Jain Makkhan Lal Meena Manoj Kumar Sain Govind Sharan Dangayach 《International journal of occupational safety and ergonomics》2019,25(2):194-199
Purpose. In ergonomics and human factors investigations, pulling force (PF) estimation has usually been achieved using various types of biomechanical models, and independent approximation of PF was done with the help of upper extremity joints. Recently, multiple regression methods have gained importance for task-relevant inputs in predicting PF. Artificial neural networks (ANNs) also play a vital role in fitting the data; however, their use in work-related biomechanics and ergonomics is inadequate. Therefore, the current research aimed to accomplish comparative investigation of ANN and regression models by assessing their capacity to predict PF values. Methods. Multipositional PF data were acquired from 200 subjects at three different handle heights and body locations. ANN and regression models were formed using a random sample of three subsets (75% training, 15% selection, 10% validation) for proving the outcomes. Results. The comparison of ANN and regression models shows that the predictions of ANN models had a profoundly explained variance and lower root mean square difference values for the PF data at three handle heights. Conclusions. These outcomes advise that ANNs offer a precise and robust substitute for regression methods, and should be considered a useful method in biomechanics and ergonomics task assessments. 相似文献
28.
Growing dependence on coal-fired power plants for electrical generation in many countries presents ongoing environmental challenges. Burning pulverized coal in thermal power plants (TPPs) generates large amounts of fly ash (FA) that must be disposed of or otherwise handled, in an environmentally-sound manner. A possible option for dealing with fly ash is to use it as an amendment for mine spoil or other damaged soil. It has been demonstrated through studies in India and other countries that FA alone or in combination with organic or inorganic materials can be used in a productive manner for reclamation of mine spoil. The characteristics of FA, including silt-sized particles, lighter materials with low bulk density (BD), higher water holding capacity, favorable pH and significant concentrations of many essential plant nutrients, make it a potentially favorable amendment for mine spoil reclamation. Studies have indicated that the application of FA has improved the physical, chemical and biological qualities of soil to which it is applied. The release of trace metals and soluble salts from FA could be a major limitation to its application. This is particularly true of fresh, un-weathered FA or acidic FA, although perhaps not a concern for weathered/pond ash or alkaline FA. Some potential contaminants, especially metals and other salt ions, could be immobilized and rendered biologically inert by the addition of certain inorganic and organic amendments. However, in view of the variability in the characteristics of FAs that are associated with location, feed coal, combustion conditions and other factors, the suitability of a particular FA for a specific soil/mine spoil needs to be critically evaluated before it is applied in order to maximize favorable results and eliminate unexpected consequences. FA generated in India tends to be mostly alkaline, with lower levels of trace elements than are often found in FAs from other countries. The concentrations of potential chemical stressors, predominantly metals, in Indian FAs are often less than established or proposed permissible limits and are thus better suited for soil application. A major logistic limitation to the use of FA could be the cost involved in transport of ash from production to utilization sites. 相似文献
29.
30.
This paper discusses the key issues related to the supply- and demand-side options for the improvement of the environmental performance of the electricity sector in 10 countries of Asia. It also discusses the growth of the electricity sector and its contribution in the total emission of pollutants from the use of commercial energy in the selected countries. 相似文献