Lecture 1 (Week 12)

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Air Pollution Definition
Air Pollution is defined as a mixture of gases and particles that have been emitted into the atmosphere by man-made processes
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The main categories of air pollution
- Indoor air pollution
- Outdoor/ambient air pollution
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Economic dimension to who is impacted
-Disproportionately poorer households in rich countries
-More common in low and middle-income countries
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CASE STUDY - PITTSBURGH (1900s)
In 1948, a four-day temperature inversion in a nearby town of 13,000 people resulted in 20 deaths and 6,000 cases of severe respiratory disease.
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Smog Definition
A mix of smoke and fog
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CASE STUDY - LONDON SMOG
-One of the worst cases known was the Great Smog of December 1952
-4000 deaths
-Coal-burning fires
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Clean Air Acts 1956 and 1968
-Emissions of black smoke banned
-Introduced requirement for use of smokeless fuels
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Particulate matter (PM) defined
according to size
-PM10: < 10 µm in diameter
-PM2.5: < 2.5 µm in diameter
-PM1: < 1 µm in diameter
1 µm = 1 micron = 1/1000th of 1 mm
PM may be organic or inorganic
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Primary Pollutants
-Directly emitted into the air
-E.g. particulates, SO2, CO, NOx, various
hydrocarbons (HC)
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Secondary Pollutants
-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
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Anthropogenically enhanced
pollution: Sulphur dioxide (SO2)
-Description: Naturally occurring gas
-Source: Released in burning fossil fuels
-Risks: Death and injury to plants and animals. Contributes to acid rain formation
-Mitigation options: Change fuel (e.g. low-sulphur coal)
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Nitrogen dioxides (NOx)
-Description: Principally nitric oxide (NO) and nitrogen dioxide (NO2), which both contribute to smog
-Source: Nearly all NO2 is anthropogenic
- principally from vehicle and fossil fuel power stations
-Risks: NO2 contributes to acid rain
Mitigation op
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Carbon monoxide (CO)
-Description: Colourless, odourless gas
-Source: It occurs naturally or is produced when fuel is combusted at low oxygen levels
-Risks: Toxic to animals (inc. humans) at ‘low concentrations
-Mitigation options: Reducing owing to cleaner-burning engines
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Volatile Organic Compounds
-Description: Organic compounds that have a high vapour pressure at room temperature
-Source: In UK, 5% of VOCs produced by
vegetation (isoprene), 50% from transport (30% from road), 30% solvent use and 15% from industrial processes
-Risks: Carcinogenic
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Particulate matter
-Description: Particulate matter (PM) defined according to size
-Source: Asbestos, heavy metals
-Risks: Easily inhaled into lungs –embedded into lungs, arteries or carried in the blood
-Mitigation options: Improve fuels to reduce emissions at combustion,
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Lead
-Description: A heavy metal that is highly mobile. Has travelled from emissions to take up in plant tissue to entering terrestrial food chains. Transport through water to aquatic food changes
-Source: Formerly used as additive to petrol, now majority of e
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Other cards in this set

Card 2

Front

The main categories of air pollution

Back

- Indoor air pollution
- Outdoor/ambient air pollution

Card 3

Front

Economic dimension to who is impacted

Back

Preview of the front of card 3

Card 4

Front

CASE STUDY - PITTSBURGH (1900s)

Back

Preview of the front of card 4

Card 5

Front

Smog Definition

Back

Preview of the front of card 5
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