Chapter 15Section 4: The Air We Breathe

Mrs. Mannel

Earth Science

Air Quality

Even “clean” air is polluted from natural sources

Pollutants such as dust, sea salt, volcanic ash, smoke from forest fires, pollen, and swamp gas contaminate the air we breath

Air pollution from humans is most common in cities

Types of Air Pollution

Typically described as Primary or Secondary pollutants

Primary Pollutants are put directly into the air by human or natural activity (exhaust, volcanoes)

Secondary Pollutants form from chemical reactions that occur when primary pollutants come into contact with other primary pollutants (ozone, smog)

Sources of Human-Caused Air Pollution

Cars contribute 60% of air pollution in the U.S.

Industrial and electrical power plants burn fossil fuels which causes large amounts of oxides to be released into the air

The Air Pollution Problem

Air pollution can be a local problem (smog) and a global problem

It is a global problem when winds transfer local pollution from one place to another

Acid Precipitation

Precipitation from air pollution that contains acids is called Acid Precipitation

Sulfur and Nitric Oxides produced from the burning of fossil fuels mix with water droplets in the atmosphere

Acid precipitation can kill fish and trees by making their environment too acidic to live

The Ozone Hole

In the 1970s scientists discovered that certain chemicals released into the atmosphere react with ozone

This reaction caused a breakdown of the ozone layer which would allow harmful UV rays to reach the Earth’s surface

Effects on Human Health

Children, elderly people and people with allergies, lung problems, and heart problems are very vulnerable to the effects of air pollution

Air pollution can cause dizziness, burning and itchy eyes, trouble breathing, sore throat, lung cancer, chest pains and increased colds

Cleaning Up Our Act

The Clean Air Act passed in 1970 is a law that gives the EPA the authority to control the amount of air pollutants that can be released from any source

They also check for air quality and set requirements for car manufacturers and factories