Atmospheric Pollution Flashcards
SMOKE
What is it?
-suspended particles from incomplete combustion
SMOKE
source of smoke
-Fireplace
-cigarettes
-diesel engines
-factory’s
-wild forest fires
SMOKE
toxic chemicals found in smoke
-heavy metals: aluminium, sulphur, lead
SMOKE
effects of smoke
-humans: respiratory problems, eye problems, bronchitis, lung cancer, COPD, carcinogenic (heavy metals)
-plants: particulates settle on leafs, block light, reduce photosynthesis, heavy metals toxic to plants
-non living organisms: particulates adhere to buildings, removal is difficult and expensive, produce more particulates, if in contact with other metals like sulphur can be corrosive
-climate/atmosphere: blocks our sun rays reaching earth, increases albedo due to particulates being flat reflect light
SMOG
what is it?
-smoke and fog
-airborne particles and ground level ozone, from car exhaust, coal power stations, paint, cleaning solvents
SMOG
how’s it formed?
-when sunlight hits chemicals in atmosphere, smog is formed.
-fog is formed when moist air is cooled and then gets lots of water droplets
-smog is formed when particulates are involved
-smoke in fog is held lower in the atmosphere, more likely to be inhaled
SMOG
what increases smog?
-temperature inversion
-this is when overcoming air becomes warmer as the altitude increases
-this is created when:
-clear skys at night (no clouds)
-low winds (keeps cold air at low ground)
-in valley (traps)
-mist/fog in day (increases albedo)
Temperature inversion
-overcoming air is warmer than air below
-trapping pollutants
-caused by smog
PHOTOCHEMICAL SMOG
what is it?
reactions with chemicals such as NOXs with light
PHOTOCHEMICAL SMOG
pollutants involved with the formation
-NOXs from vehicle engines
-VOCs (hydrocarbon gases from petrol stations)
-O3 in the troposphere
PHOTOCHEMICAL SMOG
chemical reactions
-NO2 + UV light
(UV light breaks bonds in NO2)
-forming NO + O
-O + O2 forms O3
-NO releases monoatomic oxygen (O)
which is reactive, unstable and reacts with other oxygens producing O2 and O3
-HC floating around near petrol stations
-PANS is formed: much bigger impact on respiratory problems then the other pollutants on their own
PHOTOCHEMICAL SMOG
what other conditions stop pollutants from dispersing making them more dangerous?
-temperature inversion
-need to be in a low lying area
-cold temps
-low winds
-clear skys
PHOTOCHEMICAL SMOG
How can we reduce chances of photochemical fog?
-vegetation/green barriers to absorb NO2
-fuel stations use activated carbon stations (absorb NOXs)
-low emission zones, can be fined for taking a car into a zone of NOXs
-provided insensitive for electric vehicles (cooler engine don’t produce NOXs)
-oxidise hydrocarbons producing CO2 and H2O
-catalytic converters
Acid precipitation
gases that cause acid rain
-SOXs
sulphur from combustion of coal, oxidised and turns into SOXs
reacts with water and produces acid rain H2SO4
-NOXs
-ozone
-hydrocarbons
Acid precipitation
direct effects on non living
-corrode buildings (limestone as alkali)
-any building that constrains limestone (concrete and cement, brick, metal work, pipelines, bridges, girders, pile ons)
Acid precipitation
direct effects on living organsims
-lichen are very susceptible to acidic conditions
-denatures cells
-kills plants
-pollutes water sources
-once pH of 5 fish eggs can’t hatch, also outside some organisms range of tolerance
-breakdown of outer layer of organisms- root hair on plants, damages stomata
-breaks down anything with exoskeleton as susceptible (cray dish, ants, crabs, corals)
Acid precipitation
in-direct effects on living organisms-soil
-metals go into solution more easily in acidic conditions
-some metals are essential for plants: copper, aluminium, when leached away plants don’t absorb these, end up absorbing toxic metals
Acid precipitation
environmental factors and there affect on severity of acid rain
-soil pH
increase in pH less impact of acid rain- areas where bedrock is limestone
-fog
acid rain is not landing like rain, it’s hanging in the air and in contact with everything for longer
-snow/ice
acid locked up as sold, but then when melted all acid is released, causing large decrease in pH
Reducing acid precipitation
reducing SOx by natural gas desulphurisation
Removal of sulphur before combustion:
-natural gas desulphurisation
-sulphur in form of hydrogen sulphide
-reacts with amine solution (alkali)
-sulphur left behind in solution and removed form gas
Reducing acid rain
reducing SOx by crude oils desulphurisation
Crude oil desulphurisation (before combustion)
-sulphur in form of sulphur
-sulphur compiles found in crude oil
-can remove sulphur via distillation
Reducing acid rain
reducing SOx by coal desulphurisation
coal desulphurisation (before combustion)
-sulphur in form of iron pyrites in coal
-crush coal and flow water over top of coal dust
-denser material left behind which is iron pyrites
Reducing acid rain
reducing SOx by dry flue - gas desulphurisation
dry flue (removal after combustion)
-pass emissions through crushed limestone
-sulphur left behind with calcium bricks
-used to make plaster board
Reducing acid rain
reducing SOx by using wet flue - gas desulphurisation
-bubble emissions through alkali solution (sodium sulphite)
-produces sodium hydrogen sulphide
-used to neutralise alkali soils
Reducing acid rain
reducing NOx using low temperature combustion
-high temperature engines draw air that contains nitrogen
-nitrogen binder with triple bond, hot engine breaks bond
-reduced temp of engine by increasing SA for combustion so heat decreases
