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Source Ranking Database (SRD) for Indoor Air Pollutants

Search EPA ArchiveWhat does SRD do?

  • Performs a systematic screening-level review of over 12,000 potential indoor pollution sources to identify high-priority product and material categories for further evaluation.
  • Can also identify the products that have contained a specific chemical.

How does SRD work?

  • Produces risk-based rankings by multiplying an estimated indoor-air concentration by a hazard score for each chemical in a given product or material and for each environment in which the product/material is used.
  • Allows users to display the scores for constituent chemicals, as well as the overall product scores and rankings.
  • Instructions to install and run the model are not presented here.

What do I need to use SRD?

  • SRD contains all of the information needed to create product rankings. No specific user inputs are required.
  • Users can create their own product groupings in addition to the default groupings provided by the program (these are based on Standard Industrial Classification codes).
  • Users select the indoor environments (e.g., office building, residence, hospital, shopping mall) to be evaluated by the ranking algorithm.
  • Users also choose between 'high' and 'average' values for key exposure parameters (e.g., product usage rates) evaluated by the ranking algorithm.

How are SRD data used?

  • To produce ranked lists of products or product categories that contribute to indoor air pollution.
  • To identify the relative contribution of each constituent chemical to a consumer product's risk score.
  • To identify what products a specific chemical has been used in.

What type of computer system do I need?

Hardware: IBM-compatible computer with a 486 or Pentium microprocessor (minimum speed: 33 MHZ) and 640K memory.

What is SRD's status and availability

A final version of this program is currently available in a Windows-based format. SRD has been peer reviewed by the Science Advisory Board and the comments from that review have been incorporated into the model. This model was developed under contract by Versar Inc. for the EPA Office of Pollution Prevention and Toxics, Economics, Exposure, and Technology Division, Exposure Assessment Branch (EAB).

Instructions and the downloadable .exe file

SRD Questions/Answers

  • Where can I find information about how SRD estimates the ranking of products?

    The model documentation is contained in the help screens within the model and in greater detail in the following two documents: Source Ranking Database, Volume 1: Guide and Documentation, Oct. 2003 and Source Ranking Database, Volume 2: Appendices, April 2003.

  • Has the SRD been peer reviewed?

    The SRD was reviewed by EPA’s Science Advisory Board (SAB) in July 1997. The SAB’s final report, contained recommendations for a variety of changes and improvements to the SRD. The primary comments from the SAB review related to the algorithm used to rank products. In particular, the SAB Committee recommended that the algorithm be reviewed and that attention be paid to several issues such as the overall sensitivity of the algorithm to variability in the component factors and in the hazard scale. In addition, several additional recommendations were made including: a) addition of additional exposure sources to SRD; b) addition of octanol/water partition coefficient and Henry’s Law ratio so that sorption/desorption and volatilization processes can be better addressed; and c) consideration of the need for regular updates and accessibility of the database to the public.

  • What types of formulation data were used in the SRD?  How robust are the data sets in the SRD?

    Much of the information in the Source Ranking Database is from secondary sources and has generally not been verified against primary sources.  The formulations data sets are generally pre-1990 or are based on published formulary text books (e.g, Advanced Cleaning Product Formulations by Ernest W. Flick).   Additionally, many values (i.e., time used, amount used, indoor environment product used in, etc.) needed for the exposure calculations are based upon professional judgment because of the lack of relevant data.  The hazard scores are used for screening only and do not represent official indication of hazard for chemicals.

  • I need to do a risk assessment of cleaning products, can I use the SRD?

    No. The Source Ranking Database is a tool for developing risk-based rankings of products and product categories, but does not provide actual risk assessment conclusions on products or chemicals..

The Source Ranking Database (SRD) User's Guide and Documentation (Vol. 1) and Appendices (Vol. 2) are available as PDF files.

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For more information about the model, contact:
Christina Cinalli
U.S. Environmental Protection Agency
Office of Pollution Prevention and Toxics
1200 Pennsylvania Avenue N.W. (Mail Code 7406M)
Washington, DC 20460
Phone: (202)564-8542
E-mail: Christina Cinali