Haze

Haze is traditionally an atmospheric phenomenon in which dust, smoke, and other dry particulates suspended in air obscure visibility and the clarity of the sky.

In meteorological literature, the word haze is generally used to denote visibility-reducing aerosols of the wet type suspended in the atmosphere.

When weather conditions block the dispersal of smoke and other pollutants they concentrate and form a usually low-hanging shroud that impairs visibility and may become a respiratory health threat if excessively inhaled.

[3] In the United States, the Interagency Monitoring of Protected Visual Environments (IMPROVE) program was developed as a collaborative effort between the US EPA and the National Park Service in order to establish the chemical composition of haze in National Parks and establish air pollution control measures in order to restore the visibility of the air to pre-industrial levels.

The main sources of the haze are Indonesia's Sumatra Island, Indonesian areas of Borneo, and Riau, where farmers, plantation owners and miners have set hundreds of fires in the forests to clear land during dry weather.

Winds blew most of the particulates and fumes across the narrow Strait of Malacca to Malaysia, although parts of Indonesia in the path are also affected.

For these reasons, sunrise and sunset colors and possibly the sun itself appear subdued on hazy days, and stars may be obscured by haze at night.

[10] Infrared (IR) imaging may also be used to penetrate haze over long distances, with a combination of IR-pass optical filters and IR-sensitive detectors at the intended destination.