Location of Aquatic Ecosystems

Affected by or Sensitive to Air

Pollutants

Because of differences in bedrock geology, soil

development, and hydrology, those Rocky Mountain lakes having the smallest acid neutralizing

capacity are clustered in specific mountain

ranges, such as the Bitterroot Range (Montana)

and the Wind River Range (Wyoming). Lakes in

the Cascade Range and the Sierra Nevada with

small acid neutralizing capacity tend to be more

evenly distributed. Many of these clusters of lakes

with low acid neutralizing capacity occur within

class I areas (fig. 18). The greatest risk of damage

from atmospheric deposition is likely in these

clusters of lakes with very low acid neutralizing

capacity and nearby, but unsampled, lakes,

streams, and ephemeral pools.

Routine chemical analyses of the snowpack and

wetfall as well as of the lakes, streams, ponds,

and ephemeral pools would be most effective in

protecting critical aquatic ecosystems if focused

on systems having low acid neutralizing capacity.

Information Needed for Assessing

Future Risks to Aquatic Ecosystems

Lakes and streams in the interior Columbia River

basin showed little evidence of acidification;

however, many are likely to respond rapidly to

changes in atmospheric deposition. Given the

number of lakes and streams in the region, and the

number of important watershed characteristics

that may affect watershed response to acidity, few

index systems are monitored routinely. Thus,

preparation of any watershed model appropriate

for the evaluation of regional acidification is hampered. Such models need to be calibrated to include the variability of geology, soil, vegetation,

climate, atmospheric deposition, and hydrologic

characteristics common to the region. Presently

(1995), data do not exist to calibrate and verify

such models, except for a few individual

watersheds.

At present, monitoring networks have few sites at

appropriate elevations to determine adequately

whether watersheds are adversely affected by

atmospheric deposition. Instruments that work at

high elevations are difficult to use or are unreliable: thus, data on the quantity and quality of wetfall at high elevations generally are unavailable.

Direct measurements of dry deposition, fog, and

rime ice are needed at high elevations.

Because of access problems at high elevations,

measurements of aquatic chemistry during periods of snowmelt or intense rainfall are hindered.

Most data collections of lake and stream chemistry are restricted to sampling during midsummer

through early fall. This period is not as likely to

indicate early stages of acidification as is the period of snowmelt.

Only a few watersheds in the Rocky Mountain region have been studied with respect to watershed

processes important to acidification. Regional

data about soil-exchange chemistry, weathering

reactions, ground water chemistry, in-lake processes, and hydrologic flow paths are almost nonexistent. These same data are even less common

in watersheds typical of those sensitive to acidification. No catchment-size areas exist in sensitive watersheds in which experimental manipulation has been done.

To evaluate or predict acidification of sensitive

watersheds, it will be necessary to determine how

much effect a given change in emissions from a

particular source (or sources) will have on atmospheric deposition. The comparative effects of

local, regional, or extraregional human or natural

sources in controlling the chemistry of atmospheric deposition need to be determined.

In summary, watershed studies need to represent

the variety of geographic and geologic conditions

and the full seasonal range of hydrologic conditions common to watersheds sensitive to acidification. Information is needed on the effects of

changes in emissions to atmospheric deposition

and how those changes affect watersheds. Watershed and in-lake processes need to be incorporated into realistic models to simulate existing

conditions and responses to pollution sources, to

predict effects from potential sources, and to

guide data collection and monitoring.

Terrestrial Ecosystems

To assess present impacts of air pollutants on vegetation in the interior Columbia River basin, we

chose to concentrate on four major air pollutants:

sulfur dioxide (SO2), nitrogen oxides (NOx),

ozone (O3), and fluoride (F) (table 1). Less

32
emphasis is placed on F because it is now important only locally. Ozone will increase with increases in NOx emissions; thus, its potential

effects on vegetation in the basin are emphasized.

Sulfur Dioxide Effects on

Terrestrial Ecosystems

Vascular plant and cryptogam sensitivity to

sulfur dioxide—Sulfur dioxide enters the leaves

through open stomata where it is oxidized to

highly toxic sulfite (SO3) and then to less toxic

sulfate (SO4). Prolonged exposure to SO2 can

result in the accumulation of high levels of sulfate in the leaf tissue which causes chronic sulfate

toxicity. In conifers, this causes a yellow-green to

red-brown coloration of the needle; in broadleaved plants this can be a general chlorosis of the

leaf. Because SO2 is assimilated through the

stomata, sensitivity of well-watered plants would

be expected to be greater than water-stressed

plants. Damage therefore may be more likely

during wet years or in wet-moist habitats (riparian

areas).

Of all vascular plant species tested, alfalfa is the

most sensitive species (Davis and Wilhour 1976).

From limited data on tree seedlings, Hogsett and

others (1989) found that SO2 concentrations below 20 ppb (24-hour mean) do not produce visible

symptoms, yet slight injury is found in ponderosa

pine and lodgepole pine above 40 ppb and moderate injury can be expected above 65 ppb.4 Slight

injury also was observed for Douglas-fir exposed

to above 65 ppb SO2. To protect all vascular plant

species, maximum SO2 concentrations should not

exceed 40 to 50 ppb (24-hour mean), and annual

average SO2 should not exceed 8 to 12 ppb

(Peterson and others 1992a, 1992b).

