Lecture 4: Plant Responses To Air Pollutants Flashcards
Pollutants
A chemical that is in the wrong place at the wrong concentration and that has the potential to cause damage to the environment.
Air pollutants
Chemicals that are emitted to the atmosphere which adversely affect physical and biological systems.
Two types of air pollutants
- particulate air pollutants
- gaseous air pollutants
Two types of gaseous air pollutants
Primary and secondary pollutants
Primary pollutants
Chemicals that are emitted directly into the atmosphere (in the form of which it will have an adverse effect)
Two primary pollutants
- Nitrogen monoxide (NO)
* Sulphur dioxide (SO2)
Secondary pollutants
Chemicals that are formed by the reactions in the atmosphere between primary pollutants and other agents (eg: light)
Two secondary pollutants
- Nitrogen dioxide (NO2)
* Ozone (O3)
Orgins of gaseous pollutants
2
Natural and anthropogenic emissions
Natural emissions of gaseous pollutants
Volcanoes and swamps
Anthropogenic emissions of gaseous pollutants
Domestic and industrial sources
VOC
Volatile organic compounds
Two types of depositiion of air pollutants
Wet and dry deposition
Dry deposition of SO2 and NOx can cause
2
Inhibition of photosynthesis and inhibition of growth
Why is inhibition of photosynthesis by dry deposition of SO2 and NOx greater in high light?
More stomata are open in high light so more pollutants enter the plant.
Which reaction (s) in photosynthesis are affected by dry deposition of SO2 and NOx
Both light dependent and light independent reactions
Wet deposition of SO2 and NOx causes
Acid rain
Where is ‘good’ ozone found?
And what does it do?
The stratosphere - upper atmosphere
It filters out UV in solar radiation
Where is ’bad’ ozone found?
And how is it formed?
Foudn in the troposphere - lower atmosphere.
Formed by complex photochemical rections between pollutants.
Global warming
Global warming: an average increase in the Earth’s temperature that in turn causes changes in climate.
Greenhouse effect
Greenhouse effects: trapping of IR radiation, produced when solar radiation is absorbed and then partially re-emitted, by the Earth’s atmosphere
Greenhouse gases
Greenhouse gases: any gas that absorbs IR radiation in the atmosphere.
Climate change
Climate change: changes in climate resulting from global warming.
Is global warming an essential process?
The greenhouse effect is a natural process without which the Earth’s temperature would be -18 degrees C
