The Kigali Amendment of 2016 to the Montreal Protocol provides for the phase down of
- A.Chlorofluorocarbons
- B.Hydrofluorocarbons
- C.Sulphur dioxide
- D.Methyl bromide
Correct answer
Explanation
The correct answer is B, hydrofluorocarbons. Hydrofluorocarbons were adopted as substitutes for chlorofluorocarbons in refrigeration and air conditioning because they do not harm the ozone layer, but they turned out to be very powerful greenhouse gases, so the Kigali Amendment of 2016 brought them under the Montreal Protocol with a schedule for reducing their use. Option A is wrong because chlorofluorocarbons were covered by the original protocol of 1987 and their production has already been phased out under it. Option C is wrong because sulphur dioxide, the main cause of acid rain, is controlled by national air quality laws and emission standards, not by this treaty. Option D is wrong because methyl bromide, used to fumigate soil, is also part of the original list of ozone depleting substances. The point being tested is that Kigali deals with a climate gas through an ozone treaty.
Read the full article: Ozone Layer and Acid Rain: Causes, Effects, Treaties
Practice Questions
View allWhich of the following statements about ozone is true?
- A.All of the options
- B.Ozone is highly reactive
- C.Ozone protects us from the harmful UV radiation of the sun
- D.Ozone is the major constituent of photochemical smog
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Each of the other three statements is correct on its own, which is exactly why the combined option is the answer.
Read the full explanation →Which of the following is a secondary pollutant?
- A.Carbon monoxide
- B.Smog
- C.Carbon dioxide
- D.Fly ash
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A primary pollutant is released directly from a source, while a secondary pollutant is formed in the atmosphere when primary pollutants react.
Read the full explanation →Which one of the following is NOT a greenhouse gas found naturally in the atmosphere?
- A.Nitrogen oxide
- B.Carbon dioxide
- C.Methane
- D.Ozone
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Nitric oxide and nitrogen dioxide, together written as nitrogen oxides, are air pollutants that come mainly from combustion in vehicles and power stations; they help form smog and acid rain but are not counted among the greenhouse gases of the natural atmosphere.
Read the full explanation →The ozone layer that protects the earth from ultraviolet radiation lies in which layer of the atmosphere?
- A.Troposphere
- B.Stratosphere
- C.Mesosphere
- D.Thermosphere
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About nine tenths of the atmosphere's ozone lies in the stratosphere, roughly fifteen to thirty five kilometres above the surface, where ultraviolet rays split oxygen molecules and the free atoms combine with other oxygen molecules to make ozone.
Read the full explanation →The thickness of the ozone column in the atmosphere is measured in which unit?
- A.Dobson unit
- B.Curie
- C.Decibel
- D.Angstrom
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The Dobson unit, named after the scientist who built the instrument for measuring atmospheric ozone, expresses how thick the ozone column would be if all of it were brought down to the surface at standard temperature and pressure; a hundred Dobson units correspond to a layer one millimetre thick.
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