ESS Topic 6 Flashcards
atmosphere system
dynamic - inputs, outputs, storages, flows
heat and pollutants carried by air currents
greenhouse effect
caused by gases in atmosphere reducing heat losses by radiation back in space trapping heat energy reflected from Earth’s surface and re-radiate it
maintains suitable temperatures for living systems
greenhouse gases
absorb heat and re-emits it as heat energy back to Earth
main ones are - water vapour, carbon dioxide and methane
ozone
found in 2 layers of atmosphere
good in stratosphere
bad in trophosphere
ozone layer
lower stratosphere
made from oxygen and is continuously converted back into o2
absorbs UV radiation - crucial for life on land
UV radiation
UV C - highest energy and shortest wave length (most harmful
UV B
UV - A longer wavelength (lowest energy) relatively harmless
damaging effects of UV radiation
genetic mutation
damage to living tissue
cataract formation in eyes
skin cancers
suppression of immune system
damage to photosynthetic organisms - phytoplankton
damage to consumers of photosynthetic organisms - zooplankton
beneficial effects of UV radiation
stimulates production of vitamin D in animals
can be used to treat skin diseases - psoriasis and vitiligo
used as steriliser - kills pathogenic bacteria
can be an air and water purifier
industrial uses - lasers, viewing old scripts, forensic analysis, lighting
Ozone Depleting substances
chlorofluorocarbons (CFCs) - most important, releases chlorine atoms, used in spray cans, plastic foam expanders, refrigerants
Hydrochlorofluorocarbons (HCFCs) - used as replacement for CFCs, releases chlorine atoms but shorter influence
Halons - fire extinguishers, releases bromine atoms
Methyl Bromide - pesticide, releases bromine atoms
Nitrogen Oxides - used in bacterial breakdown of nitrates in soil (intensive farming), converted into NO which reacts with oxygen
Action of ODS
chlorine atoms react with ozone causing its destruction - also reacts with oxygen preventing ozone formation
CFCs may remain in atmosphere for up to 100 years
replace - reducing ODS
replace gas-blown plastics
replace CFCs with CO2 prone or air as propellant
replace aerosols with pump action sprays
replace methyl bromide pesticides
regulate - reducing ODS
recover and recycle CFCs from refrigerators and ACs
legislate to have fridges returned to manufacturer and coolants removed and stored
capture CFCs from scrap AC units
restore - reducing ODS
add ozone or remove chlorine from stratosphere
primary urban air pollution
carbon monoxide - incomplete combustion of fossil fuels
carbon dioxide
unburned hydrocarbon
nitrogen oxides
sulphur dioxide
particulate matter
building sites and forest fires
Secondary urban air pollution
formed when primary pollutants undergo a variety of reactions with other chemicals in atmosphere - may be photochemical in presence of sunlight
e.g. tropospheric ozone, particulates produced from gaseous primary pollutants, peroxyacteyl nitrate (PAn
Tropospheric Ozone
10% of ozone in troposphere
ozone is GHG with 2000 GWP than CO2
effects of tropospheric ozone
damage to plants - degrades chlorophyll so photosynthesis is reduced
damage to humans - reduce action of lungs
damage to materials and products
dangers of particulates
enter human system causing asthma, lung cancer, respiratory problems and death
cancer causing
crops covered in it can reduce productivity - less sunlight reaches leaf
photochemical smog
complex mixture of hundreds of primary and secondary pollutants
formed when ozone, nitrogen oxides and gaseous hydrocarbons from vehicle exhaust interacting with strong sunlight
occurrence of photochemical smog governed by
local topography
climate
population density
fossil fuel use
common in large cities that are low lying (valleys) on calm days
thermal inversion
increases photochemical smog
warm days - polluted air prevents air rising and traps pollution on ground level
types acid deposition
wet - rain
dry - coming down in ash or dry particles
natural source of acid deposition pollutants
volcanic eruptions - producing sulphur dioxide
lightning causing nitrogen oxides
causes of acid deposition
pollutants increase acidification
rain already slightly acidic due to presence of CO2 in atmosphere
