The sensitivity of modeled ozone to the temporal distribution of point, area, and mobile source emissions in the eastern United States

Ozone remains one of the most recalcitrant air pollution problems in the US. Hourly emissions fields used in air quality models (AQMs) generally show less temporal variability than corresponding measurements from continuous emissions monitors (CEM) and field campaigns would imply. If emissions control scenarios to reduce emissions at peak ozone forming hours are to be assessed with AQMs, the effect of emissions' daily variability on modeled ozone must be understood. We analyzed the effects of altering all anthropogenic emissions' temporal distributions by source group on 2002 summer-long simulations of ozone using the Community Multiscale Air Quality Model (CMAQ) v4.5 and the Carbon Bond IV (CBIV) chemical mechanism with 12 km resolution. We find that when mobile source emissions were made constant over the course of a day, 8-h maximum ozone predictions changed by ±7 parts per billion by volume (ppbv) in many urban areas on days when ozone concentrations greater than 80 ppbv were simulated in the base case. Increasing the temporal variation of point sources resulted in ozone changes of +6 and −6 ppbv, but only for small areas near sources. Changing the daily cycle of mobile source emissions produces substantial changes in simulated ozone, especially in urban areas at night; results suggest that shifting the emissions of NO_x from day to night, for example in electric powered vehicles recharged at night, could have beneficial impacts on air quality.     

我国排污权交易制度的相关问题探析

随着经济的快速发展,工业生产中排放的废弃物越来越多,由此造成的环境压力也越来越大,随着可持续发展概念的不断提出,排污权交易制度也被逐渐确定下来,该制度在我国的施行不但具有可行性,更加具有必要性。本文对我国当前排污权制度实施的不足之处进行了详细分析,并提出了我国排污权制度未来的完善路径。     

Dispersion modeling approach for quantification of methane emission rates from natural gas fugitive leaks detected by infrared imaging technique

Recently, infrared optical imaging has been applied in the oil and gas industry as a method to detect potential leaks in pipelines, components and equipment. The EPA suggested that this impending technique is considered as a smart gas LDAR (leak detection, monitoring and repair) for its rapid recognition of leaks, accuracy and robustness. In addition, compared to the conventional method using Total Vapor Analyzer (TVA) or gas sniffer, it has several other advantages, such as the ability to perform real-time scanning and remote sensing, ability to provide area measurement instead of point measurement, and provide an image of the gas which is not visible to naked eye. However, there is still some limitation in the application of optical imaging techniques; it does not give any measurement of gas emissions rates or concentrations of the leaking gas. Infrared cameras can recognize a target gas and distinguish the gas from its surrounding up to a certain concentration, namely the minimum detectable concentration. The value of the minimum detectable concentration depends on the camera design, environmental conditions and surface characteristics when the measurement is taken. This paper proposed a methodology to predict gas emissions rates from the size of the dispersed gas plume or cloud to the minimum detectable concentration. The gas emissions rate is predicted from the downwind distance and the height of the cloud at the minimum detectable concentration for different meteorological conditions. Gas release and dispersion from leaks in natural gas pipeline systems is simulated, and the results are presented.     

“I Drink It Anyway and I Know I Shouldn't”: Understanding Green Consumers' Positive Evaluations of Norm-violating Non-green Products and Misleading Green Advertising

Individual and collective efforts to mitigate climate change in the form of carbon offsetting and emissions trading schemes have recently become the focus of much media attention. In this paper we explore a subset of the UK national press coverage centered on such schemes. The articles, selected from general as well as specialized business and finance newspapers, make use of gold rush, Wild West, and cowboy imagery which is rooted in deeply entrenched myths and metaphors and allows readers to make sense of very complex environmental, political, ethical, and financial issues associated with carbon mitigation. They make what appears complicated and unfamiliar, namely carbon trading and offsetting, seem less complex and more familiar. A critical discussion of this type of imagery is necessary in order to uncover and question tacit assumptions and connotations which are built into it and which might otherwise go unnoticed and unchallenged in environmental communication.     

