What was the typical metal abundance of early stellar nurseries (Pop III) compared to modern Population I stars?

Pop III had metals around one part in $10^7$ of the mass, while Pop I has one to two percent.

The chemical composition of stellar nurseries underwent a massive transformation between the first generation and modern stars. The earliest clouds, formed just after the universe cooled, were composed of nearly pure hydrogen and helium, meaning their metal abundance—anything heavier than helium—was exceptionally low, theoretically around one part in $10^7$ (one millionth) of the total mass. In stark contrast, stars forming today, known as Population I stars, are enriched by the remnants of previous stellar deaths. Modern stellar populations exhibit metal abundances ranging from one percent up to two percent of their total mass, demonstrating the profound chemical evolution facilitated by the initial supernovae.