Relationship between Urban and Rural Sulfate Levels

Abstract

The topic of global warming as a result of increased atmospheric CO₂ concentration is arguably the most important environmental issue that the world faces today. It is a global problem that will need to be solved on a global level. The link between anthropogenic emissions of CO₂ with increased atmospheric CO₂ levels and, in turn, with increased global temperatures has been well established and accepted by the world. International organizations such as the United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change (IPCC) have been formed to address this issue. Three options are being explored to stabilize atmospheric levels of greenhouse gases (GHGs) and global temperatures without severely and negatively impacting standard of living: (1) increasing energy efficiency, (2) switching to less carbon-intensive sources of energy, and (3) carbon sequestration. To be successful, all three options must be used in concert. The third option is the subject of this review. Specifically, this review will cover the capture and geologic sequestration of CO₂ generated from large point sources, namely fossil-fuel-fired power gasification plants. Sequestration of CO₂ in geological formations is necessary to meet the President’s Global Climate Change Initiative target of an 18% reduction in GHG intensity by 2012. Further, the best strategy to stabilize the atmospheric concentration of CO₂ results from a multifaceted approach where sequestration of CO₂ into geological formations is combined with increased efficiency in electric power generation and utilization, increased conservation, increased use of lower carbonintensity fuels, and increased use of nuclear energy and renewables.

This review covers the separation and capture of CO₂ from both flue gas and fuel gas using wet scrubbing technologies, dry regenerable sorbents, membranes, cryogenics, pressure and temperature swing adsorption, and other advanced concepts. Existing commercial CO₂ capture facilities at electric power-generating stations based on the use of monoethanolamine are described, as is the Rectisol process used by Dakota Gasification to separate and capture CO₂ from a coal gasifier.

Two technologies for storage of the captured CO₂ are reviewed—sequestration in deep unmineable coalbeds with concomitant recovery of CH4 and sequestration in deep saline aquifers. Key issues for both of these techniques include estimating the potential storage capacity, the storage integrity, and the physical and chemical processes that are initiated by injecting CO₂ underground. Recent studies using computer modeling as well as laboratory and field experimentation are presented here. In addition, several projects have been initiated in which CO₂ is injected into a deep coal seam or saline aquifer. The current status of several such projects is discussed. Included is a commercial-scale project in which a million tons of CO₂ are injected annually into an aquifer under the North Sea in Norway. The review makes the case that this can all be accomplished safely with off-the-shelf technologies. However, substantial research and development must be performed to reduce the cost, decrease the risks, and increase the safety of sequestration technologies.

This review also includes discussion of possible problems related to deep injection of CO₂ . There are safety concerns that need to be addressed because of the possibilities of leakage to the surface and induced seismic activity. These issues are presented along with a case study of a similar incident in the past. It is clear that monitoring and verification of storage will be a crucial part of all geological sequestration practices so that such problems may be avoided. Available techniques include direct measurement of CO₂ and CH4 surface soil fluxes, the use of chemical tracers, and underground 4-D seismic monitoring.

Ten new hypotheses were formulated to describe what happens when CO₂ is pumped into a coal seam. These hypotheses provide significant insight into the fundamental chemical, physical, and thermodynamic phenomena that occur during coal seam sequestration of CO₂ .     

Evaluation of Selected Gaseous Halocarbons for Use in source Test Performance Audits

A repository of 38 gaseous organic compounds in compressed gas cylinders has been established by EPA. This repository was established to provide standards for source test performance audits, that is, quantitative quality assurance tests. Among these compounds are ten halogenated organic species, which are the focus of this paper.

Stability studies of all ten compounds have been performed to determine the feasibility of using them as performance audit standards. Results indicate that all of the halocarbons tested are adequately stable to be used as reliable audit standards.

Subsequent to completion of stability studies, four of the ten halocarbons were used in source test performance audits. Results are available at this time for two of the four compounds; the results show agreement within 10% of the concentrations previously established by Research Triangle Institute.     

