What's Greener: Lunch from a Food Truck or a Restaurant?

• Natural gas v. propane:

  restaurants typically rely on piped-in natural gas to heat their fryers and griddles, while trucks and carts use tanks of propane. When burned, propane emits a bit more carbon dioxide than natural gas does, per unit of heat it generates. But unignited natural gas contains 95 percent methane, while propane contains none. If methane reaches the atmosphere—through leaky pipes or equipment, or burners that don't light properly—it's a far more potent greenhouse gas than carbon dioxide.

• Generators: Size matters, as does how reliant the area in which the cart or truck is located uses coal. "Onboard generators also emit more carbon dioxide than utility-delivered electricity." So, most likely, score one for the sit-down.
• The eating area: "In the average full-service restaurant, lighting, heating, ventilation, and air conditioning can account for 41 percent of the establishment's total energy use." A truck doesn't have to maintain an eating area. Score one for the trucks.
• Driving: Physical restaurants don't move, and trucks use gas (though some, granted, use veg oil) to get from commissary to spot to spot to spot and back to the commissary. Plus, back at the commissary there are things the truck relies on to dispose of waste, to refrigerate, heat, and so on, which is part of the operation's overall footprint.

Conclusion: Errr, it's a draw. Or, it's too soon to tell. More study is needed on the eco footprints of trucks versus restaurants to declare which is greener. Ultimately, though, you can make some choices to make your lunch more eco-friendly, no matter where you have it: "First, eat less. (At the very least, don't buy more than you can finish.) Second, scale back on meat and dairy. And if a van with tasty falafels is parked right outside your office building and the only other decent restaurant is a 10-minute drive away, then by all means: Keep on truckin'."