Since the Clean Air Act of 1970, emissions of most pollutants have fallen off substantially, with ...

Since the Clean Air Act of 1970, emissions of most pollutants have fallen off substantially, with _____ showing the greatest reduction.
   a. sulfur dioxide
   b. methane
   c. lead
   d. carbon dioxide
   e. carbon monoxide

Q. 2

Volcanic eruptions are an important natural source of ____.
   a. benzene
   b. ozone
   c. sulfur dioxide
   d. carbon monoxide
   e. chlorofluorocarbons

Q. 3

Once released into the atmosphere, chlorofluorocarbons remain about ____.
   a. 10-20 days
   b. 50-100 years
   c. 1-2 years
   d. 1-2 month
   e. 1000 years

Q. 4

The so-called ozone hole is observed above the ____.
   a. continent of North America
   b. equator
   c. continent of Australia
   d. continent of Antarctica
   e. continent of Asia

Q. 5



Q. 6

When chlorofluorocarbons are subjected to ultraviolet radiation, ____ is released which rapidly destroys ozone.
   a. chlorine
   b. nitrogen
   c. carbon dioxide
   d. carbon
   e. water vapour

Q. 7

The origin of the gases called oxides of nitrogen in the atmosphere begins ____.
   a. in the stratosphere
   b. in the troposphere
   c. in the mesosphere
   d. with precipitation
   e. with ice