Pollution characteristics of particulate matters emitted from outdoor barbecue cooking in urban Jinan in eastern China

To understand the pollution characteristics of particulate matter emitted from outdoor barbecue cooking in eastern China, measurements of the PM_2.5 mass concentration, the number concentration of particles with a diameter of 0.01 to 1.0 μm, and the particle size distribution from 0.3 to 25 μm were carried out at seven barbecue restaurants in urban Jinan. The average PM_2.5 mass concentration and sub-micron particle number concentrations at a distance of 1 m from the grills were 250 to 1083 μg/m³ and 0.90 × 10⁵ to 2.23 × 10⁵ cm^–3, respectively, which were much higher than those in the ambient air of the urban area. Compared to the ambient atmosphere, barbecue cooking emitted very high levels of particles with a larger increase in the concentrations of super-micron particles than that of sub-micron particles. The super-micron particle number concentrations at the barbecue restaurants were 10 to 100 times higher than those observed in the ambient urban atmosphere. The barbecue smoke had a significant effect on the particle concentrations in the surrounding region. Both mass and number concentrations of particles exhibited maximum values immediately near the barbecue grills and often reached a peak at a distance of 10 to 15 m. The removal efficiency of a range hood for the cooking particles was tested in an indoor kitchen. The range hood effectively cleaned the particulate matter pollution caused by cooking with a removal efficiency larger than 80%. Therefore, the use of a range hood is recommended for outdoor barbecue restaurants coupled with a smoke purifier to clean the emitted high concentrations of particles.

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Endosulfan in China 2—emissions and residues

Background, aim, and scope  Endosulfan is one of the organochlorine pesticides (OCPs) and also a candidate to be included in a group of new persistent organic pollutants (UNEP 2007). The first national endosulfan usage inventories in China with 1/4° longitude by 1/6° latitude resolution has been reported in an accompanying paper. In the second part of the paper, we compiled the gridded historical emissions and soil residues of endosulfan in China from the usage inventories. Based on the residue/emission data, gridded concentrations of endosulfan in Chinese soil and air have been calculated. These inventories will provide valuable data for the further study of endosulfan. Methods  Emission and residue of endosulfan were calculated from endosulfan usage by using a simplified gridded pesticide emission and residue model—SGPERM, which is an integrated modeling system combining mathematical model, database management system, and geographic information system. By using the emission and residue inventories, annual air and soil concentrations of endosulfan in each cell were determined. Results and discussion  Historical gridded emission and residue inventories of α- and β-endosulfan in agricultural soil in China with 1/4° longitude by 1/6° latitude resolution have been created. Total emissions were around 10,800 t, with α-endosulfan at 7,400 t and β-endosulfan at 3,400 t from 1994 to 2004. The highest residues were 140 t for α-endosulfan and 390 t for β-endosulfan, and the lowest residues were 0.7 t for α-endosulfan and 170 t for β-endosulfan in 2004 in Chinese agricultural soil where endosulfan was applied. Based on the emission and residue inventories, concentrations of α- and β-endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell. We have estimated annual averaged air concentrations and the annual minimum and maximum soil concentrations across China. The real concentrations will be different from season to season. Although our model does not consider the transport of the insecticide in the atmosphere, which could be very important in some areas during some special time, the estimated concentrations of endosulfan in Chinese air and soil derived from the endosulfan emission and residue inventories are in general consistent with the published monitoring data. Conclusions  To our knowledge, this work is the first inventory of this kind for endosulfan published on a national scale. Concentrations of the chemical in Chinese air and agricultural surface soil were calculated for each grid cell. Results show that the estimated concentrations of endosulfan in Chinese air and soil agree reasonably well with the monitoring data in general. Recommendations and perspectives  The gridded endosulfan emission/residue inventories and also the air and soil concentration inventories created in this study will be updated upon availability of new information, including usage and monitoring data. The establishment of these inventories for the OCP is important for both scientific communities and policy makers.     

