Which statement best describes the difference between direct air capture and capture at the source of emissions?

• A. Capture at source removes CO2 before it enters the atmosphere from a point source.
• B. Direct air capture removes CO2 already present in ambient air.
• C. Both require energy and infrastructure.
• D. They are the same process.

Answer: (C)

The key idea is that carbon capture, no matter where it happens, needs power and structure to work. Both direct air capture (pulling CO2 from the surrounding air) and capture at the emission source (this CO2 before it leaves the smokestack or exhaust) rely on specialized equipment, energy to operate that equipment, and the infrastructure to handle, transport, and store the captured CO2.

Direct air capture deals with CO2 already dispersed in ambient air, so it must concentrate dilute CO2 and push it through capture materials or chemical processes, which tends to be energy-intensive. Capture at the source works with higher CO2 concentrations in exhaust streams, which can reduce energy per ton and simplify some aspects of capture, but it still requires substantial energy and a network of equipment and storage or transport systems.

So the best statement emphasizes a fundamental reality: both methods require energy input and the necessary infrastructure to capture, move, and store the CO2. The other ideas describe differences in where or how capture happens, but they don’t capture this essential requirement that applies to both approaches.