Generally, lichens and mosses are more sensitive

to SO2 than are vascular species (Peterson and

others 1992b) and may be the most important species to investigate for SO2 impacts. To protect

lichens from impact, the concentration of SO2 for

prolonged periods should not exceed 3 to 5 ppb.

Sensitive species are likely to be impacted if concentrations are between 5 to 15 ppb; species with

intermediate levels of sensitivity may be impacted

when exposed to 10 to 35 ppb SO2; tolerant species may not show symptoms until they experience prolonged exposure to concentrations

greater than 30 ppb (Peterson and others 1992a,

1992b).

Sulfur within the basin—Damage to vegetation

from SO2 emitted during late 1920s to mid 1930s

smelting operations in Stevens County, WA,

and in Montana was observed by Sheffer and

Hedgecock 1955. The sensitivity listings from

these field observations and some field fumigations are as follows, listed in descending order of

sensitivity:

Conifers Broadleaf trees Forest shrubs

Grand fir Thinleaf alder Pacific ninebark

Subalpine Western paper Western

fir birch poisonivy

Western Sitka Lewis

redcedar mountain-ash mockorange

Western Water birch Wild rose

hemlock

Douglas-fir Douglas maple Saskatoon

serviceberry

Western Bitter California

white pine cherry hazel

Ponderosa Common Shinyleaf spirea

pine chokecherry

Lodgepole Elderberry Sticky currant

pine

Western Willow Columbia

larch snowberry

Engelmann Columbia Redstem

spruce hawthorn ceanothus

Western Black Snowbrush

juniper cottonwood ceanothus

Pacific Black Redosier

yew hawthorn dogwood

Quaking aspen Smooth sumac

The approximate order of SO2 sensitivity, as

determined from field observations, of trees

growing near a smelter in Montana is given in

descending order of sensitivity (adapted from

Sheffer and Hedgcock 1955): subalpine fir,

Douglas-fir, lodgepole pine, Engelman spruce,

ponderosa pine, limber pine, Rocky mountain

4 juniper, common juniper. Scientific names for all plant species are given in

appendix 3.

33
Rankings determined from field observations and

exposures for other western conifers are presented

below (Davis and Wilhour 1976). No air chemistry measurements accompanied these field data,

so they cannot be used to establish specific exposure thresholds. Species are given in descending order of sensitivity to SO2: western larch,

Douglas-fir, Engelman spruce, western white

pine, western hemlock, lodgepole pine, Pacific

silver fir, white fir, western redcedar.

Rankings determined from field observations and

exposures for other western broad leafed trees and

western woody shrubs are presented below (Davis

and Wilhour 1976). No air chemistry measurements accompanied these field data, so they cannot be used to establish specific exposure thresholds. Species are listed in descending order of

sensitivity to SO2:

Broadleaf trees Woody shrubs

Very sensitive

Bitter cherry Ninebark

Quaking aspen Ocean spray

Western paper birch Serviceberry

Sensitive to intermediate

Apple (cultivated) Current

Black cottonwood Gooseberry

Locust Grape

Mountain alder Hazel

Red hawthorn Mountain laurel

Rocky mountain maple

Sitka mountain ash

Willow

Intermediate

Apricot (cultivated) Elderberry

Cherry (cultivated) Mock orange

Common chokecherry Snowberry

Elderberry Thimbleberry

Peach (cultivated)

Pear (cultivated)

Plum (cultivated)

Tolerant

Elm Buck brush

Horse chestnut Buffalo berry

Dogwood

Kinnikinnick

Oregongrape

Spiraea

Sumac

In the past several decades, stack heights have increased considerably, thus diluting the emissions

before the SO2 contacts the vegetation. The increase in stack height has reduced vegetation

damage near the source yet has caused the emissions to be deposited over a greater area downwind or to be transformed to sulfates and then

deposited.

Currently, there are sulfur dioxide monitoring

sites to the west and east of the assessment area

(table 2), yet only three within the assessment

area. These are National Dry Deposition Network

sites. The annual average SO2 concentration at

sites in Port Angeles, Seattle, Tacoma, and

Clallum County, WA; and East Helena, MT, are

within or exceed the suggested maximum concentration (8 to 12 ppb) for the protection of vascular

vegetation. In addition to the sites listed above,

the annual average SO2 concentration at sites in

Cosmopolis, Hoquiam, March Point, Bellingham,

Everett, Calas, and Clallum County, WA;

Portland, OR; and Jefferson County, MT, are

within or exceed the suggested maximum (3 to 5

ppb) for the protection of lichens. These high

values include all monitoring sites in the area except Broadwater County, MT (Continental Lime;

1 ppb annual average), Lewis County, WA

(Mount Rainier National Park; <1 ppb annual

average), and the three National Dry Deposition

Network sites within the basin.

