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Accuracy Of Three Screening Level Vapor Intrusion Models For Indoor Air
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Book Synopsis Accuracy of Three Screening-level Vapor Intrusion Models for Indoor Air by :
Download or read book Accuracy of Three Screening-level Vapor Intrusion Models for Indoor Air written by and published by . This book was released on 2016 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vapor intrusion models were developed to predict indoor air concentrations from subsurface sources and then calculate an associated risk using toxicological data and exposure scenarios for the building occupants. Prior to the issuance of final guidance documents in 2015, the United States Environmental Protection Agency (USEPA) guidance on vapor intrusion was in draft form since November 2002. This delay between the draft version and the final guidelines resulted in the utilization of varying methodologies for assessing vapor intrusion by the regulated community and as well as the regulators at both state and local levels. The purpose of this study was to evaluate the accuracy of screening-level vapor intrusion models, using soil vapor samples collected from three sites with known or suspected contamination, and to compare the predicted indoor air results with measured indoor air results. The models evaluated were the County of San Diego Department of Environmental Health Vapor Risk 2000 Model, the Department of Toxic Substances Control (DTSC) version of the Johnson and Ettinger Model (J&E Model), and the USEPA, Office of Solid Waste and Emergency Response (OSWER), Vapor Intrusion Screening Level Calculator (VISLC). The results of this study found that the Vapor Risk 2000 Model more accurately predicts indoor air concentrations, followed by the J&E Model and VISLC. While the Vapor Risk 2000 Model more closely predicts the indoor air concentration, it does have a tendency to underpredict. Due to the underpredictions, there is more potential for false negatives (i.e., screening out sites that do have a potential for vapor intrusion. Similar to previous studies, this study found the Vapor Risk 2000 and J&E Models both over and under predict the indoor air concentrations. This may not necessarily be a reflection on the model’s prediction ability, but rather the complexity of vapor intrusion and the confounders of indoor air. Combined with additional lines of evidence (e.g., indoor air sampling), these screening-level vapor intrusion models can assist decision makers in screening in or out sites that are susceptible to vapor intrusion.
Book Synopsis Vapor Intrusion Simulations and Risk Assessments by : Yijun Yao
Download or read book Vapor Intrusion Simulations and Risk Assessments written by Yijun Yao and published by Springer Nature. This book was released on 2022-07-25 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces key concepts in modeling and risk assessments of vapor intrusion, a process by which the subsurface volatile contaminants migrate into the building of concern. Soil vapor intrusion is the major exposure pathway for building occupants to chemicals from the subsurface, and its risk assessments determine the criteria of volatile contaminants in soil/groundwater in brownfield redevelopment. The chapters feature the recent advances in vapor intrusion studies and practices, including analytical and numerical modeling of vapor intrusion, statistical findings of United States Environmental Protection Agency’s Vapor Intrusion Database and Petroleum Vapor Intrusion Databases, the challenges of preferential pathways, and the application of building pressure cycling methods, and field practices of vapor intrusion risk assessments at developed contaminated sites and in brownfield redevelopment. This volume also summarizes the advantages and limits of current applications in vapor intrusion risk assessment, laying the groundwork for future research of better understanding in risk characterization of soil vapor intrusion using models. Written by experts in this field, Vapor Intrusion Simulations and Risk Assessments will serve as an invaluable reference for researchers, regulators, and practitioners, who are interested in perceiving the basic knowledge and current advances in risk assessments of soil vapor intrusion.
Book Synopsis Vapor Intrusion Modeling by : Jessica Marie Friscia
Download or read book Vapor Intrusion Modeling written by Jessica Marie Friscia and published by . This book was released on 2014 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vapor intrusion is the migration of volatile organic compounds (VOCs) from a subsurface source into the indoor air of an overlying building. Vapor intrusion models, including the Johnson and Ettinger (J&E) model, can be used to predict the concentration of VOCs in the indoor air of a building based on a measured subsurface soil gas concentration or contaminant source concentrations, either in non-aqueous phase liquid (NAPL), groundwater, or soil. An analysis of two of the EPA-implemented J&E spreadsheet models, one that considers subsurface soil gas data and one that considers groundwater data, was conducted. The governing equations, assumptions, and limitations of these spreadsheet models were investigated. A value of information (Vol) worksheet was developed that can assist practitioners in deciding what additional data to collect as part of a remedial investigation. The Vol worksheet calculates how varying values of model input parameters affect the model-predicted indoor air carcinogenic risk. The worksheet then compares the user-defined target risk to the range of potential risk values for different combinations of varying parameters. The results of this analysis allow the user to determine which groups of parameters have the most impact on the model results. This information can assist the practitioner in deciding whether or not to collect additional data to reduce the uncertainty in the input parameters. The EPA J&E soil gas and groundwater spreadsheet models, as well as the Vol worksheet developed for each model, were applied to case study data for a trichloroethylene-impacted site in Rhode Island. The results of the J&E model and Vol worksheet analyses for this case study predicted incremental carcinogenic risk values for trichloroethylene (TCE) below the risk value calculated based on measured indoor air data. This comparison suggests the potential for other sources of TCE within the building. Groups of parameters were identified for each model that impacted the model-predicted carcinogenic risk. The development of a cost-benefit analysis, which would be used to quantify the value of obtaining additional data for these critical parameters, is recommended for future research.
