An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

EPA ExpoBox

Exposure Factors Handbook Chapter 3

UPDATE: EPA released an update to Chapter 3 in February 2019, that document is included below.

Exposure Factors Handbook: 2011 Edition. The Exposure Factors Handbook provides information on various physiological and behavioral factors commonly used in assessing exposure to environmental chemicals.Cover of the 2011 Edition of the EPA Exposure Factors Handbook.Click to learn more about the full 2011 Edition Handbook and recent updates.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.