National Wildlife Refuge System

Scenic Views at Salt Creek Wilderness Area Scenic Views at Salt Creek Wilderness Area Scenic Views at Salt Creek Wilderness Area Scenic Views at Salt Creek Wilderness Area

Bitter Lake National Wildlife Refuge - Salt Creek Wilderness

Air Pollution Impacts


Natural and scenic resources at the Salt Creek Wilderness Area are susceptible to the harmful effects of air pollution. Fine particles and toxic emissions, nitrogen/sulfur deposition, and formation of ozone can impact scenic resources. In addition to affecting visibility, these pollutants can potentially harm natural resources such as surface waters, fish, wildlife, and vegetation. Click on the tabs below to learn more about air pollutants and their impacts on natural and scenic resources at the Salt Creek Wilderness Area.


  • Visibility
  • Fine Particles
  • Nitrogen & Sulfur
  • Toxics & Mercury
  • Ozone



Many visitors come to wilderness areas to enjoy the spectacular vistas. Unfortunately, these vistas are often obscured by haze caused by fine particles in the air. Each major chemical component that affects haze or visibility at Salt Creek Wilderness is shown in the pie chart below. Organic compounds, soot, and dust reduce visibility as well. The pie chart below shows the average percent contribution to haze at Salt Creek Wilderness Area by each major chemical component. Sulfate causes 26% of the haze at the Salt Creek Wilderness Area. Coarse mass (dust) and fine soil contribute to 20% of the haze. Organic (OC) and elemental carbon (EC) contribute 15% to haze and sources include biomass burning, motor vehicles, and industrial sources. Rayleigh scattering is a natural optical phenomenon where light is deflected by matter. While this natural phenomenon contributes to visibility impairment, it also gives the atmosphere its blue color. The other contributors to visibility are a combination of man-made and natural elements.


Visibility effects at Salt Creek Wilderness include:

  • A reduction of the average natural visual range from about 156 miles (without the effects of pollution) to about 77 (with the effects of pollution) at the wilderness area.
  • A reduction of the average visual range to 42 miles on the most polluted days (20% highest pollution days).
  • Human produced haze frequently impairs scenic vistas at the wilderness area.
Salt Creek Visibility/Haze Contributions Graph


Visibility Data at Salt Creek Wilderness more>>

Fine particles


Public Health Concerns

Fine particles can get deep into human's lungs because of their small size and can cause serious health problems. Numerous scientific studies have linked particle pollution exposure to irritation of the airways, coughing, difficulty breathing, aggravated asthma, chronic bronchitis, heart attacks, and premature death in people with heart or lung disease.

Concentrations of fine particles in the Salt Creek Wilderness Area comply with the National Ambient Air Quality Standards set by the U.S. Environmental Protection Agency (EPA) to protect public health. Fine particles (smaller than 2.5 micrometers) originate from either direct emissions from a source (primary particle) such as construction sites, power plants and fires, or secondary particles which are created from reactions with gases and aerosols in the atmosphere emitted from sources upwind. For example, power plants, industries, and automobiles emit gases such as sulfur dioxides and nitrogen oxides, which form particles of sulfate and nitrate in the atmosphere.  


Nitrogen and Sulfur


Nitrogen and sulfur compounds deposits may cause acidification in the ecosystems at the Salt Creek Wilderness Area. Also, nitrogen deposition may cause nutrient imbalances in the ecosystem, sometimes leading to increases in weedy plant species and cause the loss of native species. Although the EPA's Acid Rain Program and other air quality management programs have significantly reduced sulfur deposition and nitrogen deposition, some areas continue to show the effects of acid deposition.


Wet deposition of nitrogen and sulfur at NADP site NM08, 1985-2010.

Wet deposition (from rain and snow) is not monitored at the Salt Creek Wilderness, but has been monitored since 1984 at the Mayhill, NM (NM08) site in the Lincoln National Forest, about 40 miles southwest of Salt Creek Wilderness. The plot below shows annual average values of nitrogen and sulfur from wet deposition at the site from the years 1985-2010. Wet deposition data for both nitrogen and sulfur at Lincoln National Forest is gathered through the National Atmospheric Deposition Program. (NADP)

Annual Wet Deposition at Mayhill, NM Graph


Nationwide Nitrogen and Sulfur Deposition

The sulfur and nitrogen deposition near the Salt Creek Wilderness Area is similar to levels at other western US sites. The total annual sulfate and nitrogen wet deposition throughout the United States for 2009 is shown below. Click on the maps to see better resolution images.

