Geologic Resources: Links for Geoscientists & Engineers  The Friendly Woolly Mammoth  The Friendly Dinosaur
EVALUATION OF INDOOR AIR QUALITY

 

 
 
OUR SITE
Home
Resources
Software
Books
Our Mall
Geolinks
Geoforum
Geonews
Auctions
Networking
Jobs
Free Stuff
Exchange
Policies
Credits



   
    Evaluating Indoor Air

When a contaminated site has buildings on and/or adjacent to the site and the contaminants of concern (COCs) include volatile organic compounds (VOCs), an evaluation of the impact on indoor air may be necessary.  

Migration of ContaminantsIllustration of groundwater contamination plume beneath an industrial complex

The drawing on the right illustrates how a contaminant source  (industrial area in this case) may result in groundwater contamination beneath the facility.   Groundwater flow then transports contaminants downgradient where they may impact other properties.    If any of the contaminants in the groundwater are volatile, they may rise through the overlying unsaturated soils and enter indoor air.   The level of the building that is impacted first by contaminants from the subsurface, is the lowest level.   In buildings with a basement, the basement air is usually impacted first and by the highest concentrations of  contaminants.  

Typical residential buildingSampling

Samples may be collected on the site with a portable analyzer, or collected in containers for either laboratory analysis or analysis in a field laboratory.   Tubes with absorbent material may also be used to collect gas samples over a measured period of time.   The samples should be collected to reflect the air volume that is being evaluated (e.g. in a room at breathing level).   Enough samples should be collected to evaluate patterns of contaminant entry and migration within the building.   Containers may include Tedlar® bags, a materialTypical basement resistant gas permeation and Summa canisters, containers constructed of stainless steel.   Samples can be "grab samples" or air samples collected over a measured period of time.   Sometimes soil gas samples are collected from beneath or adjacent to a building to evaluate the gas concentrations in the subsurface that have not been affected by activities or substances that are in the building.   Buildings commonly contain numerous volatile substances including:

  • The presence of volatile substances that may be used or stored in the building (e.g. paint, solvents, and cleaning agents).
  • The building may be heated by a system that burns hydrocarbons (e.g. fuel oil or natural gas). Volatile hydrocarbons may be present in indoor air from the heating system, storage, or transmission lines.

Analysis

Analyses that are conducted depend on the objective of the evaluation.   Analytical methods may be those of regulatory agencies (e.g. U.S. EPA or State regulatory agencies).   We have found that a screening assessment of the impact on indoor air can be made using the Johnson and Ettinger Model on the U.S. EPA website

Some Useful Links

Following are some hyperlinks that can further assist with the evaluation of indoor air quality:

 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
 

Google
 
 

Click here for Geologic Resources Home Page Click here for Geologic Resources Resources Page Click here for Geologic Resources Free Stuff Page Click here for Geologic Resources Links Page Click here for Geologic Resources Link Directory Click here for Geologic Resources Submission Page
Click here for Geologic Resources Software Page Click here for Geologic Resources Computer Store Click here for Geologic Resources Books Page Click here for Geologic Resources Auctions Links Page Click here for Google Search Engine Click here for Yahoo Search Engine and Links
©1998-, Geologic Resources, All Rights Reserved

Tools Online Tools