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1.
Gsnvksn Swamy S.M. Shiva Nagendra Uwe Schlink 《Journal of the Air & Waste Management Association (1995)》2017,67(10):1080-1091
The combined action of urbanization (change in land use) and increase in vehicular emissions intensifies the urban heat island (UHI) effect in many cities in the developed countries. The urban warming (UHI) enhances heat-stress-related diseases and ozone (O3) levels due to a photochemical reaction. Even though UHI intensity depends on wind speed, wind direction, and solar flux, the thermodynamic properties of surface materials can accelerate the temperature profiles at the local scale. This mechanism modifies the atmospheric boundary layer (ABL) structure and mixing height in urban regions. These changes further deteriorate the local air quality. In this work, an attempt has been made to understand the interrelationship between air pollution and UHI intensity at selected urban areas located at tropical environment. The characteristics of ambient temperature profiles associated with land use changes in the different microenvironments of Chennai city were simulated using the Envi-Met model. The simulated surface 24-hr average air temperatures (11 m above the ground) for urban background and commercial and residential sites were found to be 30.81 ± 2.06, 31.51 ± 1.87, and 31.33 ± 2.1ºC, respectively. The diurnal variation of UHI intensity was determined by comparing the daytime average air temperatures to the diurnal air temperature for different wind velocity conditions. From the model simulations, we found that wind speed of 0.2 to 5 m/sec aggravates the UHI intensity. Further, the diurnal variation of mixing height was also estimated at the study locations. The estimated lowest mixing height at the residential area was found to be 60 m in the middle of night. During the same period, highest ozone (O3) concentrations were also recorded at the continuous ambient air quality monitoring station (CAAQMS) located at the residential area.
Implications: An attempt has made to study the diurnal variation of secondary pollution levels in different study regions. This paper focuses mainly on the UHI intensity variations with respect to percentage of land use pattern change in Chennai city, India. The study simulated the area-based land use pattern with local mixing height variations. The relationship between UHI intensity and mixing height provides variations on local air quality. 相似文献
2.
Nagendra H 《Journal of environmental management》2012,95(1):108-113
Information on changes in forest structure and composition is required for informed, adaptive management and conservation. As the collection of such information requires field studies that are expensive, difficult, and time consuming, the prioritization of metrics can be of significant value. This study evaluates a number of metrics used to assess changes in forest structure and composition for a set of 59 forests in five countries - Kenya, India, Nepal, Uganda and USA. Changes in tree density are significantly positively correlated with changes in species richness, and changes in sapling/shrub density are significantly positively correlated with changes in species richness. Thus, rapid assessments of tree density change can be used to prioritize locations where there may be rapid deterioration in tree diversity, where the collection of detailed information on changes in species composition may be prioritized. Changes in tree density do not reflect changes in shrub and sapling density. The shrub and sapling layer appears to respond differently to human or natural disturbances compared to the tree layer, and may require separate assessment. Changes in tree DBH and tree height are not completely congruent, indicating that measurements of DBH and height may be required to accurately estimate changes in above ground carbon storage over time, for programs such as REDD that provide payment for carbon sequestration services. 相似文献
3.
Artificial neural network based carbon monoxide persistence models for episodic urban air quality management 总被引:1,自引:0,他引:1
This paper describes the development of artificial neural network (ANN) based carbon monoxide (CO) persistence (ANNCOP) models
to forecast 8-h average CO concentration using 1-h maximum predicted CO data for the critical (winter) period (November–March).
The models have been developed for three 8-h groupings of 10 p.m. to 6 a.m., 6 a.m. to 2 p.m. and 2–10 p.m., at two air quality control regions (AQCRs) in Delhi city, representing an urban intersection and an arterial road consisting
heterogeneous traffic flows. The result indicates that time grouping of 2–10 pm is dominantly affected by inversion conditions and peak traffic flow. The ANNCOP model corresponding to this grouping predicts
the 8-h average CO concentrations within the accuracy range of 68–71%. The CO persistence values derived from ANNCOP model
are comparable with the persistence values as suggested by the Environmental Protection Agency (EPA), USA. This work demonstrates
that ANN based model is capable of describing winter period CO persistence phenomena. 相似文献
4.
