Regional Haze

Regional Haze, a widespread blanket of haze from numerous sources, obscures views in pristine areas like national parks and wilderness areas and blurs skylines. Regional Haze often appears white but can be colored differently depending on the angle of the sun and is generally the result of fine particle pollution.

'Haze' consists of particles, smoke, dust and moisture suspended in the air that impairs visibility. 'Regional Haze' refers to haze that impairs visibility in all directions uniformly.

Regional Haze can occur at any time during the year and is often transported over long distances crossing state and national borders.

In the Eastern U.S., Regional Haze comes from fossil fuel combustion including power plants, industrial boilers, industrial processes, and transportation such as cars and trucks.

The majority of the pollution causing Regional Haze is not released directly into the atmosphere, but forms after gases released from pollution sources are transformed through chemical reactions into fine particles.

Regional planning agencies have been formed across the United States. One such agency is MANE-VU-- the Mid-Atlantic/Northeast Visibility Union. MANE-VU includes the following states: Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Maryland, Delaware and also the District of Columbia. Two Native American tribes are also part of MANE-VU: the Penobscot Indian Nation and the St. Regis Mohawk Tribe. The Federal agencies involved include EPA, the U.S. Forest Service, U.S. Fish and Wildlife Service and the National Park Service.

Currently, MANE-VU states are using EPA's guidance to calculate natural visibility conditions in the East which are estimated at over 100 miles in some locations. Under current polluted conditions, average visibility ranges from 40 to 60 miles. Under the most polluted conditions, regional haze reduces visibility to as low as just a few miles.

Maine is actively working with MANE-VU to reduce Regional Haze effects within the region as a whole and within the state. Part of this effort includes joining with EPA, other States, local environmental agencies, Tribes and Federal Land Managers to work together in reducing Regional Haze at national parks and wilderness areas in the State.

Fine particle pollution, which causes haze, affects human health and can have serious effects on animals, plants, lakes, streams, soils, and visibility in millions of acres of parkland and wilderness areas.

Unlike Regional Haze, air pollution can also appear as a localized brown cloud in wintertime. The brown appearance is caused by a higher level of nitrates from industry and transportation and usually occurs over urban areas. Brown clouds tend to occur on calm winter mornings during rush hour traffic when cold air is trapped near the ground by warmer air above due to temperature inversions. Another more localized phenomena is plume blight which occurs when pollutants are emitted into a stable atmosphere and transported in some direction with little or no vertical mixing. Plume blight appears as a narrow band or layer. Both brown cloud and plume blight can reduce visibility, however they are not widespread.

For more information on the various aspects of Regional Haze please use the links to the left. Use the links below to access more specific regional haze information.


		EPA New England
	HazeCam