You’re missing some deeply important context there, which is that those measurements are for outdoor atmospheric CO2 only.

Average indoor air quality ranges from 400-1000 ppm CO2, with adverse mental effects starting to appear close to 2000 ppm.

In that context, you can see why a 50 ppm difference is marginal. This is why asking an LLM is not generally a great idea for understanding something - you need to follow it up with more research.