CS278160-C Page 1
Agency for Toxic Substances and Disease Registry
Division of Community Health Investigations
The family tree of per- and
polyfluoroalkyl substances (PFAS) for
environmental health professionals
Names and abbreviations
6/9/17
This fact sheet tells you about chemical names within the family of per- and polyfluoroalkyl
substances (PFAS) and their basic chemical structure. It also spells out abbreviations for
common PFAS.
PFAS are a family of man-made chemicals that contain carbon, fluorine, and other elements.
The family tree image, Figure 1, shows some of the different families of PFAS. For simplicity, it
does not include all PFAS subfamilies. Follow along – starting at the “fallen apple” of PFC and
then continuing up the tree trunk into the branches.
PFC
In the past, PFC stood for
perfluorinated chemicals.
However, using the abbreviation
PFC can be confusing. This
abbreviation is also used
to mean perfluorocarbons.
Perfluorocarbons are a different
family of chemicals, also known as
greenhouse gases.
The term PFC has fallen off the
family tree, but it remains in the
diagram as a reminder of past use.
You may still see informational
materials using the term “PFC”
instead of PFAS.
PFAS
Current nomenclature favors “PFAS” which are per- and polyfluoroalkyl substances. The PFAS
family includes hundreds of chemicals. See Table 1 (next page) for some abbreviations and
chemical names.
Figure 1.
Family Tree
of Per- and
polyfluoroalkyl
Substances
Polyfluoro-
alkyls
PFOA
PFDA
PFNA
PFOS
PFHxS
PFAS
Perfluoro-
alkyls
PFC
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Table 1. Common PFAS: Abbreviations and Names
Abbreviation Chemical name
PFOS Perfluorooctane sulfonic acid
PFOA (aka C8) Perfluorooctanoic acid
PFNA Perfluorononanoic acid
PFDA Perfluorodecanoic acid
PFOSA (aka FOSA) Perfluorooctane sulfonaminde
MeFOSAA (aka Me-PFOSA-AcOH) 2-(N-Methyl-perfluorooctane sulfonamido) acetic acid
Et-FOSAA (aka Et-PFOSA-AcOH) 2-(N-Ethyl-perfluorooctane sulfonamido acetic acid
PFHxS Perfluorohexane sulfonic acid
Chemical Structure
All PFAS contain a chain of carbon atoms bonded
to fluorine atoms. Some also have a functional
group at the end of the chain. These structures
are the basis for different chemical properties and
different chemical names.
In perfluoroalkyl substances all carbons except the
last one are attached to fluorines. The last carbon
attaches to the functional group. See Figure 2.
In polyfluoroalkyl substances at least one (but not
all) carbons are attached to fluorines.
Note about Plurals
PFAS is the abbreviation for per- and polyfluoroalkyl substances (plural), so you don’t technically
need another “s.” You may see “PFASs” written, but ATSDR’s preference is to use PFAS. When you
write about PFAS make sure you use correct subject-verb agreement – PFAS is a plural noun,
so it must be used with a plural verb. For example “These are the most common PFAS found in
people.”
You can also use the term “PFAS family” with a singular verb.
It may feel awkward to use PFAS as a plural when it sounds singular, but with practice, it will
feel right.
Figure 2. Perfluorooctanoic acid
(PFOA), a perfluoroalkyl substance
Image credit: NIEHS.
References
Buck et al 2011. Perfluoroalkyl and Polyfluoroalkyl Substances in the Environment: Terminology, Classification, and Origins.
Integrated Environmental Assessment and Management. v7, (4), pp. 513–541.
CDC. 2009. Fourth National Report on Human Exposure to Environmental Chemicals. Atlanta, GA: Centers for Disease Control
and Prevention. p. 247 – 257.