Download or read book Soil Screening Guidance written by and published by . This book was released on 1996 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis WHO Guidelines for Indoor Air Quality by :
Download or read book WHO Guidelines for Indoor Air Quality written by and published by World Health Organization. This book was released on 2010 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents WHO guidelines for the protection of public health from risks due to a number of chemicals commonly present in indoor air. The substances considered in this review, i.e. benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons (especially benzo[a]pyrene), radon, trichloroethylene and tetrachloroethylene, have indoor sources, are known in respect of their hazardousness to health and are often found indoors in concentrations of health concern. The guidelines are targeted at public health professionals involved in preventing health risks of environmental exposures, as well as specialists and authorities involved in the design and use of buildings, indoor materials and products. They provide a scientific basis for legally enforceable standards.
Book Synopsis Evaluation of Vapor Intrusion Pathway Assessment Through Long-term Monitoring Studies by : Chase Weston Holton
Download or read book Evaluation of Vapor Intrusion Pathway Assessment Through Long-term Monitoring Studies written by Chase Weston Holton and published by . This book was released on 2015 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vapor intrusion (VI) pathway assessment often involves the collection and analysis of groundwater, soil gas, and indoor air data. There is temporal variability in these data, but little is understood about the characteristics of that variability and how it influences pathway assessment decision-making. This research included the first-ever collection of a long-term high-frequency indoor air data set at a house with VI impacts overlying a dilute chlorinated solvent groundwater plume. It also included periodic synoptic snapshots of groundwater and soil gas data and high-frequency monitoring of building conditions and environmental factors. Indoor air trichloroethylene (TCE) concentrations varied over three orders-of-magnitude under natural conditions, with the highest daily VI activity during fall, winter, and spring months. These data were used to simulate outcomes from common sampling strategies, with the result being that there was a high probability (up to 100%) of false-negative decisions and poor characterization of long-term exposure. Temporal and spatial variability in subsurface data were shown to increase as the sampling point moves from source depth to ground surface, with variability of an order-of-magnitude or more for sub-slab soil gas. It was observed that indoor vapor sources can cause subsurface vapor clouds and that it can take days to weeks for soil gas plumes created by indoor sources to dissipate following indoor source removal. A long-term controlled pressure method (CPM) test was conducted to assess its utility as an alternate approach for VI pathway assessment. Indoor air concentrations were similar to maximum concentrations under natural conditions (9.3 [micro]g/m3 average vs. 13 [micro]g/m3 for 24 h TCE data) with little temporal variability. A key outcome was that there were no occurrences of false-negative results. Results suggest that CPM tests can produce worst-case exposure conditions at any time of the year. The results of these studies highlight the limitations of current VI pathway assessment approaches and demonstrate the need for robust alternate diagnostic tools, such as CPM, that lead to greater confidence in data interpretation and decision-making.
Book Synopsis Application of Risk-based Screening Levels and Decision Making to Sites with Impacted Soil and Groundwater: Background documentation for the development of Tier 1 soil and groundwater screening levels by :
Download or read book Application of Risk-based Screening Levels and Decision Making to Sites with Impacted Soil and Groundwater: Background documentation for the development of Tier 1 soil and groundwater screening levels written by and published by . This book was released on 2001 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Health Effects Assessment Summary Tables by :
Download or read book Health Effects Assessment Summary Tables written by and published by . This book was released on 1997 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modelling of Pollutants in Complex Environmental Systems by : Grady Hanrahan
Download or read book Modelling of Pollutants in Complex Environmental Systems written by Grady Hanrahan and published by ILM Publications. This book was released on 2010 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental modelling has enjoyed a long tradition, but there is a defined need to continually address both the power and the limitations of such models, as well as their quantitative assessment. This book showcases modern environmental modelling methods, the basic theory behind them and their incorporation into complex environmental investigations. It highlights advanced computing technologies and how they have led to unprecedented and adaptive modelling, simulation and decision-support tools to study complex environmental systems, and how they can be applied to current environmental concerns. This volume is essential reading for researchers in academia, industry and government-related bodies who have a vested interest in all aspects of environmental modelling. Features include: A range of modern environmental modelling techniques are described by experts from around the world, including the USA, Canada, Australia, Europe and Thailand; many examples from air, water, soil/sediment and biological matrices are covered in detail throughout the book; key chapters are included on modelling uncertainty and sensitivity analysis; and, a selection of figures are provided in full colour to enable greater comprehension of the topics discussed.