Quantification and analysis of airborne bacterial characteristics in a nursing care institution

Indoor air quality has become a critical issue because people spend most of their time in the indoor environment. The factors that influence indoor air quality are very important to environmental sanitation and air quality improvement. This study focuses on monitoring air quality, colony counts, and bacteria species of the indoor air of a nursing care institution. The regular colony counts in two different wards range from 55 to 600 cfu m(-3) Regression analysis results indicate that the bacterial colony counts have close correlation with relative humidity or carbon dioxide (CO2) but not with carbon monoxide (CO) or ozone (O3). Real-time PCR was used to quantify the bacterial pathogens of nosocomial infection, including Acinetobacter baumannii, Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, and methicillin-sensitive Staphylococcus aureus. The most abundant bacteria species in the air of the nursing care institution is E. coli.     

煤气废水中有机化合物的生物去除特征

好氧/缺氧/好氧生物处理系统是一种新型煤气废水二级处理工艺,该工艺通过改变微生物的生化环境,充分发挥各单元对有机化合物的降解功能,强化了有机化合物总体去除效果.主要采用气相色谱/质谱联用(GC/MS)测试方法,分析对比煤气废水进水及其系统各单元出水中有机化合物的成分,结合生物降解的特点,评价各单元对有机化合物的去除效果...     

羟基磷灰石的制备及其对水中氟离子的吸附

本研究利用红外光谱(FTIR)、扫描电镜(SEM)和X射线粉末衍射(XRD)观察了共沉淀法合成羟基磷灰石(HAP)的形貌及其晶型结构,并探讨了Ca/P摩尔比、反应时间及反应温度等因素对羟基磷灰石吸附水中氟离子性能的影响。结果表明,n(Ca/P)=1.5/1、反应时间1 h、反应温度40℃、陈化时间48 h、煅烧温度200℃、煅烧时间2 h时,HAP除氟效果最佳,吸附效率和吸附容量分别达到68.8%和6.88 mg/g。实验数据Langmuir等温模式拟合效果优于Freundlich模式,热力学参数计算可知,HAP对氟离子的吸附是自发(ΔG00),吸热(ΔH00),熵增(ΔS00)的过程。HAP对氟离子的吸附符合拟二级反应动力学过程。     

A new approach to quantify the degradation kinetics of linuron with UV, ozonation and UV/O3 processes

The degradation of linuron, one of phenylurea herbicides, was investigated for its reaction kinetics by different treatment processes including ultraviolet irradiation (UV), ozonation (O₃), and UV/O₃. The decay rate of linuron by UV/O₃ process was found to be around 3.5 times and 2.5 times faster than sole-UV and ozone-alone, respectively. Experimental results also indicate overall rate constants increased exponentially with pH above 9.0 while the increase of rate constants with pH below 9 is insignificant in O₃ system. All dominant parameters involved in the three processes were determined in the assistant of proposed linear models in this study. The approach was found useful in predicting the process performances through the quantification of quantum yield (rate constant for the formation of free radical HOO⁻ from ozone decomposition at high pH), rate constant of linuron with ozone (k_O3,LNR), rate constant of linuron with hydroxyl radical (k_OH,LNR), and α (the ratio of the production rate of OH and the decay rate of ozone in UV/O₃ system).     

An observational study of the HONO–NO2 coupling at an urban site in Guangzhou City,South China

The temporal behavior of HONO and NO₂ was investigated at an urban site in Guangzhou city, China, by means of a DOAS system during the Pearl River Delta 2006 intensive campaign from 10 to 24 July 2006. Within the whole measurement period, unexpected high HONO mixing ratios up to 2 ppb were observed even during the day. A nocturnal maximum concentration of about 8.43 ± 0.4 ppb was detected on the night of 24 July 2006. Combining the data simultaneously observed by different instruments, the coupling of HONO–NO₂ and the possible formation sources of HONO are discussed. During the measurement period, concentration ratios of HONO to NO₂ ranged from (0.03 ± 0.1) to (0.37 ± 0.09), which is significantly higher than previously reported values (0.01–0.1). Surprisingly, in most cases a strong daytime correlation between HONO and NO₂ was found, contrary to previous observations in China. Aerosol was found to have a minor impact on HONO formation during the whole measurement period. Using a pseudo steady state approach for interpreting the nocturnal conversion of NO₂ to HONO suggests a non-negligible role of the relative humidity for the heterogeneous HONO formation from NO₂.     

