You've probably had the experience. You hoof your way up to a mountain summit expecting to be rewarded by a sweeping vista, and, alas, haze reduces your view to a shadow of what it might have been.
That's bad enough for people who love the beauty of the outdoors, but the problem is even worse than it appears. The haze that you see is caused by fine particles of pollution, which scatter and absorb sunlight, obscuring the color and clarity of what you see. If you can see these pollutant particles as haze, it means that you are also breathing them in. These fine particles have been connected to increased mortality and respiratory disease in nationwide studies. In addition, when these fine pollution particles fall back to the earth they damage ecosystems much like acid rain does.
Haze caused by fine particulate matter is a serious problem throughout the Appalachian mountain range, from the Great Smoky Mountains National Park of North Carolina and Tennessee to Maine's Acadia National Park. The AMC is studying the problem in the White Mountains of New Hampshire, in cooperation with the White Mountain National Forest and others.
The Study
The AMC and its partners are gathering extensive data on haze and visibility conditions in the White Mountains, the composition of haze pollutants, and how these two factors are related. Visibility monitoring in the Great Gulf Wilderness Area was initiated in September 1985 with the installation of a visibility camera at the AMC's Camp Dodge facility. Camp Dodge looks out on the Great Gulf, which lies about one and a half miles to the west. The Great Gulf was designated as a "Class 1 airshed" in the 1977 amendments to the Clean Air Act. As such, the goal for this area is "the prevention of any future, and the remedy of any existing, impairment of visibility from manmade air pollution."
In addition, since 1988, the AMC has been monitoring the concentration and composition of fine particles in the air at Lakes of the Clouds Hut and Camp Dodge. (See a map of monitoring locations.) Researchers measure the concentration of small particles in the air using a " particle monitor" known as a Harvard Impactor (see a schematic diagram of this particle monitor and its operation). Particles are collected on a pre-weighed filter using a small air pump over a 24 hour period. The filter is then weighed and chemically analyzed to determine how much and what types of particulate matter were in the air sample.
The Findings
Using such techniques, researchers have documented that visibility in the Great Gulf Wilderness Area is impaired by haze. In the nine-year period from 1988 to 1996, the median summertime daily visibility in the Gulf was about 54 miles, compared with the natural visual range of approximately 80 to 90 miles.
Researchers have also been able to determine the composition of the fine particles causing the haze. AMC results show that fine sulfur particles are the primary cause of haze in the White Mountains. On average, 50 percent of the particles captured in the particle monitor are sulfates (primarily from coal-burning power plants), and on the haziest days, 80 percent of the particle composition is sulfate. There is a strong negative correlation between sulfates and visibility; in other words, as sulfates increase, visibility decreases.
Other secondary contributors to haze in the White Mountains are organic carbon and nitrate aerosols, which stem from automobile emissions and other combustion processes. Although there are local sources of both sulfates, nitrates, and organic carbons, much of this pollution travels on air currents from hundreds of kilometers away and therefore is termed "regional haze." Sulfates travel the furthest, which is one reason why they're the biggest offenders in the White Mountains and other rural areas.
The AMC also found evidence that the fine particulate matter in the White Mountains can reach levels harmful to human health. Over one 10-hour period in July 1995, unhealthy fine particle levels as high as 85 µg/m3 (micrograms per cubic meter of air) were recorded by the AMC, compared to the national health standard of 65 µg/m3 per 24-hour sample.
What Can You Do?
Given that much particulate matter pollution stems from human activity, there are many steps we can each take as individuals to help reduce the problem:
- Use less electricity. Electric power generation is one source of the fine particle pollutants that cause unhealthy haze.
- Use clean modes of transportation, such as bikes or low-emission vehicles; carpool and limit the amount you drive. Automobile exhaust is another source of particulate matter pollution.
- Support environmentally sound regional air-quality policy.
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- Become a member of a conservation group, such as the AMC.
- Keep up to date on pressing environmental issues and voice your opinion on proposed policy changes. You can do this by joining our free Conservation Action Network, which will send you monthly updates plus periodic emails when it's time to take action on important issues such as air quality.
You can also take steps to limit your personal exposure to unhealthy fine particulate matter. Like ozone, particulate matter in the air is often worse in the summer, but unhealthy levels can occur in winter, too, depending on local sources of pollution where you live and/or wind patterns that transport pollution particles. To find out the daily air-quality forecast near you, listen to radio reports or check the Air Quality Index on the Web. One good site to check is the Hikers for Clean Air Website, which has links to air-quality forecasts for each state along the Appalachian Trail. Limit strenuous outdoor activity on days when particulate matter is high, and be sure to reduce your exertion if you notice symptoms such as coughing, wheezing, tightness in the chest, and/or restricted breathing.
