IBESS 6.2 Stratospheric Ozone

State the region of gas in the stratosphere that protects life on earth by filtering out most harmful ultraviolet radiation from the Sun.

• greenhouse gases

• oxygen gas layer

• troposphere

• ozone layer

The breakdown of stratospheric ozone

I. can originate from the emission of chlorofluorocarbons (CFCs).

II. is catalyzed through a free carbon (C) atom.

III. prevents UV rays from reaching the earth’s surface.

• I only

• III only

• I,&II

• I,II,& III

How do CFCs affect ozone production?

• UV radiation frees a chlorine atom in the stratosphere, which attaches to free oxygen atoms and preventing the formation ozone.

• Infrared radiation frees a chlorine atom in the stratosphere, which attaches to free oxygen atoms and preventing the formation ozone.

• UV radiation frees a fluorine atom in the stratosphere, which attaches to free oxygen atoms and preventing the formation ozone.

• Infrared radiation frees a fluorine atom in the stratosphere, which attaches to free oxygen atoms and preventing the formation ozone.

Though CFC production has been curtailed, the threat to stratospheric ozone continues because CFCs ___.

• never break down in the stratosphere

• are a secondary pollutant that continues to form from emissions produced from the combustion of fossil fuels

• CFCs are still illegally produced, sold, and traded

• persist and continue to destroy ozone for decades

Which is NOT a result of the reduction in stratospheric ozone?

• reduced photosynthetic activity

• increased skin cancer

• increased likelihood of cataracts

• increased birth defects

Which is NOT an example of an ecological consequence of reduced stratospheric ozone?

• loss of biodiversity from reduced photosynthesis in plants

• collapse of marine food webs

• increased crop yield

• reduced terrestrial biome productivity

UV rays can cause obvious short term damage, such as sunburn, as well as long term damage that accumulates with each exposure to the sun.

• True

• False

Which statement regarding the decreased level of stratospheric ozone is correct?

• Increased photosynthetic activity has been measured in the phytoplankton around Antarctica

• The largest decrease in the level of stratospheric ozone over the Arctic region occurs between January and April

• Although the Montreal Protocol led to a reduction in the use of CFCs, it will have little effect on stratospheric ozone levels in the long term

• There is no correlation between the incidence of cataracts and skin cancers and the lower level so stratospheric ozone

• The global crop yields of wheat, rice, and corn have increased since the reduction in CFC use

Location of the large whole in the ozone.

• Antarctica

• Artic

• Iceland

• Africa

Antarctica has more pronounced ozone destruction because... (choose all that apply)

• the global distillation effect moves CFCs there more than the Arctic.

• the stratospheric ice clouds are more pronounced there

• the stratospheric ice clouds are less pronounced there

• the circumpolar vortex is more pronounced there