All flashcards
Flashcard 1: What is the primary cause of stratospheric ozone depletion?
Answer: Chlorofluorocarbons (CFCs). These synthetic chemicals break down in the stratosphere, releasing ozone-destroying chlorine atoms.
Flashcard 2: Which atmospheric phenomenon enhances ozone depletion at the poles?
Answer: Polar vortex. Circular wind patterns isolate polar air, creating conditions for severe depletion.
Flashcard 3: How does chlorine affect ozone molecules in the stratosphere?
Answer: It catalyzes the breakdown of O3. One chlorine atom can destroy thousands of ozone molecules through catalytic cycles.
Flashcard 4: Which chemical reaction describes ozone formation in the stratosphere?
Answer: O2+UV→2O; O+O2→O3. UV splits oxygen molecules, then atomic oxygen combines with O2 forming ozone.
Flashcard 5: Identify the atmospheric layer where ozone depletion occurs.
Answer: Stratosphere. This layer contains about 90% of Earth's ozone, located 10-50 km above Earth's surface.
Flashcard 6: Which gas is released from HCFCs that still affects the ozone layer?
Answer: Chlorine. HCFCs contain some chlorine but much less than CFCs, reducing ozone impact.
Flashcard 7: Name a substitute for CFCs with no ozone-depleting potential.
Answer: Hydrofluorocarbons (HFCs). These contain no chlorine or bromine, so they don't harm the ozone layer.
Flashcard 8: What is the main reason for seasonal variation in ozone depletion?
Answer: Sunlight availability. UV radiation drives chemical reactions, so depletion peaks during polar spring.
Flashcard 9: What is the significance of the Dobson Unit in ozone measurement?
Answer: Measures total ozone column. This unit quantifies the total amount of ozone in a vertical atmospheric column.
Flashcard 10: What role do refrigerators play in ozone depletion?
Answer: Release CFCs as refrigerants. Old refrigerators contain CFC coolants that escape when units are improperly disposed.
Flashcard 11: Name a natural source of halogens that can deplete ozone.
Answer: Volcanic eruptions. Volcanic emissions can release chlorine and bromine compounds into the stratosphere.
Flashcard 12: Which substance replaced CFCs due to its lower ozone-depleting potential?
Answer: Hydrochlorofluorocarbons (HCFCs). These transitional chemicals have shorter lifespans and contain less chlorine than CFCs.
Flashcard 13: What happens to CFCs in the stratosphere that causes ozone depletion?
Answer: UV light breaks them down, releasing chlorine. Photolysis by UV radiation breaks C-Cl bonds, freeing reactive chlorine atoms.
Flashcard 14: What does the abbreviation 'CFC' stand for?
Answer: Chlorofluorocarbon. These synthetic compounds contain carbon, fluorine, and chlorine atoms.
Flashcard 15: What is the global warming potential (GWP) of CFCs compared to CO₂?
Answer: High GWP. CFCs trap thousands of times more heat than carbon dioxide per molecule.
Flashcard 16: What does UV-B radiation do to living organisms?
Answer: Damages DNA. UV-B breaks chemical bonds in DNA, causing mutations and cellular damage.
Flashcard 17: How long can CFCs remain in the atmosphere contributing to ozone depletion?
Answer: Up to 100 years. CFCs have extremely long atmospheric lifetimes, causing persistent ozone depletion.
Flashcard 18: What is the primary environmental consequence of ozone layer depletion?
Answer: Increased UV radiation. Less ozone means more harmful UV-B radiation reaches Earth's surface.
Flashcard 19: Identify the unit used to measure the concentration of ozone.
Answer: Dobson Unit (DU). Named after ozone researcher Gordon Dobson, measures atmospheric ozone thickness.
Flashcard 20: Which protocol amendment accelerated the phase-out of CFCs?
Answer: London Amendment. This 1990 amendment strengthened CFC phase-out timelines and added new substances.
Flashcard 21: Identify the type of UV radiation most affected by ozone depletion.
Answer: UV-B radiation. This wavelength range (280-315 nm) increases most when ozone levels drop.
Flashcard 22: Identify a human activity that releases ozone-depleting substances.
Answer: Use of aerosol sprays. Aerosols historically contained CFCs as propellants, releasing them into the atmosphere.
Flashcard 23: What type of radiation does the ozone layer primarily absorb?
Answer: Ultraviolet (UV) radiation. Ozone molecules absorb UV-B and UV-C radiation, protecting life on Earth.
Flashcard 24: What is the role of polar stratospheric clouds in ozone depletion?
Answer: They provide surfaces for chlorine activation. Ice crystals convert stable chlorine compounds into reactive forms that destroy ozone.
Flashcard 25: What is the relationship between ozone depletion and cataracts?
Answer: Increased UV exposure causes cataracts. Higher UV-B levels damage eye lenses, leading to clouding and vision problems.
Flashcard 26: What is the expected timeline for full recovery of the ozone layer?
Answer: Mid-21st century. Recovery depends on continued compliance with international ozone protection agreements.
Flashcard 27: Name the international treaty aimed at reducing ozone-depleting substances.
Answer: Montreal Protocol. This 1987 agreement successfully phased out production of ozone-depleting chemicals worldwide.
Flashcard 28: How do UV rays contribute to the breakdown of CFCs?
Answer: They provide energy to release chlorine. High-energy UV photons break carbon-chlorine bonds, releasing reactive chlorine.
Flashcard 29: How does the Montreal Protocol contribute to climate protection?
Answer: Reduces greenhouse gases. CFCs are potent greenhouse gases, so eliminating them helps climate protection.
Flashcard 30: Which gas is a byproduct of CFC breakdown that also affects ozone?
Answer: Chlorine monoxide (ClO). This radical forms when chlorine reacts with ozone, continuing destructive cycles.