What is environmental chemistry?

Environmental chemistry involves the study of chemicals and chemical processes within the air, water, and soil. It also involves studying how these chemicals get there, what they do, and how humans are intertwined in all of this.

Environmental chemistry is more than just water, air, soil, and chemicals. People in this field use math, biology, genetics, hydrology, engineering, toxicology, and a lot more to help answer important questions about our environment, the chemicals therein, and what role people play in all of this or how it impacts us as a result.

I have heard of environment and chemistry separately but how to interpret when they are combined as "environmental chemistry"?