## What’s being done about haze? What can you do? Many Clean Air Act programs are already in place to reduce haze-forming pollutants over the coming decades. These include several U.S. Environmental Protection Agency (EPA) rules: the 2005 Clean Air Interstate Rule, the 1999 regulations to reduce haze and protect visibility, and the 1992 Acid Rain Rule. State and local air quality agencies are putting together plans to reduce regional haze in national parks and wilderness areas. These are the first steps in meeting the national goal of eliminating the manmade pollution that impairs visibility. U.S. EPA and the U.S. Departments of Interior and Agriculture are working with state, local and tribal authorities to promote steady improvements in visibility and provide other protections to people and their surroundings for decades to come. As the U.S. population and the number of vehicles continue to increase, we are all challenged to do our part to reduce air pollution. Conserve energy; participate in local energy conservation programs Carpool or use public transportation Keep car, boat and other engines properly tuned Minimize open burning Recycle 

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# For more information, visit

www.epa.gov/visibility The same pollution that causes

haze also poses health risks.

Office of Air Quality Planning and Standards Research Triangle Park, NC 27711

EPA-456/F-06-001, April 2006 

# EPA **United States Environmental Protection**  **Agency**

# How far can you see? Every year over 280 million people visit our nation’s treasured parks and wilderness areas. Unfortunately, many visitors aren’t able to see the spectacular vistas they expect. During much of the year, a veil of white or brown haze hangs in the air, blurring the view. Most of this haze is caused by air pollution carried by the wind, often hundreds of miles from where it originated.

Haze conditions vary across the country. Eastern U.S. areas have more haze due to higher pollutant and humidity levels. 

# What is Haze? Haze is caused when sunlight encounters tiny pollution particles in the air. Some light is absorbed by particles. More pollutants mean more absorption and scattering of light, which reduce the clarity and color of what we see. Some types of particles, such as sulfates, scatter more light, especially during humid conditions.

Typical visual range in most of the Western U.S. is 60 to 90 miles, or about one-half what it would be without haze-causing air pollution. In most of the U.S., the typical visual range is 15 to 30 miles, or about one-third of the visual range under natural conditions. 

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## Where do pollutants come from? Air pollution that causes haze comes from a variety of sources. These include power plants, factories, and cars and trucks. Natural sources can include windblown dust and soot from wildfires. Some haze-causing particles are directly emitted into the air. The vast majority are formed when gases emitted into the air react to form particles as they are carried great distances from the source of the pollution. 

## How do these pollutants affect you and your surroundings? Some of the pollutants which form haze have also been linked to serious health problems and environmental damage. Exposure to very small particles in the air has been linked to increased respiratory illness, decreased lung function and even death. Some particles contribute to acid rain formation, which can make lakes, rivers and streams unsuitable for fish. Acid rain can also damage buildings, historical monuments and the paint on cars. Pollutants that cause haze may also form ground-level ozone, another harmful pollutant. Regional haze obscures the view in our nation’s parks. Light scattered and absorbed by pollution particles makes the background appear hazy.

More Haze Less Haze = particles in sight

**Visual Range** Pollution particles in the air absorb or scatter the light so the view is not as clear or as far as it should be. u