Air Pollution

what is air pollution?

• Particulate matter– Very small particles of fuel that has been burned.

Ex, diesel smoke

• Noxious gases– Chemicals that can cause harm directly, or react

with other chemicals to do damage.

Smog demo?

smog

• What is it?– a hazy mixture of pollutants in the air, primarily

made up of ground-level ozone.• What causes it?– When sunlight causes volatile organic compounds

(VOCs) to react with nitrous oxide. This produces ozone.

Temp. Inversion

Temperature inversion

• occurs when air close to the earth is cooler than the air above it. (hot on top, cold on bottom)

• Under these conditions, pollution cannot rise and be dispersed. It is trapped on the surface, where humans breathe it.

Examples:

Acid rain

Acid rain

• When a pollutant, such as sulfuric acid combines with droplets of water in the air, the water (or snow) can become acidified .

Effects of acid rain

• Acid rain erodes stones and statues, harms plant life, and can acidify lakes and streams.

Atmosphere Composition

Atmosphere composition

• Troposphere – 0-15km . This is the air we live in and breathe; weather occurs here.

• It’s name comes from Greek ‘trope’ meaning ‘to turn over.’

Atmosphere composition

• Stratosphere – 15-50km • Ozone layer is here;

absorbs radiation. • No weather, so airplanes

fly in the stratosphere.

Atmosphere composition

• Mesosphere – 50-85km

• Air thins out; gets very cold. Coldest place on earth at -150 F

• Meteors burn up here (“shooting stars”)

Atmosphere composition

• Thermosphere – 85-500 (can vary 350 to 800km)

• Almost no air here; expands and contracts as the sun heats it

• low gravity; space shuttle and ISS orbit here.

• auroras

Atmosphere composition

• N - 78%• O – 20%• Ar – 1%• CO2 - .05% a little bit can have a big effect!• Other - .05% including Neon, Helium, Methane,

Krypton

• How much does the atmosphere weigh?– Approx. 5.5 quadrillion tons!

Class Atmosphere(see slide notes)

Greenhouse Effect

Greenhouse effect

• What is it?– When gases (notably CO2) act like a blanket to

hold heat close to the earth. • Why do we care?– Changes of even a few degrees can have big

effects. Ex, raising sea levels,

2 meters

Greenhouse debate

• Watch two debates• Write down arguments in favor of each side.

Ozone

Ozone depletion

• What is ozone?

• chlorofluorocarbons (CFC's) come from aerosol cans, cooling systems and refrigerator equipment.

• CFCs react with ozone molecules, creating "holes” and allowing radiation to reach the earth.

Health effects

Health effectsof atmospheric pollution

• short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia.

• Long-term includes chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys.