DOL 8/12-8/13

What characteristic(s) of CFCs and HCFCs make them more likely to reach the stratosphere than most other compounds containing chlorine?

• They do not dissolve in water or easily break down in the atmosphere.

• They are lighter than other chlorine compounds, making it easier for them to reach the stratosphere when released.

• They are stored under pressure, causing them to jet upward when released.

• They are attracted to ultraviolet radiation.

Which of the following gases help form the earth's protective shield?

• Methane

• Radon

• Stratospheric Ozone

• Carbon Dioxide

From which of the following does the ozone layer protect the earth?

• Nuclear radiation from the Van Allen belt

• Gamma radiation from the sun

• Ultraviolet radiation from the sun

• Infrared radiation from the sun

What is the strongest evidence that HCFCs are in the stratosphere?

• Chemical reactions predict there should be HCFCs in the upper atmosphere.

• Measurement of chlorine in air samples from the lower atmosphere.

• Measurement of HCFCs in air samples from the stratosphere.

• Satellite measurements of light passing through the atmosphere.

What evidence demonstrates that chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes?

• The rise in the amount of chlorine measured in the stratosphere matches the rise in the amount of fluorine, which has different natural sources than chlorine, over the same period.

• The rise in the amount of chlorine measured in the stratosphere matches the rise in ozone-depleting substance missions over the same period.

• Samples of air taken from the stratosphere over erupting volcanoes show that volcanoes contribute a small quantity of chlorine to the stratosphere compared to CFCs and HCFCs.

• All of the listed reasons.