The three National Dry Deposition Network sites

within the assessment area are in Nevada, Idaho,

and Glacier National Park, MT (fig. 15). All three

stations report very low annual mean concentrations. The highest concentrations were at Glacier

National Park with an annual mean of only 0.25

ppb SO2, well below the threshold for damage for

vascular plants and lichens. This location also had

a greater proximity to emissions of sulfur from

point sources than any other class I area within

the basin (table 1). Figure 22, displays the proximity of class I areas to SOx point sources overlaid with 30-year mean surface winds for January

and July. Without more monitoring data, it is not

possible to assess the current condition of vegetation or cryptogams for SO2 within the assessment

Text continues on page 38

34
Table 2—Summary of Federal, state, and local ambient SO2 monitoring data for the interior Columbia River basin assessment area

Station location Year of SO2

State City Station name Typea W. longitude N. latitude data 3-hour 24-hour Annual

− − − Parts per million − − −

OR Portland Standard Oil SLAMS 122.7416 45.5623 1992 0.048 0.03 0.007WA Port Angeles 1st & Chamber SLAMS 123.4144 48.1114 1991 0.117 0.035 0.008WA Port Angeles Roosevelt SPMS 123.3887 48.1027 1991 0.129 0.03 0.004WA Port Angeles 3d & Chestnut SLAMS 123.3991 48.1134 1991 0.183 0.055 0.011WA Cosmopolis School Bus Garage SLAMS 122.457 46.9304 1991 0.128 0.059 0.005WA Hoquiam Poseys SLAMS 123.8654 46.9716 1991 0.36 0.055 0.006WA Anacortes Texaco South SLAMS 122.5585 48.4667 1991 0.191 0.041 0.004WA March Point Kiesser SLAMS 122.5494 48.486 1991 0.14 0.043 0.006WA Bellingham Chestnut Street SLAMS 122.4828 48.7502 1992 0.073 0.023 0.007WA Seattle Duwamish NAMS 122.337 47.5585 1992 0.069 0.027 0.01WA Tacoma Lyle SLAMS 122.4074 47.2667 1991 0.08 0.075 0.004WA Tacoma 54th Avenue NE NAMS 122.3742 47.2808 1992 0.083 0.042 0.01WA Tacoma Alexander Avenue SLAMS 122.3832 47.2658 1992 0.074 0.026 0.009WA Everett Hoyt Avenue SLAMS 122.2227 47.9408 1992 0.041 0.017 0.006WA Camas Armory Building SPMS 122.4295 45.5873 1991 0.08 0.031 0.007WA Clallum Co. Olympic NP NPS 123.4256 48.0975 1993 0.015 0.048 0.065WA Lewis Co. Mount Rainier NP IMPROVE 122.1217 46.7614 1993 0.001MT Broadwater Co. Continental Lime SLAMS 111.6092 46.3314 1993 0.001 0.001MT Jefferson Co. Microwave Site SLAMS 111.9172 46.5578 1993 0.96 0.39 0.007MT Jefferson Co. Asarco-Ash Grove SLAMS 111.9325 46.5389 1993 0.086 0.025 0.006MT E. Helena Asarco-Kleffner SLAMS 111.9103 46.5731 1993 0.097 0.041 0.007MT E. Helena Asarco-Water Tank SLAMS 111.9344 46.5833 1993 0.14 0.042 0.012MT E. Helena Asarco-Kennedy SLAMS 111.92 46.5939 1993 0.09 0.049 0.012

a SLAMS= state and local air monitoring site; SPMS= special purpose monitoring site; NAMS= National air monitoring site; NPS= national Park Service operated monitoring

site; IMPROVE= interagency monitoring of protected visual environments monitoring site.

35
A LEGEND

Class I areasLandscapecharacterizationboundaryState boundaryCounty boundary

Tons per year

< 500500 to 9991,000 to 4,9995,000 to 19,99920,000 +

30−year averageof January surfacewinds (1960−1989)Note: Windspeedis determined byarc length

36
B LEGEND

Class I areasLandscapecharacterizationboundaryState boundaryCounty boundary

Tons per year

< 500500 to 9991,000 to 4,9995,000 to 19,99920,000 +

30−year averageof July surfacewinds (1960−1989)Note: Windspeed isdetermined by arclength

Figure 22—Proximity of class I areas to sulfur oxide (SOx) point source emissions within or around the interior Columbia River basin

and 30-year mean surface winds for (A) January and (B) July.

37
area. The chemical analyses of lichen tissues can

provide a surrogate monitor of SO2 exposure, because lichens bioaccumulate S and heavy metals,

yet the exposure dynamics cannot be known without direct continuous monitoring (Stolte and

others 1993).

No current vascular plant surveys that looked

for SO2 injury within the assessment area were

found. Gates of the Mountain Wilderness and

Glacier National Park in Montana have the closest

proximity to SO2 point source emissions; Gates

of the Mountain is also near an SO2 nonattainment area (fig. 1).

The ecosystems within the interior Columbia

River basin assessment area may be becoming

more sensitive to SO2 exposure as a result of forest management practices. The exclusion of fire

is increasing the land area supporting grand fir

(Filip 1994), the most air-pollution-sensitive conifer species in the area. Alder also is sensitive to

SO2. The expansion of coverage by this species

within the basin is making the landscape

increasingly susceptible to impact by ambient

SO2 pollution.

Summary of SO2 information—For SO2 and

the condition of terrestrial resources in the basin:

1. Ambient SO2 within the basin is contributed

by sources within the area and is transported to

the basin from sources outside of the area.

