# What does "ppm" mean with respect to concentration?

$\text{Concentration"-="Amount of substance"/"Volume of solution}$, and typically we get units of $m o l \cdot {L}^{-} 1$ or $g \cdot {L}^{-} 1$ (note $1 \cdot m g \cdot {L}^{-} 1 \equiv \text{1 ppm}$). Anway we need some context to address what you want to know.