Some kind of atmospheric inversion, I imagine, but the color mystifies me.

This dirty air probably derives from similar sources, located in areas where there is no atmospheric inversion.

This occurs when an atmospheric inversion separates two layers with a marked difference in wind direction.

July brought the heat, atmospheric inversions that muffled the entire city like a filthy plastic garbage bag.

Early the next day, the atmospheric inversion developed, and remained stable, encapsulating the odor, until wind speed rapidly increased in late morning.

Green flashes are enhanced by atmospheric inversions which increase the density gradient in the atmosphere, and therefore increase refraction.

The temperature on the plains of the river val was extremely cold; due to atmospheric inversions, often colder tha was higher in the surrounding mountains.

At a thousand meters I found our part of Venus's semipermanent atmospheric inversion, and the turbulence dropped to where I could take off my belt and stand.

In May Franklin Heller of Stamford, Conn., who is 77 years old and asthmatic, stepped off a plane into a Milanese atmospheric inversion and doubled over.

On March 10, 2004, a biologist discovered 5 dead bison which apparently had inhaled toxic geothermal gases trapped in the Norris Geyser Basin by a seasonal atmospheric inversion.

But the first weeks of the year are always a particular trial for the chilangos, as natives of the Mexican capital are known, because of the regularity and severity of atmospheric inversions.

They warned, however, that chemicals and particles from the fires could cause considerably greater health problems this summer, when the seasonal winds die down and atmospheric inversions begin to trap pollution over populated areas.

The Los Angeles Basin and the San Fernando Valley are susceptible to atmospheric inversion, which holds in the exhausts from road vehicles, airplanes, locomotives, shipping, manufacturing, and other sources.

Trapped by the circle of mountains, set low by atmospheric inversion, it acidified the air, speeding decay of the antiquities and irritating the eyes and lungs of the city's four million inhabitants.

First, there was a low tide in the coastal marshes from roughly 4 a.m. to 6 a.m. Second, we experienced winds from the south and an atmospheric inversion, which created something like a low-lying bubble of air.

While in Fall River he published a seminal paper on atmospheric inversions (1936), which again impressed Dr Rossby, who offered Namias a graduate assistantship at MIT, beginning with the 1936 Fall term.

"The 'authorities' likely lack the capability to identify things that people think smell like an industrial chemical, which are actually gases from nearby swamps released due to peculiar sequences of weather conditions and trapped by an atmospheric inversion," one blog reader at nytimes.com/empirezone declared.

If pollen is making breathing difficult, if local atmospheric inversions are sending people indoors for hours, the traveler should think of going some place where the air is clean - Copenhagen; Caracas, Venezuela, Auckland, New Zealand, for instance, which are repeatedly rated among the cleanest cities in the study's various categories.