A Thermal Inversion Example in Donora | AP Environmental Science | Khan Academy

Summary

In October 1948, the small town of Donora, Pennsylvania, was engulfed by a deadly smog known as the Donora death fog. Industrial emissions from steel plants, trapped by a temperature inversion, caused a toxic air disaster, leading to respiratory problems for half of the town's population and 20 deaths. The smog only cleared after a rainstorm and the shutdown of the mills. This tragic event highlighted the life-threatening dangers of air pollution and marked the beginning of the Clean Air Movement in the United States, ultimately pushing for widespread environmental change.

Takeaways

• 😀 The video begins by discussing the Donora, Pennsylvania air pollution disaster in October 1948.
• 😀 A thick yellowish smog enveloped the town, making it difficult to breathe and blocking out the sun.
• 😀 The smog was so dense that streetlights were needed during the daytime.
• 😀 The toxic air was caused by industrial emissions from steel plants and mills, including hydrogen fluoride and sulfur dioxide.
• 😀 Normally, these toxic gases would disperse into the atmosphere, but a temperature inversion trapped them in the town.
• 😀 The inversion caused a blanket of warm air to cover the colder air near the surface, trapping pollutants.
• 😀 The toxic air led to widespread respiratory issues for half of the town's 14,000 residents.
• 😀 Twenty people died due to the severe air pollution during the event.
• 😀 The smog was only relieved when the steel mills were shut down, and a rainstorm cleared the air.
• 😀 The Donora death fog became a turning point in U.S. history, leading to the rise of the Clean Air Movement.

Q & A

What was the Donora death fog?

The Donora death fog was a thick, yellowish smog that enveloped the small industrial town of Donora, Pennsylvania, in October 1948. It was caused by toxic emissions from local steel plants, which were trapped under a temperature inversion, leading to severe air pollution.

How did the temperature inversion contribute to the smog?

The temperature inversion created a blanket of warm air above a layer of cold air near the surface, which trapped the toxic emissions from the steel mills. Normally, these gases would disperse into the atmosphere, but the inversion prevented this, causing the pollutants to accumulate in the town.

What harmful gases were released by the steel plants in Donora?

The steel plants in Donora released toxic gases such as hydrogen fluoride and sulfur dioxide during the processing of steel and other metals.

What impact did the Donora death fog have on the local population?

The Donora death fog caused respiratory problems for half of the 14,000 people living in the town, and it led to the deaths of 20 individuals. The smog made it difficult to breathe and stung people's eyes.

When did the Donora death fog occur?

The Donora death fog occurred from October 26th to October 31st, 1948.

How was the smog alleviated in Donora?

The smog was alleviated when the steel mills were shut down, and a rainstorm helped clear the air by reducing the concentration of pollutants.

Why was Donora significant in the history of air pollution in the U.S.?

The Donora death fog marked a turning point in the U.S. history of air pollution. It was one of the worst air pollution disasters in the country, and it sparked public awareness of the dangers of air pollution, leading to the Clean Air Movement.

What was the Clean Air Movement?

The Clean Air Movement was a public campaign that emerged after the Donora smog disaster, advocating for stronger regulations and actions to combat air pollution and protect public health.

What role did the steel mills play in the Donora death fog?

The steel mills in Donora played a central role in the death fog by emitting toxic pollutants like hydrogen fluoride and sulfur dioxide. These emissions contributed to the smog when they were trapped by the temperature inversion.

What was the public response to the Donora smog disaster?

The public response to the Donora smog disaster was one of shock and concern. Citizens began to recognize the serious health risks posed by air pollution, and they demanded change to prevent such disasters from happening again.