•	Free Indoor Air Unit Conversion Tool
•	New San Francisco Bay WQCB Screening Levels
•	California Vapor Intrusion Symposium
•	New Hampshire Vapor Intrusion Screening Levels
•	Indoor Air Analytical Laboratories
•	Hand Held Screening Instrument
•	Ambient Air Levels of Volatile Organics
•	EnviroGroup Seattle Office

Featured Links:

•	EPA National Air Toxics Assessment
•	California Air Resources Board
•	Indiana Office of Air Quality

New San Francisco Bay WQCB Screening Levels
On July 21, 2003 the San Francisco Bay Water Quality Control Board released the interim final document “Screening for Environmental Concerns at Sites With Contaminated Soil and Groundwater”. This comprehensive document covers all pathways of human and environmental exposures and includes over 100 chemicals in its tables of screening values. A risk level of 10 –6 for cancer and a hazard quotient of 0.2 for non cancer effects and Cal EPA toxicity factors are used to calculate the screening levels.

Regarding vapor intrusion specifically, Volume 1 includes the text and summary screening levels for indoor air and shallow soil gas in Table E. Screening levels are provided for both residential and commercial/industrial land uses. The recommended approach to screening for vapor intrusion is first groundwater screening, then collection of shallow soil gas data over the portions of the plume where the groundwater screening levels are approached, then finally collection of indoor air samples where the soil gas screening levels are approached. Shallow soils are defined as 0-3 meters.

Volume 2 contains all the background information used in developing the screening levels and serves as an excellent reference. Table E-1a provides groundwater screening levels for indoor air impacts. It includes values for residential and commercial/industrial land use as well as both high and low/moderate porosity vadose zone soils. Table E-1b provides soil screening values for indoor air impacts for both land uses. Table E-2 provides shallow soil gas screening levels and Table E-3 provides indoor air screening levels for both land uses. Electronic spreadsheets are provided to allow back calculation of a screening level from an input target risk in Appendix 4.

This comprehensive document can be found at:

 

California Vapor Intrusion Symposium
The Groundwater Resources Association of California is presenting a symposium: “Subsurface Vapor Intrusion to Indoor Air: When Is Soil and Groundwater Contamination an Indoor Air Issue?” This one-day symposium will be held twice: September 30, 2003 in San Jose and October 1, 2003 in Long Beach, and is sponsored by the California Department of Toxic Substances Control, the San Francisco Water Quality Control Board, and EPA Region 9. EnviroGroup Limited is one of the co-sponsors. The symposium will provide the California perspective on vapor intrusion and will include a California case study. Details can be found on the web site:

 

New Hampshire Vapor Intrusion Screening Levels
The New Hampshire Department of Environmental Services updated its “Draft Residential Indoor Air Assessment Guidance Document” in March 2000. Table 1 of that document includes indoor air screening levels for 32 compounds calculated at the 10-6 cancer risk level. Table 1 also includes acute levels for the same 32 compounds. The document includes an indoor air sampling protocol and recommendations for analytical methods. It can be found at the website below, under Publications, Reports and Document Listings, and then Site Remediation.

New Hampshire also has screening levels for groundwater for protection of indoor air. They are included in Table 2 of the document: “Contaminated Sites Risk Characterization and Management Policy”. Table 2 was last updated June 6, 2003. The GW-2 groundwater standards are designed for screening for potential indoor air impacts. This document can also be found at the website below, under Publications, Reports and Document Listings, and then under Risk Characterization Management Policy:

 

Indoor Air Analytical Laboratories
The Colorado Department of Public Health and Environment has found four analytical laboratories to have the demonstrated ability to produce acceptable volatile organic indoor air data consistent with CDPHE guidelines. The laboratories (in alphabetical order) are:

Air Technology Laboratories, City of Industry, CA,
888-920-4032

Environmental Chemistry Services, Inc., Castle Rock, CO 303-850-7606

Johns Manville Technical Center, Littleton, CO,
303-978-5200

Severn Trent Laboratories, Santa Ana, CA,
714-258-8610

This information is being provided for the convenience of our readers. EnviroGroup is not associated with nor does it endorse any particular laboratory. This is not an exclusive list: other laboratories may also be qualified to perform state of the art indoor air analyses (e.g., TO-15) to the very low reporting limits required by current screening/action levels. CDPHE's requirements for indoor air analytical procedures can be found at our website under Vapor Intrusion, Colorado links:

 

Hand Held Screening Instrument
Rae Systems offers a hand held photo ionization detector (PID) reported to be capable of detecting VOC’s in the part per billion range. It has been reported that this instrument can be used effectively inside buildings to find indoor sources of VOCs and possibly rule out vapor intrusion from the subsurface. EnviroGroup is not associated with Rae Systems nor does it endorse any particular instrument or vendor. Information on the specific instrument , the ppbRAE, is found at:

 

Ambient Air Levels of Volatile Organics
The "featured" website links located in the left column of this newsletter (HTML version) or below (text version) provide data on ambient air levels of volatile organic compounds. The first website for the EPA National Air Toxics Assessment presents state maps showing ranges of MODELED concentrations of toxic air pollutants, by county, using 1996 data for 33 compounds.

The second link is for the California Air Resources Board website, which presents annual toxics summaries by compound.

The third link for the Office of Air Quality of the Indiana Department of Environmental Management provides information on an air toxics sampling program called TOXWatch. This two year study began June 1999 and involved sampling at numerous locations in four counties. Samples were collected every six days and analyzed for 87 chemicals.

EnviroGroup Seattle Office
EnviroGroup is pleased announce the opening of its Seattle office (effective October 2003). Although EnviroGroup has provided services from coast to coast for over a decade, including many projects in Washington and California, our new office will allow us to provide even more responsive and cost effective services in the Pacific Northwest. Click below for more information on EnviroGroup, its Denver, Boston, and Seattle offices, and services.