Air Pollution

London Smog Crises

Cause: burnt low-grade coal with high sulfur content

Why is the atmosphere convenient to dispose wastes?

Diffuses + Disperses pollutants

• small amounts ok

• urbanization/industrialization creates too much

  • ex. London 1952

Point Source

• emissions from a discrete source

• stationary source

Fugitive Source

pollution from an open area exposed to wind processes

ex) dirt roads, wildfires, agriculture

Area source

pollution from multiple sources in a well-defined area

Mobile source

Emissions from a moving source

Primary pollutants

directly emitted to air

ex) carbon monoxide, nitrogen oxides, sulfur dioxide, aerosols, and volatile organic compounds, particulate matter

Secondary pollutants

form when primary pollutants react w atmospheric compounds

ex) ozone, acid rain, particualte matter

Sulfur dioxide (colorless/odorless gas) sources and effects?

2 sources: fossil fuels + industrial processes

4 effects: corrosion, vegetation, lung damage, acid rain

• particulate sulfate removed from atmosphere through deposition

• oxidized to form sulfuric acid

Effects of nitrogen dioxide?

1. Respiratory irritation

2. Ground-level ozone

   1. Photochemical smog

3. Acid rain

Photochemical smog

• formed when sunlight interacts with chemicals in the atmosphere - nitrogen oxides and VOCs

• secondary pollutants

• trapped near ground due to inversion

Airborne Particles

Health hazard - 85% from natural sources (fires and volcanic eruptions)

Fine particulate matter (2.5) can enter bloodstream + lungs - heart disease, lung cancer

Atmospheric inversions

hot air traps cool air near surface (air temp increases with height)

• reduced dispersion and increased concentrations of pollutants

Causes of inversion

• rapid cooling of the Earth's surface at night

• strong high-pressure systems

• geographical features like valleys

ex) cities in a “bowl” hear mountains more susceptible

Why are developing countries prone to air pollution and what protects us?

• weak environmental regulations

• high use of biomass and coal

• urbanization and industrial growth

Clean air act - emissions controls - monitoring systems protect us.

Air pollution patterns

Worst: early morning and evening - traffic

Inversions trap pollutants overnight - lift as sun warms earth every morning

Clean Air Act

Primary: protect human health

Secondary: protect environmental degredation (structures)