What is radiation fog in California?

Radiation fog, also known as Tule fog, is a type of dense fog that forms in California's Central Valley during autumn and winter when the ground rapidly cools after sunset.

Why are people getting sick in the California fog?

The fog itself doesn't cause illness, but it can trap pollutants like car exhaust and industrial emissions near the ground, leading to respiratory irritation.

When will the fog clear from California's Central Valley?

A weather system is forecast to arrive around December 17, but it is uncertain if it will be strong enough to clear the persistent fog.

Home / Weather / California Fog Hides Pollution, Sparks Health Fears

California Fog Hides Pollution, Sparks Health Fears

17 Dec

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Summary

Dense radiation fog has lingered for weeks in California's Central Valley.
Locals report respiratory symptoms and unusual white residue on cars.
Trapped pollutants are suspected of causing health issues, not the fog itself.

California Fog Hides Pollution, Sparks Health Fears

For weeks, California's Central Valley has been covered by a thick blanket of radiation fog, coinciding with a rise in reported respiratory ailments among residents. This phenomenon, also known as Tule fog, occurs when ground temperatures plummet after sunset, creating a dense, low-lying cloud. Reports from affected areas detail symptoms such as persistent coughing, congestion, and even exacerbated skin conditions like eczema.

While the fog itself is essentially water vapor and does not cause illness, it can create dangerous conditions. Temperature inversions frequently accompany these fog events, trapping car exhaust, industrial emissions, and other airborne particles close to the ground. This accumulation of pollutants can lead to significant respiratory irritation, particularly for individuals with pre-existing lung conditions like asthma.