Some years ago, I found out that decaf coffee has a lot more pollution due to how they process it to make it decaf then plain coffee has. Maybe you take in more of the processing solvents they use on the decaf when you are not also using regular coffee?
Also I found it interesting they have 'natural' coffee filters..I didn't know that, guess they aren't treated with bleach. My parents used to make what was called 'cowboy' coffee..you just boil water and coffee, strain and drink!
I think that herbal teas are very good, I love my Peppermint tea, anytime of the day. I usually have 1-2 Cups a day.