What is haze?

Haze is caused when sunlight encounters tiny particles of pollutants that are in the air. Some light is absorbed by particles. Other light is scattered away before. 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. 

Where does haze-forming pollution come from?

Air pollutants come from a variety of natural and manmade sources. Natural sources can include dust from dust storms, and soot from wildfires. Manmade sources can include motor vehicles, electric utility and industrial fuel burning, and manufacturing operations. Particulate matter pollution is the major cause of reduced visibility (haze). Find out more about particulate pollution | Fact Sheet > | En español >

What else can these pollutants do to you and the environment?

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 have been linked with increased respiratory illness, decreased lung function, and even premature death. In addition, particles such as nitrates and sulfates contribute to acid rain formation which makes lakes, rivers, and streams unsuitable for some fish, and erodes buildings, historical monuments, and paint on cars. 

Arizona and the EPA have a Regional Haze Plan in place | Learn More About the Plan >