Air & Air PollutionChapter 12, Section 1: What Causes Air Pollution?Standards: SEV3a

What is the normal composition of air?78% Nitrogen21% oxygen1% 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 oxides3. Sulfur dioxides4. Volatile Organic

Compounds5. Particulate

Matter

1. Carbon Monoxide (CO)Description:

◦ Odorless, colorless◦ Poisonous◦ From incomplete

combustion of fossil fuelsPrimary Source:

◦ Vehicles (cars, trucks, buses)

◦ Industrial processesEffects:

◦ 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 smellPrimary Source:

◦ Burning fossil fuels Power plants Refineries Smelters

◦ Volcanic activityEffects:

◦ 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

matterPrimary 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 lungsCoarse 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◦ Oil refineries◦ Chemical plants◦ Car repair shops

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.