system
Given the following post, respond as if you're commenting on Reddit:
human
If you were to plant a bunch of trees in a place that doesn't have a large tree count, such as England, would there be a noticeable difference in air quality?

Does planting more trees in a concentrated area provide a noticeable difference air/oxygen quality in the area?
gpt
Not particularly. The vast majority of oxygen comes from oceanic algae, not trees. Atmospheric gasses also rapidly mix in turbulent air, eliminating local differences. 

Air Quality is a different thing to oxygen content though, and is generally concerned with the parts-per-million (PPM) or parts-per-billion (PPB) of some pollutant. 

Shanghai for example would have far worse air quality than Copenhagen, but the same gas percentages.