Which of the following statements regarding the physical and chemical dynamics of global w… — State PSC Exam

Which of the following statements regarding the physical and chemical dynamics of global warming and atmospheric ozone are correct?

Stratospheric ozone absorbs harmful ultraviolet-B ( $UV\text{-}B$ ) radiation, preventing the majority of high-energy solar radiation from reaching the Earth's surface.Answer
B
Carbon dioxide ( $CO_2$ ) possesses a significantly higher Global Warming Potential ( $GWP$ ) than methane ( $CH_4$ ) over a 100-year time horizon.
Nitrous oxide ( $N_2O$ ) acts both as a greenhouse gas in the troposphere and as a major catalyst for ozone depletion in the stratosphere.Answer
D
Tropospheric ozone acts primarily as a radiative cooling agent by scattering incoming shortwave solar rays back into space.

Answer

The statements confirming that stratospheric ozone absorbs harmful UV-B radiation and that nitrous oxide acts as both a greenhouse gas and an ozone-depleting agent are correct.

The statement regarding stratospheric ozone is correct because the ozone layer shields the biosphere from harmful UV-B rays. The statement regarding nitrous oxide is also correct because N2O is both a powerful greenhouse gas in the troposphere and the single largest ozone-depleting substance emission in the 21st century.

Step-by-Step Solution

Evaluate the statement concerning stratospheric ozone absorption

Stratospheric ozone absorbs high-energy solar UV-B radiation (

280\text{--}315\text{ nm}

), which is vital for preventing radiation damage on Earth.

This statement accurately reflects the protective role of ozone in the stratosphere.

Compare Global Warming Potentials of carbon dioxide and methane

CO_2

is the reference gas with a

GWP = 1

, whereas

CH_4

has a 100-year

GWP

of around

28\text{--}36

The statement incorrectly claims

CO_2

has a higher

GWP

than

CH_4

Analyze the dual atmospheric impacts of nitrous oxide

N_2O

traps heat in the troposphere (

GWP \approx 273

) and decomposes into

NO_x

radicals in the stratosphere, catalytically destroying

O_3

This statement correctly describes both the climate warming and ozone depletion effects of nitrous oxide.

Examine the radiative property of tropospheric ozone

Tropospheric ozone is a key greenhouse gas that absorbs outgoing longwave infrared radiation, warming the lower atmosphere.

The statement incorrectly describes tropospheric ozone as a cooling agent that scatters solar rays.

Key Concept

Dual roles of atmospheric gases in climate forcing and stratospheric ozone chemistry

Question

Answer

Step-by-Step Solution

Key Concept

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