Hazy - Air Pollution

Air Pollution

Haze often occurs when dust and smoke particles accumulate in relatively dry air. 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. Industrial pollution can result in dense haze, which is known as smog.

Since 1991, haze has been a particularly acute problem in Southeast Asia, Indonesian forest fires burnt to clear land being the reason. In response the 1997 Southeast Asian haze, the ASEAN countries agreed on a Regional Haze Action Plan (1997) and later signed the Agreement on Transboundary Haze Pollution (2002) however the pollution is still a problem today. Under the agreement the ASEAN secretariat hosts a co-ordination and support unit.

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 to pre-industrial levels. Additionally, the Clean Air Act requires that any current visibility problems be remedied, and future visibility problems be prevented, in 156 Class I Federal areas located throughout the United States. A full list of these areas is available on EPA's website.