2. To protect vascular plants and lichens from

direct damage caused by sulfur dioxide, annual

mean SO2 should not exceed 8 to 12 ppb for

vascular plants and 3 to 5 ppb for lichens.

3. There are only three SO2 monitoring stations

within the basin (fig. 15). They report mean

annual concentrations of SO2 below the thresholds suggested to protect vegetation.

4. It is not possible to say conclusively that SO2

is not a threat to vegetation within the assessment

area without additional ambient air monitoring

and field surveys of vegetation and lichens.

Nitrogen Oxide Effects on

Terrestrial Ecosystems

The EPA (1993) provides the most recent and

thorough review of the effects of oxides of nitrogen on plant biochemistry, growth, and yield. The

impacts of NOx on plant growth and metabolism

are not addressed here. Instead, areas of research

that address potential effects of NOx on plant

communities and ecosystems within the interior

Columbia River basin are emphasized.

Point source estimates of NOx by EPA are relatively accurate because they are calculated from

fossil fuel consumption and can be monitored

(fig. 23). Area sources, such as emissions from

biological activity, are not currently used in the

emission estimates (fig. 5) because they are much

more difficult to estimate owing to temporal and

spatial variability in rates. Chameides and others

(1994) suggest that biogenic emissions of NOx

significantly contribute to elevated ozone concentrations in the three largest agricultural production areas of the world, and that ozone concentrations in these areas may severely impact crop

productivity in the future. Because few monitoring data for ambient levels of NOx or ozone are

available for large regions within the interior

Columbia River basin, possible sources of nitrogen oxides that were not used when estimating

area emissions (EPA 1994b) and have potential

to significantly impact vegetation either directly

or indirectly will be discussed.

Emissions of NOx unaccounted for in the

basin—The emissions data used for this assessment did not include emissions of nitrogen oxides

derived from soil microbial activity because of

large uncertainties in their estimation (Davidson

1991). Nitrous oxide emissions of biogenic origin

are of interest because they act as precursors to

ozone and could potentially account for a significant amount of NO emissions in the basin. The

global budget of NO emissions by source was

estimated by Logan (1982) as follows: fossil fuel

combustion (21 teragrams NO-N per year); biomass burning (12 teragrams NO-N per year);

lightning (8 teragrams NO-N per year); and

microbial activity in soils (8 teragrams NO-N per

year). Globally, microbial activity is estimated to

provide about 16 percent of the NO emitted to the

atmosphere (Logan 1982)

38
LEGEND

Class I areasLandscapecharacterizationboundaryState boundaryCounty boundary

Tons per year

< 500

 500 to 999

 1,000 to 4,999 5,000 to 19,999

20,000 +

Figure 23—Proximity of class I areas to nitrogen oxide (NOx) point source emissions within or around the interior Columbia River basin.

39
Anderson and Poth (1989) report that the major

source of biologically derived NO is from fertilized agricultural land. Because of the large

amounts of N-fertilizer used in the basin (Oregon

Department of Agriculture 1994, Washington Department of Agriculture 1994), microbial activity

may be a substantial but unaccounted for source

of NOx in the basin. In addition, shrub-steppe

and forested ecosystems also could be seasonal

sources of NOx emissions.

Potential for biologically derived NOx from

agriculture—Hundreds of thousands of tons of

N-fertilizer are applied to agricultural ecosystems

in the basin annually (Oregon Department of Agriculture 1994, Washington Department of Agriculture 1994). In a long-term study of N-fertility

in an agricultural ecosystem near Pendleton, OR,

Rasmussen (1991) estimated that about 15 percent

of N added as fertilizer cannot be accounted for

in crops, soils, or ground water. This suggests that

N has been lost to the atmosphere. Excess N in

soil can be released through the process of denitrification as gaseous ammonia, inert N2, NO

(precursor of ozone), or N2O (Davidson 1991),

which contributes to global warming. Gaseous

N2 is normally released under anaerobic conditions that occur in water-saturated soils, an unlikely situation in dryland or irrigated agricultural

systems of the basin.

Release of N-gases from agricultural lands has the

potential to provide a substantial percentage of

NOx emissions within the basin, which may subsequently impact N-limited ecosystems. Eilers

and others (1994) suggest that the high concentrations of both nitrate and ammonium in precipitation at Craters of the Moon National Monument

in Idaho are derived regionally from fertilized

fields or feedlots. For these reasons, additional

studies on N-emissions from agricultural activities and their impact to downwind ecosystems are

warranted.

Potential for biologically derived NOx from

shrub-steppe ecosystems—No measurements of

oxides of nitrogen emissions from shrub-steppe or

juniper ecosystems of the basin were found. Both

of these seasonably dry ecosystems may function

similarly to the seasonably dry chaparral ecosystems in California, which have been measured

for NOx emissions (Anderson and Poth 1989).

Anderson and Poth (1989) state that any ecosystem accumulating a soil N-source, either ammonium (NH4

+

) or nitrate (NO3

-

), due to burning

or to slowly alternating wet-dry or freeze-thaw

cycles, may be an important source of nitrogen

oxides entering the atmosphere.

