The Ozone Layer and Its Importance

Questions and Answers

What is smog caused by?

Ozone gas created near factories (correct)

Satellites orbiting the earth

Ozone in the stratosphere

UV radiations from young stars

What is a major health implication of high ozone concentrations?

Increased lung function

Inflammation of lung tissue and chest pain (correct)

Improved breathing outdoors

Reduced risk of respiratory diseases

Why do astronomers need satellites to study UV radiations?

To get accurate UV readings on the earth's surface

To study the ozone layer in the stratosphere

To orbit above the ozone layer (correct)

To measure the amount of oxygen in the atmosphere

Who is most affected by high concentrations of ground-level ozone?

People of all ages who exercise or work outside Signup and view all the answers

What is the purpose of the EPA Air Quality Index (AQI)?

To assess ozone levels and other environmental pollutants Signup and view all the answers

What is the location of the ozone layer that filters UV radiations?

In the stratosphere Signup and view all the answers

What do young stars emit?

UV rays Signup and view all the answers

Why is it difficult for astronomers to study UV radiations from the earth's surface?

Because of the ozone layer in the stratosphere Signup and view all the answers

What do satellites help astronomers learn about?

The creation and location of galaxies Signup and view all the answers

What is the purpose of satellites orbiting above the ozone layer?

To get accurate UV data readings in space Signup and view all the answers

Study Notes

The Ozone Layer

The ozone layer is a protective gaseous layer in the atmosphere that filters the sun's radiation, known as ultraviolet (UV) rays.
UV rays contain the sun's heat and light, and excessive exposure can be harmful to living tissue, including humans and plants.

Importance of the Ozone Layer

The ozone layer is crucial for life on Earth, as it protects against skin cancer, eye cataracts, and other health problems.
It also shields plants from excessive UV radiation, which can stunt growth or cause mortality.

Composition and Structure

The ozone layer is composed of three oxygen atoms (O-O-O).
It is found in the stratosphere, 10-30 miles from Earth's surface, and has a concentration of around 12 parts per million (ppm).
The ozone layer is measured in Dobson Units (DU), with an average global value of 300 DU.

Location and Distribution

Ozone concentration varies globally, with higher densities near the poles and lower densities near the tropics.
The Brewer-Dobson circulation transfers atmospheric ozone from the tropics to mid-to-high latitudes.

Ozone Creation and Destruction

Ozone is created through chemical reactions involving UV radiation, nitrogen, and hydrocarbons.
It can be destroyed through reactions with chemicals like CFCs, which release chlorine that reacts with ozone in the presence of UV light.

History of Ozone Research

Christian Schonbein discovered ozone in 1840 during experiments on electrical odor.
In the 1870s, W.N. Hartley proposed that ozone absorbed UV light from the sun.
In the 20th century, G.M.B. Dobson invented a spectrometer to measure atmospheric ozone, and Sherwood Rowland and Mario Molina developed the fluorocarbon-ozone theory.

Ozone Depletion

The ozone layer depletion was discovered in 1985, and it was found that CFCs were the primary cause.
The Montreal Protocol was signed in 1987 to reduce CFC production and use, and it has been successful in decreasing ozone-depleting chemicals by 95%.

Efforts to Save the Ozone Layer

The Montreal Protocol has nearly 200 signatures globally, and it is projected to return the ozone layer to pre-1980 levels by 2065.
However, some countries still use CFCs, and seasonal holes in the ozone layer are expected due to stronger spring and summer UV rays.

Is Ozone Harmful?

While ozone is necessary for life on Earth, it can be harmful to human health in high concentrations near the ground.
The EPA defines a maximum ozone concentration of 0.08 ppm for outdoor exposure, and high levels can cause respiratory problems.

Implications of Ozone for Astronomy

The ozone layer filters UV radiations, making it difficult for astronomers on Earth to get accurate UV readings.
Satellites are needed to bypass the ozone layer and get accurate UV data readings in space, which helps astronomers learn about the creation and location of galaxies.