Identifying Gas with Lowest Residence Time
The residence time of a gas in the atmosphere is the average time it spends there before being removed or transformed. Gases with shorter residence times are removed more quickly.
Comparing Atmospheric Residence Times
Let's examine the approximate atmospheric residence times for the given gases:
| Gas | Approximate Residence Time (Years) |
|---|---|
| $\text{CO}_2$ | 100 - 200 |
| $\text{N}_2\text{O}$ | ~114 |
| CFCs | Decades to Millennia (Highly Variable) |
| $\text{CH}_4$ | 8 - 12 |
Conclusion on Residence Time
Comparing the residence times:
- Methane ($\text{CH}_4$) has the shortest residence time, typically around 8 to 12 years.
- Carbon Dioxide ($\text{CO}_2$) and Nitrous Oxide ($\text{N}_2\text{O}$) have significantly longer residence times.
- Chlorofluorocarbons (CFCs) generally have very long atmospheric lifetimes, often much longer than $\text{CO}_2$ or $\text{N}_2\text{O}$.
Therefore, methane ($\text{CH}_4$) is the gas with the lowest residence time among the options provided.
Important Questions from Global Environmental Issues
pH of dust free and unpolluted rainwater is 5.6 due to dissolution of
The major component of volcanic gas emissions is
Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R). Read the statements and choose the correct answer using the code given below.
Assertion (A) : CFCs are able to penetrate the stratosphere.
Reason (R) : CFCs are highly unreactive.
Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R). Read the statements and choose the correct answer using the code given below.
Assertion (A) : In general a rise in temperature of water adversely affects the aquatic life.
Reason (R) : An increase in temperature causes hyperoxia among aquatic species.
Which of the following is not a precursor of classical smog?