Potential for biologically derived NOx from

forest ecosystems—Any activity, such as clearcutting, fire, or other forest disturbances, that results in mobilization of N (Bowden and Bormann

1986, Klopateck 1987, Matson and others 1987)

will result in losses of both NO and N2O. The

largest potential source of nitrogen oxide losses

from forested ecosystems is from fire.

Disturbances that reduce site growth potential and

increase decay of organic matter and subsequent

release of ammonia or nitrate to soil can result in

increases in NOx emissions (Davidson 1991).

Rapid, high mortality of forest trees due to fire,

clearcutting, pests and pathogens, or catastrophic

wind results in high gaseous losses of N because

there is relatively little vegetation to take up the

excess N released to the soil after the disturbance.

Forested ecosystems of the interior Columbia

River basin are most likely net sinks for NOx

because they are normally N-limited (Aber and

others 1989), have high surface areas to intercept

and take up gaseous N as wet or dry deposition,

and except for periods of disturbance, effectively

recycle N (Bormann and others 1977).

Direct effects of NOx on vegetation—The lowest

concentrations of NO and NO2 are normally

found in nonurban, maritime regions and highest

concentrations are associated with urban areas

(EPA 1993, 1994b; Chameides and others 1994).

We are not aware of monitoring data for oxides

of nitrogen within the basin other than for urban

areas, but given the relatively low estimated emissions of NOx in the region, it is doubtful that NOx

concentrations are ever high enough to produce

visible injury to vegetation (EPA 1993, Heck and

Tingey 1979). Concentrations above 0.1 ppm for

over 100 days of exposure are needed to reduce

metabolism and growth (EPA 1993).

The time-concentration exposure relation for NO2

also suggests that visible injury would occur only

at concentrations above 2 to 3 ppm for a 1-hour

exposure period or above 1 ppm for an exposure

period of 10 hours. Because these concentrations

and exposure intervals are at least an order of

magnitude higher than what would be reasonable

40
for urban areas within the basin (EPA 1994b), it

can be assumed that ambient concentrations of

NOx do not produce visible injury to vegetation

within the basin. Concentrations of NOx causing

negative effects on photosynthesis are at least an

order of magnitude higher than those found in the

basin, thus the probability of direct negative

effects of NOx on photosynthesis and growth of

individual species within the basin is extremely

low.

Indirect effects of NOx on vegetation—The

highest potential for effects of NOx on vegetation

in the basin seems to be indirect effects of (1)

N-deposition on species composition within unmanaged, N-limited ecosystems (Ellenberg 1988,

EPA 1993); and (2) the contribution of elevated

NOx concentrations to ozone formation, which is

toxic to vegetation (see following section).

An initial step in determining whether

N-deposition is influencing plant community

composition within the basin is to determine the

levels of N-deposition currently occurring on soils

having the lowest cation exchange capacities. The

limited data on N-deposition within the basin

(Eilers and others 1994) indicate it is occurring at

low rates. Even though measured N-deposition is

low, Eilers and others (1994) suggest the

N-deposition is from human activities and thus

outside the normal range for that system. Therefore, in seasonally dry, slow-growing, N-limited

systems, enhanced N-deposition may influence

species composition (Ellenberg 1988) and may

threaten several class I areas within the basin

(table 1).

Summary of NOx effects—For NOx and the

condition of terrestrial resources in the basin:

1. Vegetation can be impacted directly by increased inputs of N via wet or dry deposition or

indirectly through fertilization effects and NOxmediated increases in ozone.

2. Area source estimates are inaccurate. NOx

emissions from fertilized agricultural land may

be substantial in the interior Columbia River

basin yet are not accounted for in the NOx

inventory.

3. For direct impacts to occur, a concentration of

0.1 ppm NOx for over 100 days of exposure is

likely to be needed to affect plant metabolism and

growth. It is unlikely that this level of sustained

exposure is occurring within the basin.

4. There is potential for vegetation to be affected

by NOx in the basin via indirect effects of

N-deposition on species composition within

unmanaged, N-limited ecosystems.

5. NOx emissions will have a significant affect on

O3 formation within the basin that may affect

plant growth (see following section).

Ozone Effects on Terrestrial

Ecosystems

In general, plant response to ozone is negatively

related to the increasing dosage to which the plant

is exposed (Reich 1987). At equal exposure dosages, exposures with higher concentrations and

shorter durations may be more damaging than

exposures with lower concentrations and longer

durations (Hogsett and others 1988). The diversity

of responses to ozone exposure within and between species, as well as interactions with other

stresses, complicate development of highly reliable dose-response functions. The EPA currently

is attempting to establish a secondary ozone

standard to protect vegetation from ozone impacts; the process was not complete at the time of

this writing.

Little ozone monitoring has been done in remote

wildernesses and parks because of logistical difficulties and cost. There are only two nonurban

monitoring sites currently operating within the

interior Columbia River basin: Yellowstone National Park, WY, and Lassen Volcanic National

Park, CA (Joseph and Flores 1993). The highest

daily maximum concentrations recorded from

1988 to 1991 ranged from 80 to 98 ppb in Lassen

and from 61 to 98 ppb in Yellowstone.