Nitrogen Deposition
Inorganic Nitrogen Wet Deposition 2009
US Map of Sulfate Ion Wet Deposition
Sulfate Ion Wet Deposition 2009


Nitrogen and Sulfur Deposition Data at Salt Creek Wilderness more>>

Toxics & Mercury (Hg)


Toxics, including heavy metals like mercury, accumulate in the tissue of organisms is known as bioaccumulation. In the environment mercury converts to methylmercury and then enters the food chain. The effects of mercury can include reduced reproductive success, impaired growth and development, and decreased survival. Human activities greatly have increased the amount of mercury in the environment through processes such as burning coal for electricity and burning waste. Deposition of mercury from the air into water bodies often starts the bioaccumulation process. An example of bioaccumulation is where plankton will take up mercury and are eaten by smaller fish, which are eaten by larger fish and then eaten by humans. This bioaccumulation affect causes potential adverse health effects in people.


Effects of mercury and airborne toxics on ecosystems at Salt Creek Wilderness include:

  • Elevated mercury, PCB’s, and DDT concentrations in some fish species have caused the New Mexico Environment Department to recommend limited consumption.


Additional Information:

Currently, there is no mercury deposition monitoring near the Salt Creek Wilderness.  The closest mercury monitoring sites are at Navajo Lake (NM98) in northwestern New Mexico and Cimarron National Grassland (KS99) in the southwestern corner of Kansas. These sites are part of the National Atmospheric Deposition Program’s Mercury deposition network (NADP). Click on the map to see a better resolution image.

U.S. Map of Mercury Deposition Network
Map of Mercury Deposition


Mercury data at Salt Creek Wilderness more>>



Public Health and Ecosystem Concerns

Naturally-occurring ozone in the upper atmosphere forms a layer that absorbs the sun’s harmful ultraviolet rays and protects all life on earth. However, in the lower atmosphere, ozone is considered an air pollutant. Ozone forms when nitrogen oxides from vehicles, power plants, and other sources combine with volatile organic compounds from gasoline, solvents, and vegetation in the presence of sunlight. In addition to inducing respiratory problems in people, elevated ozone exposures can injure plants. Ozone enters the plant leaves through pores (stomata), where it can kill plant tissues, causing visible injury like bleaching or dark stippling, or reduces the plants ability to photosynthesis, growth, and reproduction.

In humans, ozone is a respiratory irritant. Research shows that ozone can cause coughing, sinus inflammation, chest pains, scratchy throat, permanent lung damage, and reduced immune system functions. Children, the elderly, people with existing health problems, and active adults are most vulnerable to the effects of ozone.


Ground-level ozone concentrations at Salt Creek Wilderness are have recently dropped to be within the National Ambient Air Quality Standard (NAAQS) set by the U.S. Environmental Protection Agency (EPA) to protect public health. 

The current 8-hour average standard is 75 parts per billion (ppb). Compliance with the standard is based on the three-year average of the 4th highest daily value per year. EPA’s Clean Air Scientific Advisory panel has recommended a new standard to 60-70 ppb. There are no ozone monitoring sites at Salt Creek Wilderness. Ozone has been monitored at Carlsbad, New Mexico about 60 miles north of Salt Creek Wilderness.  The three year average of the yearly 4th highest 8-hour ozone concentration has ranged from 67-72 ppb for 3-year average periods between 1998-2000 and 2008-2010. These values are all less than the current NAAQS of 75 ppb.

3-year average 4th highest 8-hour average concentration Graph


Effects of ozone on vegetation at Salt Creek Wilderness

The EPA has proposed that a weighted index, called “W126” be used to evaluate potential damage to vegetation from ozone.  EPA proposed a secondary air quality standard for ozone to protect vegetation with a W126 between 7-15 ppm-hr based on a 3-year average.  The 3-year average indices at Carlsbad, NM for 3-year periods starting in 1998-2000 until 2008-2010 ranged from 8.6-15.0 ppm-hr. For all three year periods the index was between the low and high ends of the recommended range to protect vegetation from injury.

3-year average W126 index Graph


Plants that are sensitive to Ozone at Salt Creek Wilderness more>>




Last updated: November 8, 2012