Air Pollution

The Atmosphere as a Resource

Atmospheric composition:

Nitrogen = 78%

Oxygen = 21%

Argon = 0.93%

Carbon dioxide = 0.04%

The Atmosphere as a Resource

1. Name the 4 major gaseous components of the earth’s atmosphere.

2. Describe 2 ecosystem services that the atmosphere provides.

Air Pollution

What do you know?

1. What is outdoor air pollution?

2. What do you think causes outdoor air pollution?

3. Where does air pollution come from?

4. Have you ever seen air pollution? How do you know?

5. Is air pollution a solid, liquid or a gas?

6. Do you think humans are affected by air pollution? How?

Air Pollution

7. What else do you think might be affected by air pollution?

8. How do we get rid of air pollution?

9. Have you heard of ozone? Is it good or bad? Explain.

10.Have you heard about particle pollution before?

11.Do you think particles floating in the air affect humans? How?

12.How do particles get into the air?

Types of Air Pollution

Air Pollution – various substances added to the atmosphere by natural events and human activities in high enough concentrations to cause harm to humans, other organisms, or materials

Primary air pollutant – a substance emitted directly to the atmosphere

Secondary Air Pollutant – a substance formed in the atmosphere as a result of reactions involving primary pollutants

Types and Sources of Air Pollution

Primary and Secondary Air Pollutants

Types and Sources of Air Pollution

Major Classes of Air Pollutants

• Particulate matter

• Nitrogen oxides

• Sulfur oxides

• Carbon oxides

• Hydrocarbons

• Ozone

• Lead

Ozone damage

Types and Sources of Air Pollution

Major Air Pollutants

Types and Sources of Air Pollution

Learning Objective:

1. Describe the difference between a primary and secondary air pollutant and give examples of each.

Types of Air Pollution

Particulate Matter – solid and liquids suspended in the atmosphere.

• Soil, Soot, lead, asbestos, sea salt, sulfuric acid droplets

• Reduces visibility• Corrodes structures• Leaves residue on

surfaces• Can absorb other toxic

substances

Types of Air PollutionNitrogen oxides- NO, NO2, N2O

• Produced by the reaction at high temperatures between N2 and O2

• Inhibit plant growth

• Aggravate respiratory conditions

• Involved in the production of photochemical smog

• N2O is a greenhouse gas and is involved in ozone depletion

• Corrode metals and textiles

Types of Pollution

Sulfur oxides – SO2, SO3

• formed mainly when sulfur containing fuels are burned (mainly coal)

• Dissolve in water to form sulfuric acid (acid rain), which damages plants and structures

• Damage plants

• Respiratory irritants

Types of Pollution

Carbon Monoxide – CO

• Produced by the incomplete combustion of hydrocarbons

• Poisonous gas

Types of Pollution

Hydrocarbons-compounds containing H and C

• Wide variety of compounds

• Involved in the production of photochemical smog.

• Some are toxic (respiratory irritants, cancerous)

• Some are involved in ozone depletion

• Methane (CH4) is a potent greenhouse gas.

Types of Pollution

Ozone – O3

• Essential component of the stratosphere that blocks UV light waves from the sun

• Harmful component of photochemical smog in the troposphere.

• A secondary pollutant formed by reactions between nitrogen oxides and hydrocarbons, initiated by sunlight

• Reduces visibility and causes health problems; damage to plants

Effects of Air Pollution

• Damages organisms

• Reduced visibility

• Corrodes materials

• Especially harmful to the respiratory systems of humans

• Reduction in crop productivity

• Leads to acid deposition

• Global climate change

• Stratospheric ozone depletion

Effects of Air PollutionAir Pollution and Human Health

Air Toxics – a variety of hazardous air pollutants; it is estimated that 360 out of 1 million Americans die of cancer every year as a result of air toxics.

Effects of Air Pollution

Effects of air pollution on children:

• Air pollution can restrict lung development in children making them more susceptible to respiratory and heart problems later in life.

• Children have a higher metabolic rate, meaning they breathe in more air than adults.

Controlling Air Pollution in the United States

Clean Air ActEmissions in the US, 1970 vs. 2000

Controlling Air Pollution

• Energy efficiency and conservation are important• Smokestacks are equipped with electrostatic

precipitators, scrubbers, filters, etc. to remove particulates, sulfur oxides, and nitrogen oxides

• Controlling the fuel/air ratio and lowering combustion temperatures leads to the production of less nitrogen oxides

• Modifications to furnaces and combustion engines to provide more complete combustion eliminates carbon monoxide and hydrocarbon emissions.

Controlling Air Pollution in the United States

Controlling Air Pollutants

Turned ON

Electrostatic precipitator

Turned OFF

Controlling Air Pollution in the United States

Controlling Air Pollutants

Turned ON

Electrostatic precipitator

Turned OFF

Controlling Air Pollution

Clean Air Act

• passed in 1970; amended in 1977 and 1990

• Administered by the EPA

• States pass laws which must be as stringent as the federal law

• Focuses on six air pollutants (lead, particulates, sulfur dioxide, carbon monoxide, nitrogen oxides, ozone)

Controlling Air Pollution in the United States

US Urban Areas with Worst Air Quality, 2002

Controlling Air Pollution

Clean Air Act

• Areas which do not meet regulatory requirements for the six pollutants are designated as nonattainment areas

• 1977 and 1990 amendments required stricter controls on automobile emissions.

• 1990 amendments also focused on regulation of air toxics; required a 90 % reduction in emissions of 189 toxic chemicals