Urban Air Pollution

Get out Homework!

• Out on your desk have the following: • Wind Review Worksheet • Stamp sheet• Pencil/pen• Red and blue

PUT EVERYTHING ELSE AWAY!

Santiago, Chile

Mexico City, Mexico

Salt Lake City, Utah

Denver

Los Angeles

What is an Inversion?• Second Layer:– Clear, breathable, clean air

• Surface Layer:– Dirty, brown, polluted air

Boundary

Sources of Pollution

• Cars• Factories• Ships• Airplanes• Tractors• Fires• Cooking

Density

• Density • Amount of mass in a given volume

Density = 5 circles per cube

Density

• Density • Amount of mass in a given volume

Density = 11 circles per cube

Temperature Affects Density

Density = 6 circles per cube2 circles per cube

Temperature Affects Density

Density = 3 circles per cube10 circles per cube

Which rises and which sinks?

Density =5 circles per balloon

Density =2 circles per balloon

Which rises and which sinks?

Density =3 circles per cube

Density =7 circles per cube

Normal Atmosphere

WARM

COOLCOLD

• Normal atmosphere

• Air can rise and mix freely throughout the entire troposphere

Inversion Atmosphere

COLD

WARMCOOL

• Inversion • Air is trapped in the bottom layer of cold air

Inversion Atmosphere

WARMCOOL

• Mountains • Prevent air from leaving the city

COLD

Define– Normal Atmosphere :

– Inversion Atmosphere :

Air can mix freely through the entire troposphere

Air is trapped in the bottom layer of cold air

Normal AtmosphereInversion Atmosphere

Types of Inversions

• Radiation inversions– At night or during winter, the surface cools faster

than the air above it

HOT

HOT

COLD

WARM

Types of Inversions

• Sea breeze inversions– Sea breeze injects cold air below warm air

HOT

HOT

COLD

How to break an Inversion

• Sunlight– Warms the surface faster than the air above,

eliminating the inversion.

COLD

COOL

HOT

WARM

How to break an Inversion

• Rain– Makes the atmosphere the same temperature and

cleans pollution.

COOL

WARMCOOL

How to break an inversion

• Winds– Mix the atmosphere, eliminating inversion.

COLD

HOTWARM

WARM

Discuss– What is an inversion?– How does it form?– How do inversions break?

Mumbai, India

Madrid, Spain

Air Pollution Negative Impacts

• Decrease Visibility• Make Bodies of water more Acidic• Affect our health – Irritate lungs– Aggravate asthma– Lead to nonfatal heart attacks in elderly– Premature death in people with heart or lung

disease

• Describe how an inversion forms

• During the winter surface cools faster than air above it

• Sea breeze injects cold air in the surface

Types of Inversions

• Subsidence inversions– Sinking air from high pressure compresses and

warms air high above surface

COOL

WARM

Convection Demonstration