What is haze?- Where does the haze pollution come from?
- How does haze impair visibility?
- How does haze pollution affect hiker and ecosystem health?
How does haze impair visibility?
In the Eastern U.S. over 70 percent of the reduction in visibility can be traced to fine particle sulfates. These sulfate particles are created when power plants located as far away as the Midwestern United States emit sulfur dioxide that reacts in the atmosphere and is blown into our region on prevailing winds. These pollutants, often associated with urbanized areas, are all too common in the mountains and the backcountry areas many Americans seek out for quiet recreation and to escape the dirty air in our cities and suburban areas. The problem of haze in the Northeast is exacerbated by the high humidity experienced in the summer months. During periods of high humidity, nitrate and sulfate particles can expand more than three times in size, increasing haze further and reducing visibility during times of peak recreational use of our public lands. However, humidity alone does not impair visibility.
Small airborne particles (fine particulates of less than 2.5 micron in size) block views by absorbing and reflecting light. Below see a view from Acadia National Park under different air pollution levels. You can toggle between the radio buttons to view the movie in relation to different units of visual range; miles, pollution concentrations (in micrograms per meter cubed), or deciviews (a log scale unit used by scientists to relate human perceived visual range reductions to pollution levels).
