Understanding Ozone Depletion Potential (ODP)
Ozone Depletion Potential (ODP) is a relative measure of a substance's ability to destroy the ozone layer compared to a reference substance (CFC-11, which has an ODP of 1.0).
Comparing ODP Values
Different halogenated hydrocarbons have varying ODPs:
- CFC-12: Has an ODP of approximately 1.0. It was widely used but is now phased out due to its high ODP.
- Halon-1211: Used in fire extinguishers, it has a very high ODP, ranging from 3.0 to 5.0.
- HCFC-22: A hydrochlorofluorocarbon with an ODP of about 0.055. While lower than CFCs, it still contributes to ozone depletion.
- HCFC-123: Another hydrochlorofluorocarbon, specifically designed as a lower-ODP alternative to some CFCs. Its ODP is approximately 0.02.
Identifying the Lowest ODP
Comparing the approximate ODP values:
- HCFC-123: 0.02
- HCFC-22: 0.055
- CFC-12: 1.0
- Halon-1211: 3.0 - 5.0
Based on these values, HCFC-123 exhibits the lowest Ozone Depletion Potential among the choices.
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?