WATER-ENERGY LINKAGES IN NEBRASKA1

ABSTRACT Nebraska is well endowed with water, particularly groundwater, but has few fossil fuel reserves. However, it is located adjacent to states which have almost no water but have enormous quantities of coal and oil shale. Recent court cases facilitate the movement of water from water-rich states such as Nebraska to water-short states, such as Colorado and Wyoming. The possibility of an energy-water partnership exists and raise numerous policy questions. Within Nebraska, energy consumption patterns are similar to those of the nation's, with consumption of electricity in the agricultural sector growing fastest. Water consumption in the state is dominated by agriculture, and future development of groundwater for irrigation is expected to be intense. Although water and energy are both factors of economic production, an equivalent amount of water consumption provides more jobs in the energy industries than in agriculture. Water and energy are also interdependent. Each is required to produce the other and conservation of one will cause conservation of the other. If both agriculture and electricity are involved, such as in irrigation, the conservation effects are synergistic. Current water policy in Nebraska is biased toward agriculture relative to the energy industries and provides little incentive for water conservation. Given recent court cases and economic conditions, the advantages and disadvantages of the sale of water for export or the use of water with Wyoming coal for energy development need to be compared systematically with those of using water only for agriculture.     

IMPROVING WATER RESOURCE ALLOCATION THROUGH DEMAND-ORIENTED WATER POLICY1

ABSTRACT. In the arid and semi-arid regions of the Western United States the water problem is generally perceived as one of “inadequate” supply. This conception of the problem engenders supply-oriented water policy, or policy focusing exclusively upon a single class of solutions–the various schemes for augmenting an area's water supply. In a more complete or balanced conceptualization, the water problem is viewed as one of “inadequate” supply and/or “excessive” demand. When the water problem is so conceived, water policy is broadened to include demand-oriented water policy, or policy aimed at reducing the quantity of water demanded in an area. The purpose of this paper is to describe and explain demand-oriented water policy. Basically it consists of changing the set of commodities produced by the economy, cutting back and/or eliminating goods requiring large quantities of water in their production and introducing and/or expanding goods which require little water. This paper also reports briefly on research undertaken to test demand-oriented policy in Arizona. Results indicate that such a policy can be extremely efficacious in solving a region's water problem.     

Characterization and source analysis of indoor/outdoor culturable airborne bacteria in a municipal wastewater treatment plant

The potential health risks of airborne bacteria emission from a wastewater treatment process have been concerned. However, few studies have investigated the differences in community structure between indoor and outdoor bacteria. In this work, the characterization of airborne bacteria was studied in a municipal wastewater treatment plant in Beijing, China. Two indoor (i.e., fine screen room and sludge dewatering house) and two outdoor (i.e., aeration tank and control site) sampling sites were selected. An Andersen six-stage impactor was used for collecting culturable airborne bacteria in the air, and Illumina MiSeq sequencing was conducted to track the emission source of the culturable airborne bacteria. The results indicate that, compared with the outdoor aeration tank site, the concentrations of culturable airborne bacteria in the indoor fine screen room with poor ventilation were more than ten times higher and the particle size was about twice as large. The community structures of indoor and outdoor culturable airborne bacteria were obviously different. Enterobacteriaceae and opportunistic pathogens were detected in indoor culturable airborne bacteria, with wastewater and sludge dewatering machine identified as the primary sources. Conversely, Enterobacteriaceae and opportunistic pathogens were not detected in outdoor culturable airborne bacteria. Outdoor high wind speed might have resulted in rapid dilution and mixing of culturable airborne bacteria generated from the aeration tank with the ambient air. The results of the present research suggest that covering pollution sources, increasing ventilation rates, and using protective measures for personnel should be implemented to decrease the exposure risk to indoor culturable airborne bacteria.     

2005～2009年南京市二氧化碳排放特征研究

采用IPCC报告(2006版)提供的计量方法与碳含量缺省值,对南京市能源消费碳排放进行了计量研究.结果表明:从2005～2009年,CO2排放总量从8.05×107t增加到1.02×108t,人均CO2排放量从11.7 t/a增加到13.2 t/a,但CO2排放强度持续降低,从3.34 t/万元下降到2.41 t/万元...