Predicted concentrations of biocides from antifouling paints in Visakhapatnam Harbour

The concentrations of biocides leached from antifouling coatings are monitored in most of the developed countries. However, in India and many other developing countries, there is very little data available on the concentrations of biocides in ports and harbours. The first step was to obtain the order of magnitude levels of concentrations of biocides in the marine environment of the Visakhapatnam Harbour, and the MAM-PEC (Marine Antifoulant Model to Predict Environmental Concentrations) model was used to predict these values. The Visakhapatnam Port lies on the eastern coast of India, roughly halfway between Chennai and Kolkata, and is the largest port in India. This port is a natural harbour; the long and narrow outlet to the open sea makes it a 'poorly flushed' harbour. Predicted concentrations of tributyltin (TBT), copper, dichlofluanid, seanine, irgarol, diuron, tolylfluanid, and zinc pyrithione were computed. The results of the computations indicate that the levels of these biocides are comparable to those in many western countries. This gives credence to the fact that persistence of TBT and some other biocides is a global problem that cannot be ignored.     

Physico-Chemical Quality of Drinking Water in Rohtas District of Bihar

Water Quality Survey of Rohtas district of Bihar was conducted. Samples were collected from differentsources and analysed. 209 samples were collectedfrom 196 villages. Results of water quality surveyidentified the problem areas in respect of high iron,manganese, fluoride, nitrate and brackishness of water in the district.     

Measurement of particulate phase polycyclic aromatic hydrocarbon (PAHs) around a petroleum refinery

A study on concentrations of ambient particulates viz. total suspended particulate matters (TSP), respirable suspended particulate matter (RSPM) and polycyclic aromatic hydrocarbons (PAH) were carried out at six sites around the Asia’s largest, 12 MMTPA, petroleum refinery in west coast of India. PAH concentrations are correlated with each other in these sites, suggesting that they have related sources and sinks. The present article discusses the monitoring aspects such as sample collection, pretreatment and analytical methods and compares the monitored levels for assessing the source receptor distribution pattern. The main sources of RSPM and PAHs in urban air are automobile exhaust (CPCB, Polycyclic aromatic hydrocarbons (PAHs) in air and their effects on human health. “”, 2003; Manuel et al., Environmental Science and Technology, 13: 227–231, 2004) and industrial emissions like petroleum refinery (Vo-Dinh, Chemical analysis of polycyclic aromatic hydrocarbons, Wiley: New York, 1989; Wagrowaski and Hites, Environmental Science and Technology, 31: 279–282, 1997). Polycyclic aromatic hydrocarbons (PAH) are ubiquitous constituents of urban airborne particulate mostly generated by anthropogenic activities (Li et al., Environmental Science and Technology, 37:1958–2965, 2003; Thorsen et al., Environmental Science and Technology, 38: 2029–2037, 2004; Ohura et al., Environmental Science and Technology, 32: 450–455, 2004) and some of them are of major health concern mainly due to their well-known carcinogenic and mutagenic properties (Soclo et al., Marine Pollution Bulletin, 40: 387–396, 2000; Chen et al., Environment International, 28: 659–668, 2003; Larsen and Baker, Environmental Science and Technology, 32: 450–455, 2003). Limited information is available on PAHs contributions from refineries to ambient air. Hence this study would not only create a database but also provide necessary inputs towards dose-response relationship for fixing standards. Also, since it acts as precursor to green house gas, the data would be useful for climate change assessments. The objective of this article is to find out the concentration of PAHs in particulate matter around petroleum refinery and compare with their concentrations in major Indian urban centers.