RAS question
Direct Air Capture (DAC) technology:
Correct answer: (B) Removes CO2 directly from ambient air.
Direct Air Capture technology removes carbon dioxide directly from ambient air.
Explanation
Direct Air Capture is a carbon dioxide removal technology, not a general air-cleaning device. The Department of Energy explains that DAC takes CO2 from ambient, still air, after which the separated CO2 can be stored deep underground or converted into products. DAC uses chemical solvents or solid sorbents to capture CO2 directly from the air rather than from a point source such as an industrial stack. In solvent-based systems, chemicals remove CO2 as air passes through; in sorbent-based systems, filters chemically bind CO2 and later release it as a concentrated stream. This is why DAC is discussed in net-zero contexts, even though it remains expensive at about $250-600 per tonne of CO2.
Why the other options are wrong
- (A) Filtering dust from air describes air purification, whereas DAC targets carbon dioxide removal from ambient air.
- (C) DAC does not produce hydrogen from air; its purpose is to capture CO2 and then store or use the separated carbon dioxide.
- (D) Creating artificial wind is unrelated to DAC, which passes air through solvents or sorbents to remove carbon dioxide.
Concept
This tests Science & Technology coverage of climate-change mitigation technologies, especially carbon dioxide removal. It recurs in RAS-style questions because DAC links a named emerging technology with net-zero emissions and diffuse emissions control.