Nina Rønsted Seana K. Walsh Margaret Clark Merlin Edmonds Tim Flynn Scott Heintzman Alexander Loomis David Lorence Uma Nagendra Ben Nyberg Michael Opgenorth Lauren Weisenberger Adam Williams Dustin Wolkis Kenneth R. Wood Matthew Keir 《Conservation biology》2022,36(4):e13896
The International Union for Conservation of Nature's Red List of Threatened Species (IUCN Red List) is the world's most comprehensive information source on the global conservation status of species. Governmental agencies and conservation organizations increasingly rely on IUCN Red List assessments to develop conservation policies and priorities. Funding agencies use the assessments as evaluation criteria, and researchers use meta-analysis of red-list data to address fundamental and applied conservation science questions. However, the circa 143,000 IUCN assessments represent a fraction of the world's biodiversity and are biased in regional and organismal coverage. These biases may affect conservation priorities, funding, and uses of these data to understand global patterns. Isolated oceanic islands are characterized by high endemicity, but the unique biodiversity of many islands is experiencing high extinction rates. The archipelago of Hawaii has one of the highest levels of endemism of any floristic region; 90% of its 1367 native vascular plant taxa are classified as endemic. We used the IUCN's assessment of the complete single-island endemic (SIE) vascular plant flora of Kauai, Hawaii, to assess the proportion and drivers of decline of threatened plants in an oceanic island setting. We compared the IUCN assessments with federal, state, and other local assessments of Kauai species or taxa of conservation concern. Finally, we conducted a preliminary assessment for all 1044 native vascular plants of Hawaii based on IUCN criterion B by estimating area of occupancy, extent of occurrence, and number of locations to determine whether the pattern found for the SIE vascular flora of Kauai is comparable to the native vascular flora of the Hawaiian Islands. We compared our results with patterns observed for assessments of other floras. According to IUCN, 256 SIE vascular plant taxa are threatened with extinction and 5% are already extinct. This is the highest extinction risk reported for any flora to date. The preliminary assessment of the native vascular flora of Hawaii showed that 72% (753 taxa) is threatened. The flora of Hawaii may be one of the world's most threatened; thus, increased and novel conservation measures in the state and on other remote oceanic islands are urgently needed. 相似文献
5.
Samir Kumar Khanal Wen-Hsing Chen Ling Li Shihwu Sung 《Water environment research》2006,78(2):110-117
The goal of the proposed project was to develop an anaerobic fermentation process that converts negative-value organic wastes into hydrogen-rich gas in a continuous-flow reactor under different operating conditions, such as hydraulic retention time (HRT), heat treatment, pH, and substrates. A series of batch tests were also conducted in parallel to the continuous study to evaluate the hydrogen conversion efficiency of two different organic substrates, namely sucrose and starch. A heat shock (at 90 degrees C for 15 minutes) was applied to the sludge in an external heating chamber known as a sludge activation chamber, as a method to impose a selection pressure to eliminate non-spore-forming, hydrogen-consuming bacteria and to activate spore germination. The experimental results showed that the heat activation of biomass enhanced hydrogen production by selecting for hydrogen-producing, spore-forming bacteria. The batch feeding at a shorter HRT of 20 hours (or higher organic loading rate) favored hydrogen production, whereas, at a longer HRT of 30 hours, methane was detected in the gas phase. The major organic acids of hydrogen fermentation were acetate, butyrate, and propionate. Up to 23.1% of influent chemical oxygen demand was consumed in biomass synthesis. Batch tests showed that the hydrogen-production potential of starch was lower than sucrose, and better conversion efficiency from starch was obtained at a lower pH of 4.5. However, addition of sucrose to starch improved the overall hydrogen-production potential and hydrogen-production rate. This study showed that sustainable biohydrogen production from carbohydrate-rich substrates is possible through heat activation of settled sludge. 相似文献
6.
Saini Y Bhardwaj N Gautam R 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(2):209-212
The paper describes the effect of marble dust on plants in and around Vishwakarma Industrial Area (VKIA) Jaipur, Rajasthan (India). Trees species growing in and around VKIA area were selected and various morphological characteristics were studied such as leaf area dry weight ratio (LADWR), Dust retaining capacity (DRC) and Chlorophyll content. In the study the effects of marble dust on selected tree species was observed. LADWR was recorded maximunm 217.90 cm2 g(-1) dry wt. in Polyalthia longifolia in VKIA and minimum 98.74 cm2 g(-1) dry wt. in Ficus religiosa in Nindar whereas The DRC was observed maximum 178.51 mg cm(-2) in Azadirachta indica in VKIA as well as minimum recorded 66.41 mg cm(-2) in Thevetie pervvianain in Vidyadher Nagar. However the Total Chlorophyll Content was also determined and it was found maximum in Bougainvillea i.e. 2.949 mg g(-1) (fresh wt.) in VKIA whereas minimum for Nindar i.e. 0.784 mg g(-1) (fresh wt.) in Ficus religiosa. 相似文献
7.
