Every year, more than 280 million visitors travel through 156 national park and wilderness areas. Unfortunately, many of these people are unable to enjoy the spectacular vistas they come to see. In many eastern parks, visibility has been reduced from 90 miles to between 15 and 25 miles because of regional haze from man-made air pollution.

Regional haze occurs when fine particles scatter in the atmosphere and absorb light, limiting the distance that people can see, and obscuring the color and clarity of their view. Unlike ground-level ozone (smog), which is primarily a summertime problem, regional haze can occur during all four seasons. It can persist over wide geographic areas and can greatly reduce visibility many times during the year.

HazeCam Photo of Boston

Real-time visibility monitoring photo of Boston as seen from the Blue Hill Observatory in Milton, courtesy of HazeCam.net. Under ideal air quality conditions, the city skyline is visible. Image is updated every 15 minutes. Visit HazeCam.net for more detailed information.

Related Health Effects

Most of the pollution that causes regional haze is not emitted directly into the air, but forms after gases emitted from pollution sources are transformed in the atmosphere into fine particles that can be transported great distances by the wind. Some of the pollutants that lead to regional haze also have been linked to serious health problems:

• Fine particles can be deposited deep into the lungs, where they can accumulate on the surface or be absorbed by underlying tissue and enter the bloodstream.
  
• People with heart or lung diseases and respiratory conditions such as coronary artery disease, congestive heart failure, asthma and chronic obstructive pulmonary disease are at increased risk of serious effects because particles can aggravate these diseases.
  
• Even healthy people may experience temporary symptoms from exposure to elevated levels of particles. Symptoms may include: eye, nose and throat irritation; coughing; phlegm; chest tightness; and shortness of breath.
  
• Children are likely to be at risk from particles for a number of reasons: their lungs are still developing; they are more physically active than many adults; and they are more likely to have asthma or acute respiratory diseases that can be aggravated by particles.

What Government is Doing

The federal Clean Air Act (CAA) authorizes the U.S. Environmental Protection Agency (EPA) to address visibility in national parks and wilderness areas. In 1999, EPA issued the Regional Haze Rule requiring states and interested tribes to address haze caused by numerous sources over large geographic areas.

The Mid-Atlantic/Northeast Visibility Union (MANE-VU) is one of five regional planning organizations established by EPA to assess the impacts of different pollution sources on visibility and facilitate the development of strategies to address regional haze.

MANE-VU represents Connecticut, Delaware, the District of Columbia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, the Penobscot tribe, Rhode Island, St. Regis Mohawk tribe and Vermont, as well as federal environment, forest, park and wildlife agencies. MANE-VU also works with Northeast States for Coordinated Air Use Management (NESCAUM) and the Mid-Atlantic Regional Air Management Association (MARAMA).