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New data on background indoor air levels of volatile organic compounds (VOCs) and air-phase petroleum hydrocarbons (APH) in office buildings and schools

Published by:
Haley & Aldrich

Rich Rago, Vapor Intrusion Practice Leader, Haley & Aldrich
Alpha Analytical

The U.S. Environmental Protection Agency (USEPA) and state regulatory agencies provide guidance for comparing indoor air data to background concentration data to assess the soil vapor intrusion pathway at contaminated sites. The current background values used for non-residential indoor air background studies generally include data up to 20 years old, with sampling by multiple methods and focus on varying populations.

As these studies may not be well-suited for current evaluation of indoor air quality in office buildings and schools, Haley & Aldrich and Alpha Analytical recently completed a background indoor air study. The study includes the collection of background indoor air samples for office buildings (59 samples) and schools (25 samples) located in 18 states.

The study was designed with input from USEPA and Massachusetts Department of Environmental Protection, and sampling was conducted generally during winter months of 2013, 2014, and 2015. Preliminary results confirm hydrocarbons, alcohols, Freons, and 1,2-dichloroethane are prevalent in office and school indoor air background, and that other chlorinated solvents may also be present. Haley & Aldrich staff are currently evaluating over 14,000 data points generated through the study.

As the data is analyzed and presented throughout the country, we will post updates here.

Related downloads:
Initial analysis of the study by Rich Rago, Haley & Aldrich Vapor Intrusion Practice Leader

•  June 2015: Licensed Site Professional Association (LSPA) presentation
•  June 2015: Environmental Business Council (EBC) New England presentation