Book Synopsis Dealing with Contaminated Sites by : Frank A. Swartjes
Download or read book Dealing with Contaminated Sites written by Frank A. Swartjes and published by Springer Science & Business Media. This book was released on 2011-01-12 with total page 1121 pages. Available in PDF, EPUB and Kindle. Book excerpt: This standard work on contaminated site management covers the whole chain of steps involved in dealing with contaminated sites, from site investigation to remediation. An important focus throughout the book is on Risk Assessment. In addition, the book includes chapters on characterisation of natural and urban soils, bioavailability, natural attenuation, policy and stakeholder viewpoints and Brownfields. Typically, the book includes in-depth theories on soil contamination, along with offering possibilities for practical applications. More than sixty of the world’s top experts from Europe, the USA, Australia and Canada have contributed to this book. The twenty-five chapters in this book offer relevant information for experienced scientists, students, consultants and regulators, as well as for ‘new players’ in contaminated site management
Book Synopsis Natural Attenuation of Fuels and Chlorinated Solvents in the Subsurface by : Todd H. Wiedemeier
Download or read book Natural Attenuation of Fuels and Chlorinated Solvents in the Subsurface written by Todd H. Wiedemeier and published by John Wiley & Sons. This book was released on 1999-03-08 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive guide to one of today's most innovative approaches to environmental contamination Natural attenuation is gaining increasing attention as a nonintrusive, cost-effective alternative to standard remediation techniques for environmental contamination. This landmark work presents the first in-depth examination of the theory, mechanisms, and application of natural attenuation. Written by four internationally recognized leaders in this approach, the book describes both biotic and abiotic natural attenuation processes, focusing on two of the environmental contaminants most frequently encountered in groundwater--fuels and chlorinated solvents. The authors draw on a wealth of combined experience to detail successful techniques for simulating natural attenuation processes and predicting their effectiveness in the field. They also show how natural attenuation works in the real world, using numerous examples and case studies from a wide range of leading-edge projects nationwide involving fuel hydrocarbons and chlorinated solvents. Finally, they discuss the evaluation and assessment of natural attenuation and explore the design of long-term monitoring programs. An indispensable reference for anyone working in environmental remediation, Natural Attenuation of Fuels and Chlorinated Solvents in the Subsurface is essential reading for scientists and engineers in a range of industries, as well as state and federal environmental regulators, and professors and graduate students in environmental or chemical engineering.
Book Synopsis Demonstration and Validation of the Use of Passive Samplers for Monitoring Soil Vapor Intrusion to Indoor Air by : Todd Arthur McAlary
Download or read book Demonstration and Validation of the Use of Passive Samplers for Monitoring Soil Vapor Intrusion to Indoor Air written by Todd Arthur McAlary and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis documents a demonstration/validation of passive diffusive samplers for assessing soil vapor, indoor air and outdoor air concentrations of volatile organic compounds (VOCs) at sites with potential human health risks attributable to subsurface vapor intrusion to indoor air. The study was funded by the United States (U.S.) Department of Defense (DoD) and the U.S. Department of the Navy (DoN). The passive samplers tested included: SKC Ultra and Ultra II, Radiello®, Waterloo Membrane Sampler (WMS), Automated Thermal Desorption (ATD) tubes, and 3M OVM 3500. The program included laboratory testing under controlled conditions for 10 VOCs (including chlorinated ethenes, ethanes, and methanes, as well as aromatic and aliphatic hydrocarbons), spanning a range of properties and including some compounds expected to pose challenges (naphthalene, methyl ethyl ketone). Laboratory tests were performed under conditions of different temperature (17 to 30 oC), relative humidity (30 to 90 % RH), face velocity (0.014 to 0.41 m/s), concentration (1 to 100 parts per billion by volume [ppbv]) and sample duration (1 to 7 days). These conditions were selected to challenge the samplers across a range of conditions likely to be encountered in indoor and outdoor air field sampling programs. A second set of laboratory tests were also conducted at 1, 10 and 100 parts per million by volume (ppmv) to evaluate concentrations of interest for soil vapor monitoring using the same 10 VOCs and constant conditions (80% RH, 30 min exposure, 22 oC). Inter-laboratory testing was performed to assess the variability attributable to the differences between several laboratories used in this study. The program also included field testing of indoor air, outdoor air, sub-slab vapor and deeper soil vapor at several DoD facilities. Indoor and outdoor air samples were collected over durations of 3 to 7 days, and Summa canister samples were collected over the same durations as the passive samples for comparison. Subslab and soil vapor samples were collected with durations ranging from 10 min to 12 days, at depths of about 15 cm (immediately below floor slabs), 1.2 m and 3.7 m. Passive samplers were employed with uptake rates ranging from about 0.05 to almost 100 mL/min and analysis by both thermal desorption and solvent extraction. Mathematical modeling was performed to provide theoretical insight into the potential behavior of passive samplers in the subsurface, and to help select those with uptake rates that would minimize the risk of a negative bias from the starvation effect (which occurs when a passive sampler with a high uptake rate removes VOC vapors from the surroundings faster than they