Chauhan Anand Sharma Nagendra Kumar Tayal Shilpy Kumar Vimal Kumar Manish 《Journal of Material Cycles and Waste Management》2022,24(5):1797-1817
Journal of Material Cycles and Waste Management - The studies highlightthat only one billion tons were obtained out of four billion tons of solid waste in the world and small value recovered out of... 相似文献
8.
Anaerobically digested swine manure (ADSM) generally contains high concentrations of zinc (Zn) and copper (Cu). These metals levels exceed the land application regulations of municipal biosolids of many European countries and are on the borderline of exceptional quality in the U.S. Environmental Protection Agency (U.S. EPA) 40 CFR part 503 standards. From this perspective, a series of batch tests were conducted to evaluate the feasibility of bioleaching of Zn and Cu from ADSM so that the produced biosolids could safely be applied to land. The effect of different substrate levels (sulfur) and total solids content (as high as 9%) on metal solubilization was investigated. The results showed that metal solubilization efficiency for both Zn and Cu declined significantly with an increase in total solids from 3 to 6% and then to 9% at the same substrate level. Metal solubilization increased proportionately with increases in substrate concentration up to 6% of total solids content. However, at 9% total solids content, metal solubilization was insignificant at all substrate levels tested. At a 6% total solids level and 10 000 mg/L of substrate, 94% of Zn and 72% of Cu were solubilized. Bioleaching was also found to be effective in destruction of pathogens with approximately 2.5 log-scale reduction. The residual biosolid was found to meet the Class A biosolids standands of U.S. EPA 40 CFR part 503. 相似文献
9.
This article analyzes landscape pattern in the WesternGhats mountain ranges in south-western India at two scales,comparing small-scale, detailed studies of landscapepattern, with broader, regional-scale assessments of theWestern Ghats. Due in large part to their inaccessibility,relatively little is known about the landscapes of thisbiodiverse region, which also supports some of the highestpopulation densities in the world. A broad-scale NDVI-basedIRS 1B satellite image classification is used to analyzenorth-south and east-west trends across the entire WesternGhats and western coast of India, an area over 170 000 km2. Northern and eastern landscapes are morefragmented compared to the southern and western slopes.Western slopes also have greater landscape diversity withland cover types more interspersed compared to the easternslopes. These differences can be related to north-south andeast-west variations in rainfall and plant distribution. Data from thirteen landscapes 10–50 km2 in area, arefurther utilized to analyze trends in landscape pattern, anddescribe the geographical distribution of major natural andmanaged ecotope types. At this scale, very high levels ofintra-ecotope type variability in landscape pattern areencountered for all land cover types. Results at these twoscales are integrated to suggest a hierarchical stratifiedapproach for monitoring land cover and biodiversity in the region. 相似文献
10.
Summary This paper compares two forms of public participation in the assessment of appropriate energy technologies: a centralised top- down approach, and an approach based on grass roots empowerment. The example chosen to demonstrate the former is the Community Based Technology Assessment Program in the United States, and examples of the latter are drawn from efforts at assessing biogas technologies in Korea, Thailand and Papua New Guinea. The analysis includes the assessment of each case study in terms of conditions for public participation derived from the literature. Findings point to the need for empowered technology assessment groups and institutional support for program implementation, or "software", for future efforts at diffusing alternative energy technologies to rural settlements in developing countries. In addition, a role for women in technology assessment is recommended.Mr Subbakrishna has been involved with rural development processes in Nigeria, Kenya and India. With a background in the Earth Sciences from the Indian Institute of Technology, Kharagpur, his current specialisation is in natural resource management and energy policy. He is currently engaged in doctoral work at the Energy Center, University of Pennsylvania, USA.Julia Gardner teaches Environmental Management in the School of Community and Regional Planning at the University of British Columbia. She holds a PhD in Geography from the University of Canterbury, New Zealand. Her current research is in the areas of sustainable development and citizen involvement in natural resource management, based at the Westwater Research Center, University of British Columbia. 相似文献