Daily EQ:

• What is the ozone layer, where do you find it, and why is it important?

The Ozone layer… what is it? Where is it? What does it do??

Environmental ScienceDec 2011

Key concepts: Analyze the difference in the two global warming theories. Describe the factors affecting the changes in the Earth’s climate.

Unit EQ: How does the cycle of cooling and warming in the atmosphere affect the Earth and it’s inhabitants.

What factors cause these changes?

Atmosphere Milakovitch Theory

Human Caused Theory Ozone

Daily EQ: How does the composition of the atmosphere affect the temperature of the Earth?

Daily EQ: How does the Earth cool and heat up naturally?

Troposphere

Thermosphere

Stratosphere

Mesosphere

Exosphere

Greenhouse Effect

Greenhouse gases

Daily EQ: How are human actions causing change in atmospheric temperatures

Ice cores

Daily EQ:What is the ozone layer, where do you find it, and why is it important?

Ozone, tropospheric ozone, stratospheric ozone, UV radiation, smog,

Ozone is…

• (O3) composed of three oxygen atoms• is a highly reactive gas.

What is the ozone layer?

• "The ozone layer" refers to the ozone within stratosphere, where over 90% of the earth's ozone resides.

• Ozone is an irritating, corrosive, colorless gas with a smell something like burning electrical wiring.

What is the ozone layer?

• Ozone occurs in two layers of the atmosphere. The layer closest to the Earth's surface is the troposphere.

• There is ground-level or "bad" ozone is an air pollutant that is harmful to breathe and it

• The stratosphere or "good" ozone layer protects life on Earth from the sun's harmful ultraviolet (UV) rays.

Why should we be concerned with UV anyway…

Stratospheric ozone• is formed naturally through the interaction of solar

ultraviolet (UV) radiation with molecular oxygen (O2).

• reduces the amount of harmful UV radiation reaching the Earth's surface.

Stratosheric ozone is 6-30 miles above

ground

What does it do?• The ozone layer absorbs 97-

99% of the sun's high frequency ultraviolet light, light which is potentially damaging to life on earth.

• Every 1% decrease in the earths ozone shield is projected to increase the amount of UV light exposure to the lower atmosphere by 2%.

Tropospheric, or ground-level, ozone• forms primarily from reactions between two

major classes of air pollutants: volatile organic compounds (VOCs) and nitrogen oxides (NOx).

• more ozone forms in the summer months because of the heat and sunlight.

Tropospheric ozone is 0-7 miles above

ground

Ground Level Ozone Formation

Tropospheric ozone• May through September is known as “ozone

season;” however, ozone pollution can occur throughout the year in some southern locations.

• damages crops, trees and other vegetation. It is a main ingredient of urban smog.

Discovery…• 1913

The ozone layer is discovered by French physicists Charles Fabry and Henri Buisson. Between 1913 and 1932, they show that the total amount of ozone in a vertical column of the atmosphere can be measured and that it equals (in modern units) 300 Dobson units.

Why do we need to know about tropospheric ozone?

• Respiratory health issues, damage to crops, trees and other vegetation; and main ingredient of urban smog

"Unhealthy for Sensitive Groups"

• AQI is 101 - 150. • people with lung disease,

older adults and children are at a greater risk from exposure to ozone, whereas persons with heart and lung disease, older adults and children are at greater risk from the presence of particles in the air.

Ozone Monitoring