1. U.S. Environmental Protection Agency. Health risk and exposure assessment for ozone. https://nepis.epa.gov/Exe/ZyPDF.cgi/P100KBUF.PDF?Dockey=P100KBUF.PDF. Published August 2014. Accessed October 1, 2018.
2. U.S. Environmental Protection Agency. Integrated science assessment for carbon monoxide. https://ofmpub.epa.gov/eims/eimscomm.getfile?p_download_id=494432. Published January 2010. Accessed October 1, 2018.
3. U.S. Environmental Protection Agency. Integrated science assessment for oxides of nitrogen – health criteria. http://ofmpub.epa.gov/eims/eimscomm.getfile?p_download_id=526855. Published January 2016. Accessed October 1, 2018.
4. U.S. Environmental Protection Agency. Integrated science assessment for sulfur oxides – health criteria. http://ofmpub.epa.gov/eims/eimscomm.getfile?p_download_id=533653. Published December 2017. Accessed October 1, 2018.
5. U.S. Environmental Protection Agency. Integrated science assessment for particulate matter. http://ofmpub.epa.gov/eims/eimscomm.getfile?p_download_id=494959. Published December 2009. Accessed October 1, 2018.