Species most at risk from ozone exposure—

Eilers and others (1994) compiled lists of species

found in the national parks and monuments of the

Pacific Northwest that have potential for sensitivity to ozone. The tree species found highly sensitive to ozone exposure are balsam poplar, quaking aspen, and ponderosa pine. Eilers and others

(1994) also indicated that trees ranked as “sensitive” would be negatively impacted by a 7-hour

41
growing-season mean of 60 to 90 ppb for conifers

and 70 to 120 ppb for hardwoods. It is reasonable

to assume that current mean seasonal ozone concentrations in the basin are significantly below

these levels (Böhm and others 1995).

Only one tree species, quaking aspen, was reported by Treshow and Stewart (1973) as sensitive to ozone out of 15 tree and shrub species

tested. Five forbs were injured by one 2-hour exposure to 150 ppb ozone. Harward and Treshow

(1975) studied 15 understory species from the

aspen zone of the Western United States to determine the long-term effects of ozone exposures.

Foliar injury was found in all 15 species tested

after exposure for 1 to 5 weeks to 150 ppb ozone.

Eleven species had visible ozone injury at

ambient ozone concentrations.

Hogsett and others (1989) exposed ponderosa

pine, western hemlock, western redcedar,

Douglas-fir, and lodgepole pine to ozone and

acid fog for one growing season and assessed

effects on growth in the second season. First-year

results suggested that ponderosa pine was the

most sensitive tree species to ozone, whereas

western hemlock and Douglas-fir were intermediate. Western redcedar and lodgepole pine were

the least susceptible to ozone. These rankings are

consistent with field studies showing that ponderosa pine is sensitive to elevated ambient ozone

concentrations in California (Miller and others

1989). Studies by Hogsett and others (1989) also

indicate that no economically important tree species in the Northwestern United States is more

sensitive to ozone than ponderosa pine.

Other than the species listed above, there is little

information on the sensitivity of natural highelevation plant species to ozone. Seven native

western herbaceous and shrub plant species were

tested for their sensitivity to ozone fumigation in

a study by Mavity and others.5 Several of these

species developed visible leaf injury after short

exposures to the low ozone concentrations typical

of Yellowstone National Park. Further research is

needed to refine the use of these species as

bioindicator species for field monitoring for

ozone impacts. Ozone concentrations and exposures tend to increase with increasing elevation

(Lefohn 1992), putting high-elevation ecosystems

at risk. Most of the class I areas also contain highelevation ecosystems and may be at risk (table 1).

Because of the lack of air-quality monitoring in

these systems, we were unable to assess whether

impacts are likely to be occurring.

Winter wheat and potatoes are two economically

important crops in the interior Columbia River

basin that are sensitive to ozone (Heck and others

1983, Kohut and others 1987, Kress and others

1987, Pell and others 1988). Ambient ozone concentrations (7-hour seasonal mean of 44 ppb) reduced the yield of winter wheat in Ithaca, NY,

compared to yields from charcoal-filtered controls

(seasonal mean 7-hour = 22 ppb) (Kohut and

others 1987). Ozone concentrations higher than

ambient were needed to reduce yields in potatos

grown in State College, PA (Pell and others

1988).

Physiological sensitivity and variation in

response—Ozone effects on vegetation have

been studied extensively. Recent reviews provide

the latest hypotheses on plant responses to ozone

(tree response, Reich 1987; allocation, Laurence

and others 1994; compensation, Pell and others

1994; forest ecosystems, Taylor and others 1994).

The most common and apparent response of ponderosa pine to chronic ozone exposure is accelerated senescence of foliage. Surveys of foliar

injury and needle retention in ponderosa pine

should be useful in identifying whether ozone is a

problem within the basin. Ozone-induced stress

also can have secondary effects beyond reduced

growth and vigor of trees, as was shown for pine

in the Los Angeles area in the 1950s (Miller

1973). Ponderosa pines weakened by air pollution also are more susceptible to root rot (Fomes

annosus) and pine beetles (Dendroctonus

brevicomis) (Cobb and Stark 1970), and these

additional stresses greatly increased mortality.

Variation in susceptibility to ozone within populations and its implications to plant communities

and ecosystems is comprehensively presented by

Taylor and others (1991). Although changes in

the genetics of annual populations have been documented near point sources of pollution (Taylor

5 Mavity, E.; Stratton, D.; Berrang, P. 1995. Effects of ozone

on several species of plants which are native to the Western

United States. Internal report. [Place of preparation

unknown]: [preparer unknown]. 61 p. On file with: U.S.

Department of Agriculture, Forest Service, Center for Forest

Environmental Studies, Dry Branch, GA.

42
1978), pollution-induced changes to tree populations are not likely at this time (Taylor and others

1994) because of the short period of stress

(ozone) relative to the length of the life cycle

for trees. Genetic selection has not had the opportunity to be manifested within native populations.

It is possible, however, that tree plantations in

some areas have been inadvertently selected for

increased tolerance to ozone through collection

of seeds from asymptomatic individuals.

Dose-response functions over a range of tree

ages and sizes—Stolte and others (1992) attempted to quantify a relation among foliar retention, chlorotic mottle of foliage, and ambient

ozone concentrations in a study of ponderosa

pine in California. They found that a sum066

ranging from 112 to 164 ppm-hours annually

caused moderate injury to ponderosa pine examined in 1986. Andersen and others (1991)

found that coarse and fine root carbohydrates

are significantly reduced by exposure to elevated

ozone. New root growth just before budbreak

also is significantly reduced in ozone exposed

seedlings. Furthermore, reductions in ozoneinduced root growth potential may be related to

the increased incidence of root rot in ozonestressed ponderosa pine in California (Cobb and

Stark 1970).

