Table 3 PFAS terminology and species names.

Perfluorocarboxylic acids (PFCA)

PFHpA

perfluoroheptanoic acid

C₇HF₁₃O₂

0.17 y⁵⁷

Y (0.4%)

PFOA or C8

perfluorooctanoic acid

C₈HF₁₅O₂

1.7–2.7 y^57,58

Y (98.7%)

PFNA or C9

perfluorononanoic acid

C₉HF₁₇O₂

1.7–3.2 y⁶³

Y (78.1%)

PFDA

Perfluorodecanoic acid

C₁₀HF₁₉O₂

4.0–7.1 y⁶³

Y (6.0%)

Perfluorosulfonic acids (PFSA)

PFBS

perfluorobutane sulfonic acid

C₄F₉SO₃H

0.12 y⁵⁷

N

PFHxS

perfluorohexane sulfonic acid

C₆HF₁₃SO₃H

2.86–5.3 y^57,58

Y (99.0%)

PFOS

perfluorooctane sulfonic acid

C₈HF₁₇SO₃H

2.91–3.4 y^57,58

Y (100%)

PFAS precursors

MeFOSAA

2-(N-Methyl-perfluorooctane sulfonamido) acetic acid

C₁₁H₆F₁₇NO₄S

3.5 y⁶⁴

Y (3.8%)