are replenished, resulting in biased concentrations). A flow-through cell apparatus was tested as an option for sampling existing sub-surface probes that are too small to accommodate a passive sampler or sampling a slip-stream of a high-velocity gas (e.g., vent-pipes of mitigation systems). The results of this demonstration show that all of the passive samplers provided data that met the performance criteria for accuracy and precision (relative percent difference less than 45 % for indoor air or 50% for soil vapor compared to conventional active samples and a coefficient of variation less than 30%) under some or most conditions. Exceptions were generally attributable to one or more of five possible causes: poor retention of analytes by the sorbent in the sampler; poor recovery of the analytes from the sorbent; starvation effects, uncertainty in the uptake rate for the specific combination of sampler/compound/conditions, or blank contamination. High (or positive) biases were less common than low biases, and attributed either to blank contamination, or to uncertainty in the uptake rates. Most of the passive samplers provided highly reproducible results throughout the demonstrations. This is encouraging because the accuracy can be established using occasional inter-method verification samples (e.g., conventional samples collected beside the passive samples for the same duration), and the field-calibrated uptake rates will be appropriate for other passive samples collected under similar conditions. Furthermore, this research demonstrated for the first time that passive samplers can be used to quantify soil vapor concentrations with accuracy and precision comparable to conventional methods. Passive samplers are generally easier to use than conventional methods (Summa canisters and active ATD tubes) and minimal training is required for most applications. A modest increase in effort is needed to select the appropriate sampler, sorbent and sample duration for the site-specific chemicals of concern and desired reporting limits compared to Summa canisters and EPA Method TO-15. As the number of samples in a given program increases, the initial cost of sampling design becomes a smaller fraction of the overall total cost, and the passive samplers gain a significant cost advantage because of the simplicity of the sampling protocols and reduced shipping charges.
Book Synopsis Guidelines For Monitoring Indoor Air Quality by : Niren Laxmichand Nagda
Download or read book Guidelines For Monitoring Indoor Air Quality written by Niren Laxmichand Nagda and published by CRC Press. This book was released on 1986-11-01 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Contaminants in the Subsurface by : National Research Council
Download or read book Contaminants in the Subsurface written by National Research Council and published by National Academies Press. This book was released on 2005-04-23 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: At hundreds of thousands of commercial, industrial, and military sites across the country, subsurface materials including groundwater are contaminated with chemical waste. The last decade has seen growing interest in using aggressive source remediation technologies to remove contaminants from the subsurface, but there is limited understanding of (1) the effectiveness of these technologies and (2) the overall effect of mass removal on groundwater quality. This report reviews the suite of technologies available for source remediation and their ability to reach a variety of cleanup goals, from meeting regulatory standards for groundwater to reducing costs. The report proposes elements of a protocol for accomplishing source remediation that should enable project managers to decide whether and how to pursue source remediation at their sites.
Author :United States. Environmental Protection Agency. Office of Solid Waste and Emergency Response Publisher : ISBN 13 : Total Pages :177 pages Book Rating :4.:/5 (571 download)
Book Synopsis Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils by : United States. Environmental Protection Agency. Office of Solid Waste and Emergency Response
Download or read book Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils written by United States. Environmental Protection Agency. Office of Solid Waste and Emergency Response and published by . This book was released on 2004 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Detailed Field Investigation of Vapor Intrusion Processes by :
Download or read book Detailed Field Investigation of Vapor Intrusion Processes written by and published by . This book was released on 2008 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this demonstration study was to identify a cost effective and accurate protocol for investigation of vapor intrusion into buildings overlying contaminated groundwater. Intensively monitored sites, such as the Borden Landfill in Canada, have greatly contributed to our understanding of the physical and chemical processes that control the transport of chemicals in groundwater. For this project, we have used a similar approach (i.e., intensively monitored sites with specially-designed monitoring networks) to address the critical groundwater-to-indoor air vapor intrusion pathway. For this demonstration, vapor intrusion site investigations have been completed at a total of three buildings located at two demonstrations sites: two single-family residences near Hill AFB and a small office building at Altus AFB. For each site, the investigation program consisted of an initial sample point installation and sampling event and one (Hill AFB) or two (Altus AFB) follow-up sampling events.
Book Synopsis Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils - Scholar's Choice Edition by : U S Environmental Protection Agency
Download or read book Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils - Scholar's Choice Edition written by U S Environmental Protection Agency and published by . This book was released on 2015-02-16 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
