"The environmental cost of this is a negative externality that I feel this move reduces" I don't think it is an externalized cost given that you pay for your t

"The environmental cost of this is a negative externality that I feel this move reduces" I don't think it is an externalized cost given that you pay for your trash to be disposed of. (I assume you aren't littering) This would be an internalized cost. You are paying for the cost of your own waste.