The National Crop Loss Assessment Network developed a series of dose-response functions for

the major economic crops in the United States

(Heck and others 1983). All models indicated

slight to significant reductions in yield under

ambient ozone concentrations near Ithaca, NY,

and Chicago. Pell and others (1988) present a

linear model for effects of ozone on potato, but

they found significant reductions in yield only at

ozone concentrations above ambient. It is doubtful that present ozone concentrations in the basin

affect potato yields; however, it is possible that

sensitive winter wheat cultivars such as Vona

(Kohut and others 1987) may have reduced yields

due to ambient ozone concentrations in the basin.

Analyses of ambient ozone data for the Western

United States (Böhm and others 1995) indicate

that concentrations are substantially lower regionwide in the basin than in California and the Eastern United States. It is possible that downwind of

urban and industrial areas in or outside the basin,

ozone concentrations may increase sufficiently to

negatively affect sensitive native and agricultural

species. Increased monitoring, in conjunction with

better pollution modeling capacities, is needed to

accurately predict ambient ozone concentrations

in the basin.

Summary of O3 effects—For O3 and the condition of terrestrial resources in the interior

Columbia River basin:

1. Ozone has the greatest potential of any air pollutant to directly reduce growth and vigor of vegetation in the basin because it is highly phytotoxic

and is found globally in elevated concentrations.

In addition, the levels of its precursors (NOx and

hydrocarbons) is increasing within and upwind of

the basin.

2. Ozone and its precursors can be transported

hundreds of miles and therefore can threaten resources in remote areas.

3. Ambient air quality data for ozone in the basin

is less well characterized than for the rest of the

United States.

4. The most sensitive tested species within the

basin may be impacted by a 7-hour growingseason mean of 60 to 90 ppb of ozone for conifers

and 70 to 120 ppb for hardwoods.

5. Recent analyses of ozone monitoring data in the

Western United States suggest that the seasonal

mean ozone concentrations are significantly below the suggested threshold levels. These levels

may be exceeded however, near urban areas or

downwind from sources of ozone precursors.

6. Ozone-induced stress may have secondary

effects beyond reduced growth, such as increased

susceptibility to root rot and insect infestation.

Fluoride

Injury to forest tree species by airborne fluoride

(F) has occurred worldwide (Bunce 1979), and

information is available from several studies

conducted in the interior Columbia River basin

(Adams and others 1952, Carlson and Dewey

1971, EPA 1973, Treshow and others 1967). The

principal industrial sources of airborne F are

aluminum smelting, steel manufacture, conversion

of fluorapatite to phosphate and phosphorus in

6 Sum06 is the seasonal sum of all hourly ozone concentrations that are 0.06 ppm or higher.

43
fertilizer production, and glass, ceramic, and

brick production. Natural sources of airborne F

are principally from soil particles, fumaroles, and

volcanoes. The ash from the eruption of Mount

St. Helens contained 8 ppm soluble F (Stoiber and

others 1980) and 400 ppm total F, but this did not

result in F-related injury to forested ecosystems

in the basin.

Several indigenous plant species are sensitive to

atmospheric F, including goatweed, common

barberry, Oregongrape, blueberry, and young

needles of many conifers. One general conclusion

can be made: field observations of plants can be a

good qualitative but usually a poor quantitative

indicator of effects. There has been severe depletion of lichen populations in many cases of

F-pollution (reviewed by Gilbert 1973).

The advent and implementation of new technologies for control of F-emissions within the aluminum industry has greatly reduced F-emissions

within the basin. Emission monitoring and field

surveys still are conducted by aluminum industry

personnel, but we are not aware of ongoing research programs to determine F-induced effects

on forested ecosystems within the basin. The

potential impact of F-emissions to vegetation

presently seems low because the emissions are

limited to a few point sources associated with

aluminum reduction plants within the basin.

In summary, for fluoride and the condition of

terrestrial resources in the basin:

1. The implementation of new technologies for

control of F-emissions within the aluminum

industry has greatly reduced F-emissions within

the basin.

2. Current impacts due to F are likely to be

limited to proximity to the few point sources

within the basin.

Visibility in the Basin

Visibility is an important air resource. Congress

recognized this and included visibility protection

as part of the 1977 Clean Air Act amendments

(U.S. Laws, Statutes 1977). In section 169A,

Congress declared, as a national goal, “the prevention of any future, and the remedying of any

existing, impairment of visibility in mandatory

class I Federal areas which impairment results

from manmade air pollution.”

Visibility degradation can manifest itself in various ways, including discoloration, a change in

the sharpness or clarity of a view, or as a decrease

in the distance one can see. Human-caused air

pollution phenomena affecting visibility are generally categorized as plumes, layered hazes, or

uniform hazes. Plumes are generally coherent

masses of pollutant that either discolor parts of a

scene or affect the sharpness of objects viewed.

Distinct plumes are generally observed within a

few kilometers of a pollutant source. Layered

hazes are similar to plumes, in that they are a distinct mass of pollutant observed in the atmosphere, but their spatial extent is greater and they

may not be visually linked to a nearby source.

