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.

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