Question

If the overhead ozone concentration at a point above the Earth's surface is \(250 \mathrm{DU}\), what is the equivalent thickness in millimeters of pure ozone at \(1.0 \mathrm{~atm}\) pressure?

Short answer

2.5 mm of pure ozone at 1 atm pressure.

Step-by-step solution

Understand Dobson Units Conversion

A Dobson Unit (DU) is a unit of measurement of the amount of ozone in the Earth's atmosphere. It is defined as the thickness of the ozone layer if it were compressed to standard temperature and pressure (0°C and 1 atm). 1 DU corresponds to a 0.01 millimeter thickness of pure ozone. Thus, to find the thickness in millimeters, multiply the number of Dobson Units by 0.01.

Perform the Calculation

Given that the overhead ozone concentration is 250 DU, convert this value to millimeters using the conversion factor from Step 1. \[ \text{Thickness in mm} = 250 \text{ DU} \times 0.01 \text{ mm/DU} = 2.5 \text{ mm} \]

State the Result

After performing the calculation, the thickness of pure ozone at 1.0 atm pressure equivalent is found to be 2.5 millimeters.

Key concepts

Ozone Layer

The ozone layer is a crucial part of Earth's atmosphere that contains a high concentration of ozone (O₃) molecules. This layer is located in the stratosphere, approximately 10 to 30 kilometers above the Earth's surface. It plays a vital role in absorbing the majority of the Sun's harmful ultraviolet (UV) radiation, protecting all forms of life on our planet from potential damage.

The depletion of the ozone layer has raised concerns over increased UV exposure, which can lead to skin cancer, cataracts, and other health issues. Understanding measures like the thickness of the ozone layer allows scientists to monitor its health and implement necessary protective measures.

Atmospheric Pressure

Atmospheric pressure is the force exerted by the weight of air in the atmosphere on a surface. It is typically measured in units such as atmospheres (atm), millibars (mb), or Pascals (Pa). At sea level, the normal atmospheric pressure is about 1 atm.

The pressure decreases as we move higher in the atmosphere because there is less air above us. When discussing the thickness of the ozone measured in Dobson Units, the concept is simplified by imagining how thick the ozone layer would be if it were compressed to standard pressure of 1 atm. Understanding this helps us visualize how ozone is distributed in our atmosphere.

Ozone Measurement

Ozone measurement is conducted using various methods and technologies designed to quantify the amount of ozone in the atmosphere. One of the standard units for measuring ozone is the Dobson Unit (DU).

• Dobson Units represent the physical thickness of the ozone layer if compressed to sea level pressure and temperature.
• 1 DU is equivalent to a 0.01 millimeter thickness of pure ozone.

Instruments such as ozonesondes and satellite-based sensors provide critical data for assessing ozone levels. Regular monitoring is essential to track changes in the ozone layer's thickness and health.

Unit Conversion

Unit conversion plays a significant role in understanding and interpreting scientific measurements. In the context of atmospheric sciences, Dobson Units are a key metric.

• When given a Dobson Unit value, we can convert this to a physical thickness in millimeters by multiplying the DU value by 0.01 mm/DU.
• This conversion provides a tangible way of understanding the amount of ozone present.

For example, the original problem required converting 250 DU into the thickness of 2.5 millimeters of pure ozone under standard conditions. Such conversions are essential for comparing ozone thickness to other environmental metrics.

Environmental Science

Environmental science is an interdisciplinary field that studies human interaction with the environment, focusing on solving complex environmental problems. It combines elements of biology, chemistry, physics, and other sciences to understand ecosystems, atmospheric conditions, and biodiversity.

The study of the ozone layer and its changes is a key aspect of environmental science. Scientists use data such as ozone measurements and atmospheric pressure to assess factors contributing to ozone depletion and develop strategies for mitigation. Awareness and education about ozone are critical for informed public actions and policies.