Which of the following makes up the least percentage of landfill volume?

• A. Wood and yard wastes
• B. Rubber
• C. Paper
• D. Plastic

Answer: (D)

In landfills, the space a material takes up depends on how bulky it is and how well it can be compacted. Bulky, fluffy wastes like wood and yard debris create a lot of air gaps and occupy more volume, and paper adds to that bulk as well. Paper also tends to break down over time, but its initial volume in a landfill can be quite large due to its light, airy nature. Rubber, especially in whole tires, can occupy substantial space because of their shape and low density, unless they’re shredded.

Plastic, on the other hand, tends to be more compactable and denser, so for a given amount of waste it generally occupies less landfill volume. Plastics also don’t contribute as much to air-space bulk as organics do, and while they persist, their tendency to pack tightly means they take up relatively less space than bulky organics. So, among the options, plastic ends up contributing the smallest share of landfill volume.