Air & Air PollutionChapter 12, Section 1: What Causes Air

Pollution?

Standards: SEV3a

What is the normal composition

of air?

78% Nitrogen

21% oxygen

1% various other

gases like

◦ Argon

◦ Carbon dioxide

◦ Water vapor

What is air pollution?

Any harmful

substance that

builds up in the air to

unhealthy levels.

Can be natural:

pollen, dust, gases

from volcanoes

Mostly human

caused: car

exhaust, coal-fired

power plants,

industrial pollution,

etc.

What is the difference between a

primary and secondary

pollutant?

Primary pollutant◦ Put directly into air by

human activities Ex: Sulfur dioxide

released from burning fossil fuel.

Secondary pollutant◦ Primary pollutants

react with other primary pollutants or water vapor to make a new substance Ex: Sulfur dioxide

mixes with water in atmosphere and causes acid rain.

What are the 5 primary air

pollutants?

1. Carbon monoxide

2. Nitrogen oxides

3. Sulfur dioxides

4. Volatile Organic

Compounds

5. Particulate Matter

1. Carbon Monoxide (CO)

Description:

◦ Odorless, colorless

◦ Poisonous

◦ From incomplete combustion of fossil fuels

Primary Source:

◦ Vehicles (cars, trucks, buses)

◦ Industrial processes

Effects:

◦ Blood can’t carry oxygen as well, feel sleepy & disoriented; can cause death

2. Nitrogen Oxides (NOx)

Description:

◦ Can be yellowish gas

◦ Forms under high temps

Primary Source:

◦ Vehicles (cars, trucks, buses)

◦ Power plants

◦ Industrial boilers

Effects:

◦ Brownish haze from smog comes from NOx

◦ Some acid precipitation

◦ Makes body vulnerable to respiratory disease & cancer

3. Sulfur dioxides (SO2)

Description:

◦ Pungent smell

Primary Source:

◦ Burning fossil fuels Power plants

Refineries

Smelters

◦ Volcanic activity

Effects:

◦ Contributes to acid rain

◦ Harm plants

◦ Irritate respiratory system

4. Volatile Organic Compounds

(VOCs)

Description:

◦ Organic chemicals

◦ Vaporize readily

◦ Form toxic fumes

Primary Source:

◦ Vehicles (cars, trucks, buses)

◦ Burning fossil fuels

Effects:

◦ Contribute to smog formation

◦ Harm plants

◦ Linked to cancer

5. Particulate Matter (PM)

Description:◦ Tiny pieces of liquid or solid

matter

Primary Source:◦ Construction, agriculture,

forestry, fires

◦ Vehicles, power plants & Industrial processes

Effects:◦ Form clouds & reduce

visibility

◦ Small pieces can be inhaled & clog respiratory system

◦ Linked to cancer

◦ Corrode metal & erode buildings

Divided into:

Fine particulate matter (PM 2.5)-

from burning fossil fuels; worst

because can be inhaled deeper

into lungs

Coarse particulate matter

(PM10)- incinerators, mining,

cement plants

How long have air pollution

problems been around? As early as 2000

years ago, people complained of “foul air”

Air pollution problems became worse around the Industrial Revolution of the 1800’s when fossils fuel usage increased and no standards existed for how much pollution could be emitted.

Weather History: The Great Smog

of 1952- London

What are two main sources of air

pollution?

1. Motor Vehicle

Emissions

2. Industrial Air

Pollution

What are Motor Vehicle

Emissions? Fumes & particulates

produced from the burning of gasoline in vehicles

1/3 of air pollution comes from gasoline burned by vehicles.

Clean Air Act-◦ regulates vehicle emissions

◦ Banned lead in gasoline-lead pollution has decreased by 90% in US.

◦ Catalytic converters clean exhaust gas

EPA says vehicles today burn fuel 35% more efficiently and with 95 % fewer emissions (except CO2) than they did 30 years ago.

What are Zero-Emissions

Vehicle (ZEV) Programs? Established in CA,

MA, ME, NY, & VT

Offer rebates, tax incentives, closer parking, use of special HOV type lanes for ZEVs

Types of ZEVs:◦ Electric cars- plug in to

recharge

◦ Hybrid cars- run on both gas and electric

◦ Methanol fuel cell cars

What are Industrial Air

Pollutants?

Any industry or power plant that burns fuel to produce energy

Power plants produce

◦ 2/3 of all SO2

emissions

◦ 1/3 of all NOx

emissions

VOCs are common type

◦ From dry cleaning fumes

What are Industrial Air

Pollutants?

Clean Air Act

requires one of the

following:

◦ Scrubbers installed in

smoke stacks to

control air pollution

Gases move through

spray of water that

dissolves the pollutant

◦ Electrostatic

Precipitators

Use static electricity to

attract particulates from

burning of fossil fuels

What is smog?

Air pollution that hangs over urban areas and reduces visibility.

Car exhaust reacts with air & sunlight to make ground level ozone.

Ozone reacts with more car exhaust to make smog.

Smog in Beijing, China (~2min)

What is a Temperature

Inversion? Circulation keeps air

pollution from reaching dangerous levels.

If a warm air mass traps a cool air mass it will trap pollution with it.

Usually common in cities surrounded on 3 sides by mountains.

Mountains trap the air.

Donora, PA (1948)- 18 people died when temperature inversion trapped SO2 & HF pollution being released from a local steel mill.

You should be able to…

Name 5 primary pollutants & give

important sources for each.

Name the 2 major sources of air

pollution in urban areas.

Describe the way in which smog

forms.

Define the term temperature inversion.

Explain how temperature inversion

traps pollutants near Earth’s surface.