Weather Wisdom
In this lesson, you will assess the impact of weather on the Donora disaster, investigate weather effects in general and then assess the impact of weather on the transport of pollutants.
Your Assignment – How does weather impact the transport of pollutants?
Your team is looking for answers to these specific questions…
- How did weather affect the Donora disaster?
- How does weather affect the transport of pollutants?
The Action Plan – Procedures to follow
Print a copy of the worksheet to accompany Weather Wisdom.
Step 1: Gather some basic weather information
a. Weather vs. Climate - Visit the National Center for Atmospheric Research and learn how to distinguish between weather and climate.
b. Weather data – Each of the links below will allow you to see current readings on important weather information.
Several of these factors had an affect on the Donora disaster. Interpret the maps to determine that particular weather parameter in your location right now:
c. Weather Effects – Each of the terms below represent an important weather phenomena which can favorably or adversely affect the weather in a given locale. Visit the associated site and determine how each develops:
One very important meteorological factor in the Donora Disaster was the formation of temperature inversions.
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Observe Diagram 1 taken from the 1949 Public Health Service Bulletin.
This represents the average thermal structure across the Monongahela valley on a non-smoky, calm day.
What happens to the temperature as the altitude gets higher on a normal day?
Is this what you would expect to happen? Explain why or why not.
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Compare the previous diagram with this second diagram, also taken from the 1949 Public Health Service Bulletin.
What happens to the temperature as the altitude gets higher?
How might the inverted temperature layers impact the area?
Do you think that air will be able to rise up (radiate) as under normal conditions? Explain.
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Study this final diagram from the 1949 Public Health Service Bulletin.
In this diagram, how is the air moving, radiating up? Down? Side-ways?
How might this type of air movement impact pollutants moving out of the area?
What type of conditions might help to move pollutants out of the valley?
Which direction should the wind blow to clear out the maximum amount of pollutants from the area? |
Step 2: Return to Donora
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The town of Donora on different days. Notice the dramatic difference. |
Which picture of Donora was taken on a day with normal temperature conditions?
Which picture of Donora was taken on a day when a temperature inversion was occurring?
According to Devra Davis (2002, p.9), "October 26, 1948, brought a massive, still blanket of cold air over the entire Monongahela Valley. All the gases from Donora's mills, its furnaces and stoves, were unable to rise above the hilltops and began to fill the homes and streets of the town with a blinding fog of coal, coke, and metal fumes."
Source: Davis, Devra. (2002). The Heavy Air of Donora, Pa. The Chronicle of Higher Education, 10/25/2002
Weather played a very important role in the Donora Disaster. In the Meteorological Investigation of the 1949 Public Health Bulletin report 306, W.H. Hoeker, Jr. stated that the following general factors were important:
1) Sources of pollution. A variety of pollutants were released from several smokestacks less than 1000 feet high.
Why do you think this was a problem? Recall the height of the surrounding mountains before answering the question.
2) Topography - Terrain that trapped air at a low level, e.g. the valley
3) Humidity - Enough water vapor was present so fog formed.
Think about what occurs during the condensation process. Why would the presence of water vapor compound the problem?
4) Meteorological features - An anticyclone led to high pressure and trapped the pollutants
Where did the pollutants end up going during the disaster?
5) Season - October in Donora is the time of the year when the conditions are most common to form an anticyclone, fog, and temperature inversion
Use this information to help you prepare your team report. An additional useful weather reference can be found at:
The Farmer’s Almanac
Team Report
Prepare a report for the team answering the original questions:
How did weather affect the Donora disaster?
How does weather affect the transport of pollutants?
