Flashcards in Geography - Environment and Wellbeing Deck (22)
What do we mean by air quality?
Synonymous with air pollution
“Air pollution is defined as a mixture of gases and particles that have been emitted into the atmosphere by man-made processes”
Short-term and long-term effects on health, and to the natural environment
“The air quality in Scotland is generally better now than it has been at any time since before the Industrial Revolution.”
How can we compare air quality with water quality: physical, chemical and biological aspects of water?
Physical – temperature, suspended solids, radioactivity, conductivity, turbidity, colour/taste/odour
Chemical – solute load: water a universal solvent
Biological – living organisms supported in/by water
What incident regarding smog had London seen in the 1950s?
Smog – a mix of smoke and fog
Atmospheric conditions prevent the dispersion of pollution
One of the worst cases known was the Great Smog of December 1952 in London:
In some areas, people could not see their feet!
Clean Air Acts 1956 and 1968
Emissions of black smoke banned
Introduced requirement for use of smokeless fuels
What evidence has been shown regarding air quality problems?
300-year old burial ground discovered
20 000 skeletons from over 170 yrs
Analysis of human bones reveals evidence of epidemic of childhood deaths
Shift from wood-burning to coal coincident with childhood mortality
What is the structure of the earth's atmosphere?
50% of atmospheric mass is in lowest 5-6 km above surface
Total mass of atmosphere: 5.1x1018 kg
Total mass of hydrosphere: 1.4x1021 kg
What is the atmosphere made of?
Nitrogen N2 78.08
Oxygen O2 20.94
Argon Ar 0.93
Carbon dioxide CO2 0.03 (variable)
Neon Ne 0.0018
Helium He 0.0005
Ozone O3 0.00006
Hydrogen H 0.00005
Water vapour H2O variable: ppm to %
What is the difference between primary and secondary pollutants?
Primary: directly emitted into the air e.g. particulates, SO2, CO, NOx, various hydrocarbons (HC)
Secondary: produced through reactions between primary pollutants and normal atmospheric compounds
e.g. ozone forms over urban areas as a result of chemical reactions involving primary pollutants, sunlight and naturally-occurring gases
State naturally occurring pollutants.
Release of sulphur dioxide (SO2) from volcanic eruptions – volcanic smog (“vog”)
Hydrogen sulphide (H2S) emissions from geysers, hot springs, bogs & marshes
Ozone (O3) formation in lower atmosphere caused by thunderstorms/lightning
Products of windstorms and wildfires
Natural hydrocarbon (HC) seeps
Natural emissions may exceed human emissions, but not in urban areas
What is sulphur dioxide? (SO2)
Naturally occurring gas
Released in burning fossil fuels – esp. coal in power stations
Complex oxidation reactions can cause conversion into particulate form – then removed by wet or dry deposition
Death and injury to plants and animals, inc. to the lungs
Contributes to acid rain formation
What is nitrogen oxide? (NOx)
Principally nitric oxide (NO) and nitrogen dioxide (NO2)
Both contribute to smog
NO2 contributes to acid rain
May be converted by complex reactions into NO32- ion within water droplets
Nearly all NO2 is anthropogenic – principally from vehicle and fossil fuel power stations
Human effects – irritation of eyes, nose, throat, lungs; increased susceptibility to viral infections.
May suppress plant growth, but fertilise soil in nitrite form.
What is carbon monoxide? (CO)
Toxic to animals (inc. humans) at ‘low concentrations’
Toxicity arises from natural attraction between CO and haemoglobin in blood (250x greater attraction than to O2)
High risk of asphyxia when incomplete combustion occurs CO monitors (CO: “silent killer”)
In UK each year, 50 people die and 4000 hospitalised due to CO poisoning
1 in 10 thought to have suffered CO poisoning
Global emissions principally through vehicle tailpipes
Reducing owing to cleaner-burning engines, despite growth in vehicle numbers
Name characteristics of the ozone (O3) and other photochemical oxidants.
Originates with burning fossil fuels (inc vehicles exhausts), creating NO2
Formed by effects of sunlight on NO2
Ozone is unstable, so available to support burning/oxidation not allowed by O2
Because of its chemical activity, O3 very harmful to living things, but in the stratosphere, it helps protect Earth from solar UV rays
Causes damage to animals, plants, rubber, paint, textiles…
What are volatile organic compounds?
Organic compounds used as solvents in industrial processes, e.g. dry cleaning, de-greasing
Hydrocarbons include one group of VOCs
Thousands of HC compounds exist – inc. natural gas (methane – CH4), butane (C4H10) and propane (C3H8)
Some VOCs found in urban air cause photochemical smog
Many are directly toxic to plants and animals – or may form other harmful compounds through chemical reactions in the atmosphere
What is particulate matter?
Heavy metals (As, Cu, Pb, Zn…)
Some particulates are invisible to the eye – below ~ 7 µm (human hair is 60-150 µm in diameter)
Easily inhaled into lungs – embedded into lungs, arteries or carried in blood
Particulate air pollution estimated to cause 60 000 premature deaths annually in USA
What is lead?
Formerly used as additive to petrol
Still used in batteries
Widely spread with vehicle exhausts into soils take-up by plants terrestrial food chains
Transport in waters to the rivers and oceans aquatic food chains
Found in Greenland ice cores, i.e. worldwide distribution
Use in petrol discontinued in UK in 1999
Industrial emissions remain
Impact on brain function
What have insights from medical science shown us about air quality?
Volunteer cyclists exposed to ambient traffic pollution for 1 hour: significant impact on relaxation of arteries after exercise
Mice exposed to Western diet for 8 weeks and ambient pollution levels for 4 weeks – evidence of PM damage to lining of arteries
What is meant by "The Global Commons"?
“The ‘Global Commons’ refers to resource domains or areas that lie outside of the political reach of any one nation State” – United Nations Environment Programme
Origin of term ‘commons’
International law identifies four global commons:
Open access to all without legal restriction. Threats to sustainability? What are the threats to each of these commons?
What is the 1995 Environment Act?
Required the Secretary of State for Environment to prepare a national air quality strategy
Provided for the establishment of Air Quality Management Areas
Strategy developed by devolved administrations and Defra
Latest version of joint strategy issued 2007
Superseded in Scotland by ‘Clean Air for Scotland’ (2015)
What is covered in Section 83(1) of the 1995 Environment Act?
Local Authorities have a duty to designate any relevant areas where the air quality objectives are not (or are unlikely to be) being met as Air Quality Management Areas (AQMAs)
Following the declaration of an AQMA, the local authority is required to develop and implement a plan (Air Quality Action Plan) to improve air quality in that area.
Where are the 6 Air Quality Management Areas in Edinburgh?
St John’s Road
Great Junction Street
What are air quality objectives?
Annual average <40 µg/m3
No more than 18 exceedances of 200 µg/m3
Annual average <18 µg/m3
No more than 7 exceedances per year of 50 µg/m3