I wonder if the author realizes what a waste it is to drive a big car (let alone a fire truck) to the grocery store. We all love nature. We go out of our way to live in a place where it is more spectacular. And yet we do our best to shit on it with the damn gas guzzlers. Because, you know, it's fun!
The grocery store is perhaps a mile away, and he perhaps goes twice a week? So that's 100 miles/year, two orders of magnitude away from the national average. It's also substantially less co2 production than a flight from SFO to Hawaii.
Oh, and since we are talking about diesels, they produce diesel particulate matter, ultrafine particles that can cause anything from cancer to nausea. Even modern diesel engines can't completely filter them.