Earth carbon dioxide is normally approximately 2% fraction of the air in the atmosphere. the reason carbon dioxide is considered a pollutant is a) carbon dioxide levels are much higher than ever before b) carbon dioxide absorbs infrared radiation, more co2 means more heat is trapped in the atmosphere. c) carbon dioxide breaks down the ozone layer. d) a & b

Answer is a & b.

Carbon dioxide is a main greenhouse gas which causes global warming. Carbon dioxide is considered to be a pollutant when it associated with vehicles planes, power plants, and other human activities that involve the burning of fossil fuels such petroleum ,coal and natural gas. For the last 100 years human activities have generated much carbon dioxide into the atmosphere to raise its levels higher than they have been for hundreds of thousands of years.

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