6 Flashcards
Composition of the Atmosphere
Nitrogen - 78%
Oxygen - 21%
CO2, Ar, H2O(g), O3 - 1%
Stratosphere
10-50km
Troposphere
less than 10km
Greenhouse Effect
GHG present in the atmosphere, reflect/trap/absorb/scatters radiation leaving the planet’s surface back towards it/not out to space. This keeps energy near the surface of the Earth which helps to maintain the temperature.
Ozone
O3 molecules. Stratospheric ozone blocks incoming UV radiation.
Ozone Layer
In the stratosphere. Dynamic equilibrium as ozone is made from o atoms then turns into o atoms, when UV radiation is absorbed. Ozone layer absorbs 99% of UV-C radiation (most damaging as highest energy).
Effects of UV Radiation Cons
Genetic mutation
Damage to living tissue
Cataract formation in eyes
Skin cancers
Suppression of the immune system
damage to photosynthetic organisms (phytoplankton)
Damage consumers of ^^^, zooplankton
Effects of UV Radiation Pros
UV radiation stimulates production of Vitamin D, (rickets from deficiency)
steriliser, kills bacteria, air and water purifier
industrial use - lasers, viewing old scripts, forensic analysis, lighting
Ozone Hole
Above Antartica due to wind and Earth’s rotation
ODS
CFCs, HCFCs, Halons, Methyl Bromide, Nitrogen Oxides
Propellants in aerosols, pesticides, flame retardants, refrigerants.
Significance of Montreal Protocol
Best example of international cooperation on env. issue
Example of precautionary principle in science-based decision making
Many experts researching common thing
First to recognise countries could phase out at different times
First where regulations were carefully monitored
Primary Pollutants
Emitted directly from a process. Natural (volcano) or Anthropogenic (FF).
Combustion of FF;
CO
CO2
HCO unburned
NOx’s
SO4
Particulate matter
Secondary Pollutants
When PP undergo reactions with other chemicals. Maybe be a photochemical reaction in the presence of sunlight.
Tropospheric Ozone
Particulates
PAN (peroxyacetyl nitrate)
Tropospheric Ozone
10% of all ozone.
Global warming potential 2000 times CO2
Formation of Tropospheric Ozone
Combustion of FF
nitric oxide + oxygen - nitrogen dioxide - (w sunlight) nitric oxide and oxygen atom + oxygen molecule - ozone
Effects of Tropospheric Ozone
Oxidising agent
toxic
damages plants by degrading chlorophyll
damage to humans (breathing difficulties, more susceptible to infection, Eye, nose, throat irritation.
Particulates
Burning organic material makes the,.
Respiratory filters can not filter them out (cancer, asthma, death)
Carcinogenic
Leaves covered, less productivity as less sunlight hitting leaves.
Photochemical Smog
NO2 and O3, peak just after noon. LA-type smog. Local topography, climate, population density, fossil fuel use affect occurrence.
Thermal Inversion
When warm air traps cool air. This can trap smog.
Weather and Photochemical Smog
Peak when hot and no wind.
Acid Deposition
Acid coming down from the air.
Wet - Rain or Snow
Dry - Ash/dry things
Sources of Acid Deposition
Volcanic Eruptions - SO2
Lightning - NOx’s
FF - SO2 from sulphur containing coal
- NOx’s from high heat, O and N in air react.
These form secondary pollutants (+ water or oxygen) which are very soluble in water.
Acid Deposition and Coniferous Forests
Loss of chlorophyl - yellowing.
Lesions on leaves -wax cuticles thin
Reduce growth, allowing nutrients to be leached out and washed away.
Pathogens and insects can then gain entry.
Root microbes killed, reducing availability of nutrients, less growth.
Soils cannot as easily hold nutrients.
Aluminium ions from soils damage roots.
Trees weaken and may die.
Acid Deposition and Water Systems
Increased acidity of soil makes aluminium more soluble so it washes out into waterways. Aluminium inhibits fishes ability to regulate oxygen and salt content, lose salt. Solid can form on gills leading to suffocation. Low then high concentrations respectively.
Acid Deposition and Lichens
Lichens are indicator species. Few species can survive near emission point. As you move away, more species can survive/are present.
Acid Deposition and Soil
Reduces ability to hold nutrients which are washed out.
Nitrogen fixing bacteria are inhibited.
Acid Deposition and Buildings
Limestone dissolves.
Acid Deposition and Peat Bogs
produce 40% less methane as bacteria that eat sulphates outcompete bacteria that produce methane.
Acid Deposition and Human Health
Dry deposition causes lung diseases such as asthma and bronchitis. Premature deaths may result.
Regional Effect of Acid Deposition
Dry deposition occurs close to emission point.
Wet deposition occurs further away.
Areas downwind are most affected.
How to Reduce Effects of Acid Deposition
Liming Lakes.
Reducing Emissions.
Pre-combustion Techniques.
End of Pipe Measures.
Liming Lakes
1950s, many Scandinavian lakes faced loss of species due to increased acidity.
1990, 400 lakes were lifeless.
80’s Sweden added limestone powder to lakes and rivers.
pH dropped but then rose quickly, treats symptoms not cause.
Biodiversity was not restored quickly.
Unbalanced nutrient levels (only calcium)
Reducing Emissions
Reduce combustion of FF reduced emission of SO2 and NOx’s.
Through; reducing need for electricity, need for cars, or switching to renewable energy.
Pre-combustion Techniques
Remove sulphur from fuel.
Use it for; chemical industry, gypsum for construction, SO2 for sulphuric acid.
End of pipe Measures
Removes SO2 and NOx’s from waste gases.
Waste gas scrubbers in electricity plants. - SO2
Catalytic converter. - NOx’s
Incoming Solar Radiation
UV, Infrared and Visible.
Infrared absorbed by the atmosphere.
UV absorbed by Ozone.
GHG Examples
CO2, CH4, Water Vapour
Kigali
2019, Phase out HFCs from 2019.
