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Posts Tagged ‘indoor air’

Vapor Intrusion Investigations: Air Sampling Tips for Meeting Data Quality Objectives

Monday, September 26th, 2011

N. Dagnillo1, L. Hill2, A. Fortune3, A. Smith4, and S. Thompson2
1Trihydro Corporation, 3001 E. Pershing Blvd, Suite 115, Cheyenne, WY 82007
2Trihydro Corporation, 1537 Riverside Ave., Suite 101, Fort Collins, CO 80524
3Columbia Analytical Services, Inc., 2655 Park Center Drive, Suite A, Simi Valley, CA 93065
4Trihydro Corporation, 9460 Calle Milano, Atascadero, CA 93422

Vapor intrusion is a fate and transport process characterized by the upward movement of volatile chemicals from subsurface contamination (e.g., buried waste, contaminated groundwater) into overlying buildings. The potential for adverse human health effects from exposure to indoor air vapors has motivated private, state, and federal entities to develop guidance documents and protocols specific to the collection and analysis of soil vapor data.

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Vapor Intrusion/Vapor Encroachment: ASTM’s New Standard Guide

Monday, February 28th, 2011

Vapor Intrusion in the HomeBy Steve Wing

On June 14, 2010, ASTM International (formerly the American Society for Testing and Materials) issued E 2600-10, Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions. This document revises and supersedes ASTM E 2600-08, Standard Practice for Assessment of Vapor Intrusion into Structures on Property Involved in Real Estate Transactions, issued on March 3, 2008.1

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Total Volatile Organic Compound (TVOC) Measurement for LEED/Green Building Evaluation

Wednesday, May 27th, 2009

LEED Testing

Background

Total Volatile Organic Compounds (TVOC) may be evaluated when building designers/managers are pursuing the Leadership in Energy and Environmental Design Green Building Rating System for New Construction (LEED-NC) EQ Credit 3.2. The latest LEED-NC guidance document specifies that the maximum allowed concentration of TVOC measured in a building (post construction, pre-occupancy) is 500 µg/m3; the guidance also mentions using the sampling/analytical methods in the US EPA Compendium of Methods for the Determination of Air Pollutants in Indoor Air. However, none of these sampling and analytical methods address TVOC in particular, and thus the existing methods must be modified. In addition, TVOC is not defined (in terms of boiling point range, etc.) in the latest LEED-NC guidance and therefore is left open for interpretation; historically, many definitions of “TVOC” exist in literature.

For TVOC measurement, the analytical technique used must always reference one compound for calibration purposes. All compounds detected are then assumed to have the same response factor as the calibration compound. For instance, handheld instruments are most often calibrated using isobutylene or methane, and laboratory-based methods may reference TVOC as hexane (C6), toluene, or some other chemical species.

In practice, indoor air quality practitioners may use several different techniques for evaluating TVOC in buildings. Each sampling & analytical method has its own benefits and drawbacks, cost implications, and applicability.

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Soil Gas Sampling

Tuesday, January 15th, 2008

Soil-Gas-SamplingSoil gas sampling is increasing in frequency across the country as vapor intrusion continues to gain regulatory attention. When evaluating the potential for vapor intrusion at a particular site, it is useful to collect soil gas samples to find out how vapors and contaminants of concern are migrating in the subsurface, and whether or not those vapors are migrating indoors. Soil gas sampling, used in conjunction with state specific screening criteria and/or modeling, is often an intermediate step between screening based on groundwater concentration and collecting indoor air samples.

The goal of soil gas sampling is to collect a sample of the vapor that resides in the interstitial soil pores near a source of contamination and/or near a potential receptor structure. To sample soil gas, a temporary or permanent soil vapor probe is installed. If the well is installed incorrectly or is not sealed properly, leaks to the ambient air may occur. This can dilute or otherwise influence the concentrations seen, potentially leading to incorrect decision making.

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