Haze facts for kids

Harmattan Haze in Abuja.

Haze is a problem with the air quality in which smoke covers the sky, making it hard for people to breathe. Some people fall sick as well due to the polluted air.

The World Meteorological Organization manual of codes includes a classification of horizontal obscuration into categories of fog, ice fog, steam fog, mist, haze, smoke, volcanic ash, dust, sand, and snow. Sources for haze particles include farming (ploughing in dry weather), traffic, industry, and wildfires.

Seen from afar (e.g. an approaching airplane) and depending on the direction of view with respect to the Sun, haze may appear brownish or bluish, while mist tends to be bluish grey. Whereas haze often is thought of as a phenomenon of dry air, mist formation is a phenomenon of humid air. However, haze particles may act as condensation nuclei for the subsequent formation of mist droplets; such forms of haze are known as "wet haze."

In meteorological literature, the word haze is generally used to denote visibility-reducing aerosols of the wet type. Such aerosols commonly arise from complex chemical reactions that occur as sulfur dioxide gases emitted during combustion are converted into small droplets of sulfuric acid. The reactions are enhanced in the presence of sunlight, high relative humidity, and stagnant air flow. A small component of wet-haze aerosols appear to be derived from compounds released by trees, such as terpenes. For all these reasons, wet haze tends to be primarily a warm-season phenomenon. Large areas of haze covering many thousands of kilometers may be produced under favorable conditions each summer.

Images for kids

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  Haze over the Mojave Desert from a brush fire in Santa Barbara, California, seen as the Sun descends on the 2016 June solstice, allows the Sun to be photographed without a filter.

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  Bushfire haze in Sydney Australia.

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  Haze as smoke pollution over the Mojave from fires in the Inland Empire, June, 2016, demonstrates the loss of contrast to the Sun, and the landscape in general.

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  Haze causing red clouds, due to the scattering of light on smoke particles, also known as Rayleigh scattering during Mexico's forest fire season.

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  Haze in Monterrey, Mexico during grassland fires.

See also

In Spanish: Calima (meteorología) para niños