Simulating the fate and transport of TCE from groundwater to indoor air

This work provides an exploratory analysis on the relative importance of various factors controlling the fate and transport of volatile organic contaminants (in this case, TCE) from a DNAPL source zone located below the water table and into the indoor air. The analysis is conducted using the multi-phase compositional model CompFlow Bio, with the base scenario problem geometry reminiscent of a field experiment conducted by Rivett [Rivett, M.O., (1995), Soil–gas signatures from volatile chlorinated solvents: Borden field experiments. Groundwater, 33(1), 84–98.] at the Borden aquifer where groundwater was observed to transport a contaminant plume a substantial distance without vertical mass transport of the contaminant across the capillary fringe and into the vadose zone. Results for the base scenario model indicate that the structure of the permeability field was largely responsible for deflecting the groundwater plume upward towards the capillary fringe, permitting aqueous phase diffusion to transport the TCE into the vadose zone. Alternative permeability realizations, generated as part of a Monte Carlo simulation process, at times deflected the groundwater plume downwards causing the extended thickness of the saturated zone to insulate the vadose zone from exposure to the TCE by upward diffusive transport. Comparison of attenuation coefficients calculated using the CompFlow Bio and Johnson and Ettinger [Johnson, P.C. and Ettinger, R.A., (1991), Heuristic model for predicting the intrusion rate of contaminant vapors into buildings. Environmental Science and Technology, 25, 1445–1452.] heuristic model exhibited fortuitous agreement for the base scenario problem geometry, with this agreement diverging for the alternative permeability realizations as well as when parameters such as the foundation slab fracture aperture, the indoor air pressure drop, the capillary fringe thickness, and the infiltration rate were varied over typical ranges.     

The Cost of Developing Site-Specific Environmental Regulations: Evidence from EPA's Project XL

The flagship of the Environmental Protection Agency's regulatory reinvention initiative, Project XL has been touted as a regulatory blueprint for a site-specific, performance-based pollution-control system, but widespread complaints about the costs of the program beg the question of whether the costs of tailoring regulations to individual facilities are manageable. To address this question, this paper presents original survey data on a sample of 11 XL projects. We find that the fixed costs of putting in place XL agreements are substantial, averaging over $450,000 per firm. While stakeholder negotiations are widely cited as the principal source for these costs, we find that they actually arise mainly from interaction between participating facilities and the EPA. Moreover, EPA management problems are perceived by our survey respondents as having inflated project development costs. Finally, we find that the key factors that explains differences in costs across XL projects are the scope and complexity of the project proposal. These findings suggest that Project XL favors large firms that can afford to pay significant project development costs, that EPA management problems must be resolved to reduce costs, and that there may be a significant economic bias against complex and innovative proposals—precisely the type of proposals that Project XL was designed to foster in order to improve the efficiency of the regulatory system.     

SMART-SREC: A stochastic model of the New Jersey solar renewable energy certificate market

Markets for solar renewable energy certificates (SRECs) are gaining in prominence in many states, stimulating growth of the US solar industry. However, SREC market prices have been extremely volatile, causing high risk to participants and potentially less investment in solar power generation. Such concerns necessitate the development of realistic, flexible and tractable models of SREC prices that capture the behavior of participants given the rules that govern the market. We propose an original stochastic model called SMART-SREC to fill this role, building on established ideas from the carbon pricing literature, and including a feedback mechanism for generation response to prices. We calibrate the model to the New Jersey market and backtest it, analyzing parameter sensitivity and demonstrating its ability to reproduce historical dynamics. Finally, we run simulations to investigate the role and impact of regulatory parameters, thus providing insight into the crucial role played by market design.     

中国法规大气扩散模式及其与其他模式的比较

介绍了中国法规性大气扩散模式(CRADM),分析了CRADM和西方一些模式(如HPDM,AMS)的差别。采用同样条件作为输入,比较并讨论了CRADM,HPDM和AMS在各方面的性能差异。分析了中国大气扩散模式在环境影响评价应用中出现的一些问题,提出了改进建议。特别地,研究表明中性条件下Briggs烟气抬升公式对实际抬升有过高估计,原因是没有考虑环境湍流对烟羽的累积作用      

Multiple receptor ambient monitoring and firm compliance with environmental taxes under budget and target driven regulatory missions

We analyze the potential for an environmental monitoring agency under different regulatory missions to use multiple measures of ambient pollution levels to induce firm compliance via endogenously determined probabilistic firm-level inspections of polluting activities. Departing from previous analyses, we consider a framework where the regulator has multiple, rather than a single, measures of ambient pollution in a setting where many firms are subject to a self-reported emissions tax that is not perfectly enforceable. Under a budget-driven mission, we show that a regulator can fruitfully utilize the added information from multiple ambient monitoring receptors to induce improved environmental compliance through the creation of strategic interactions among firms. Additionally, our results provide new evidence on the relative efficiency of budget- vs. target-driven environmental enforcement missions.     

