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Posts Tagged ‘EPA Method TO-15’

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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Update to Massachusetts Air Petroleum Hydrocarbons (APH) Method

Thursday, April 16th, 2009

MassDEP APH MethodThe Massachusetts Department of Environmental Protection (MassDEP) recently updated and finalized their Air-Phase Petroleum Hydrocarbons (APH) analytical method. The APH method, which had been in draft format since February 2000, was completed last year by a MassDEP Workgroup and approved after a month long public comment period in December 2008. The committee was comprised of MassDEP personnel, laboratory experts and data users.

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Analytical Considerations for Air Samples for Vapor Intrusion Investigations

Monday, February 5th, 2007

The term “vapor intrusion” refers to the migration of volatile chemicals from subsurface contaminated sources into overlying residential or commercial structures. “Historically, it was thought that vapor intrusion was only an issue where the source of the contaminants was very shallow and the magnitude of the contamination was very great. It is now known that the previous assumptions about the mechanisms that could lead to exposure to vapor intrusion were not complete (NYS DEC DER Vapor Intrusion Guidance).” For a growing number of federal, state and local agencies, as well as environmental consultants and laboratories, vapor intrusion could emerge as the next major environmental challenge.

Vapor intrusion is not a new phenomenon— for some environmental experts, it has been recognized as a potential pathway of contamination for almost 20 years. In the late 1980s, the first vapor intrusion studies were carried out to evaluate potential health effects from chronic exposure to volatile organic compounds. Presently, vapor intrusion is of growing concern to the environmental community due to a number of factors, such as increased recognition of it as a potential pathway for exposure and the risks associated with that exposure, as well as the location and the number of potential sites for investigation and remediation. With this increased focus comes ongoing debate regarding the mechanism of the exposure pathway, compliance concentrations of contaminants, identification of sites, sampling approaches, analytical methodology, use and validity of current models, screening approaches, and risk assessment, among other topics.

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