Environments,Risks, and the Limits of Representation: Examples from Nuclear Energy and Some Implications of Fukushima

This essay examines examples from the field of nuclear energy, including the 2011 disaster at Fukushima-Daiichi, through perspectives drawn from phenomenology, social systems theory, and constitutive communication theory. The essay argues that although prevailing approaches to nuclear risk analysis and risk communication seek to represent a world of preexisting phenomena, they also fundamentally constitute the world on which decision-makers, organizations, and communities act. Representations of nuclear risk are inevitably and problematically limited, with important implications for policy, practice, and communicative action.     

在用机动车尾气排放检测简易瞬态工况法监管策略

针对简易瞬态工况法机动车尾气排放检测过程中层出不穷的违规检测现象,为对其检测过程实施有效监管,通过分析简易瞬态工况法的检测原理,筛选出可用于监管的车辆基准质量、(CO+CO2)浓度、O2浓度、实时检测尾气流量4个参数,分析其用于监管的原理和理由,并通过五气分析仪漏气实验和实测尾气流量异常案例验证其监管可行性,以期为监管...     

Retention time profiling of all 136 tetra- through octa- chlorinated dibenzo-p-dioxins and dibenzofurans on a variety of Si-Arylene gas chromatographic stationary phases

The applicability of three different Silphenylene Silicone co-polymer (Si-Arylene) GC stationary phases (J&W Scientific DB-5ms, Varian VF-5ms, and VF-Xms) has been evaluated for the separation of all 136 tetra- through the octa- chlorinated dibenzo-p-dioxins (PCDD) and chlorinated dibenzofurans (PCDF) from closely eluting isomers using gas chromatography/high resolution mass spectrometry (GC/HRMS). Their relative performance data are compared to the “conventional” 5% diphenyl 95% dimethylpolysiloxane GC column (Supelco Equity-5) and to each other based on absolute retention times, visualized mass chromatograms, and the separation of 2,3,7,8-substituted isomers. VF-Xms GC column was able to demonstrate a better performance towards separation of 2,3,7,8-substituted PCDD/PCDF compared to other Si-Arylene GC columns tested, where only 2,3,4,7,8-PnCDF can not be resolved from 1,2,3,6,9-PnCDF and 2,3,4,6,7,8-/1,2,3,6,8,9-HxCDF and 1,2,3,7,8,9-/1,2,3,4,8,9-HxCDF can be at least partially resolved. These data suggest that the development of a single GC column for the separation of all 17 2,3,7,8-substituted dioxins and furans is feasible, which therefore could be used as a standard tool for the PCDD/PCDF methods globally including USEPA methods 1613b, 8290A, 8280B, European Standard Method EN 1948, Canadian methods DFPCB-E3418, EPS 1/RM/19, Japanese methods JIS K0311 and JIS K0312. Having one specific GC column to separate all 2,3,7,8-substituted PCDD/PCDF will significantly improve the data quality, comparability by the various methods and assessment techniques while simultaneously leading to a more cost and time efficient operation.     

Establishment of permit limits for mill effluent

Various governmental regulatory agencies are responsible for establishing regulations on the discharge of chlorinated organic compounds from pulp and paper mills. The procedures for setting permit limits are the basic topic of this article. Different methods of determining permit limits are set forth and discussed in a number of references, including documents of the Environmental Protection Agency. This paper discusses in detail the application of one particular methodology—the lognormal model approach. In this paper we utilize a real data set and include the necessary calculations required to set up permit limits. The basic tenets of the permit process are such that if limits are set too low, operators who are in full regulatory compliance will still be frequently cited, and if limits are set too high, operators who are not in compliance will seldom if ever be cited. Thus there is a great need for these effluent limits to be determined with great care, both to protect the environment receiving the wastewater and the industry producing the wastewater.