Uniform hazes are more ubiquitous masses of

visibility-affecting pollutant; they generally cover

a large geographic area and are well mixed vertically. Uniform hazes usually are formed by a

number of contributing sources, although, individual large sources can dominate under the right

atmospheric conditions. Uniform hazes can be

formed by pollutants traveling over a few to several hundred kilometers. For characterizing visibility over an area such as the interior Columbia

River basin, measurements of uniform haze are

generally used. Localized visibility problems

within the region can be caused by plumes and

layered hazes, but the available measurements

are more appropriate for characterizing uniform

hazes.

The available data for characterizing visibility

conditions in the basin come from the IMPROVE

(Interagency Monitoring of Protected Visual Environments) monitoring network. IMPROVE sites

generally include aerosol and optical measurements. The aerosol sampling is accomplished by

particle collection and sample analysis. View

monitoring is also performed. Three color slides

are taken each day, via automatic camera, to document the appearance of a selected scene.

The aerosol scattering efficiencies differ for different aerosol components. The efficiencies for

hygroscopic aerosols, such as sulfate, nitrate, and

some organic aerosols, differ as functions of relative humidity. The effect of humidity on scattering from hygroscopic aerosols is especially pronounced at high relative humidities; the effect

can be greater than an order of magnitude than if

the same aerosol was dry. For more information

on IMPROVE, see Sisler and others (1993).

44
Available Data

The IMPROVE monitoring stations within the

basin are all near the perimeter of the area:

Columbia River Gorge, Snoqualmie Pass, Crater

Lake National Park, Lassen Volcanic National

Park, Jarbidge Wilderness Area, Yellowstone National Park, and Glacier National Park. There also

is an IMPROVE site at Mount Rainier, which is

just outside of the basin boundary; the actual

monitoring site is at low elevation on the west

side of Mount Rainier National Park. The interior

of the basin is not well characterized, and conditions there may be different from those measured

on the periphery.

Figure 24 shows the contribution of aerosols to

light extinction at the IMPROVE sites around the

basin. Figure 25 displays the same information,

expressed as a percentage. At all sites, organic

aerosol is a major component of the aerosol extinction budget, and at most of the sites sulfate is

also a major contributor. With the exception of

the Columbia River Gorge and Snoqualmie Pass

sites, the contribution of nitrate is slight. The

component identified as soot, sometimes referred

to as light-absorbing carbon, is the third largest

component everywhere except the Columbia

River Gorge site, where it is the largest component. At Jarbidge, coarse aerosols contribute

slightly more to extinction than sulfate, and at

Columbia River Gorge, nitrate is comparable to

sulfate.

Visibility at the sites is quite variable as seen in

figure 26, where visibility is expressed in terms

of standard visual range. The more northerly sites,

Columbia River Gorge, Glacier National Park,

Mount Rainier, and Snoqualmie Pass, have much

lower average visual ranges than the more southerly sites. The southerly sites all have average

standard visual ranges in excess of 130 km, and

all the northerly sites are less than 80 km. The

Jarbidge site exhibits some of the best visibility

conditions of any site in the IMPROVE network,

with an annual average standard visual range of

168 km.

Discussion

To better understand why the northern sites have

poorer average visibility conditions than the

southerly sites, the relative influence of various

fine particles must be examined. All northern sites

have higher concentrations of organic aerosols

and higher levels of sulfate. The annual average

organic concentration is highest at the Glacier National Park site, and the highest sulfate concentration occurs at the Columbia River Gorge site.

Although the concentrations of organics and sulfate are higher at Glacier National Park and

Columbia River Gorge, the highest extinction due

to those elements is at the Mount Rainier site. As

noted earlier, the light scattering efficiency of sulfate, nitrate, and some organics is enhanced at

higher relative humidities. Humidity at the Mount

Rainier site is much higher on average than generally occurs at east-side sites. Therefore the importance of those components to light extinction

also is enhanced, relative to the total mass of

those aerosols. This can be seen by comparing

figure 27 with figure 24. In figure 27, the mass of

sulfate and organics at Mount Rainier is similar

to other sites, but figure 24 shows that the effect

on extinction is much greater.

One of the differences of the three sites along the

northern Cascade Range (Snoqualmie Pass,

Mount Rainier, and Columbia River Gorge), relative to the other sites in the region, is their proximity to the upwind pollution source areas of

western Washington and Portland, OR. This leads

to elevated sulfate and, at Columbia River Gorge

and Snoqualmie Pass, nitrate concentrations. The

Mount Rainier IMPROVE site is located slightly

west of Mount Rainier National Park and at relatively low elevation. The Mount Rainier IMPROVE is likely to be more affected by sources

in the Puget Sound region and the western

Washington lowlands than sites actually located

in the basin. Even though the Snoqualmie Pass

and Columbia River Gorge sites are both within

the basin area, they are each near the boundary

and are at low points in the Cascade Range where

pollutants are channeled from Seattle and

Portland. Major interstate highway routes run

through Snoqualmie Pass and along the Columbia

River. The Columbia River Gorge site also may

be affected by various industrial facilities along

the Columbia River.

45
Figure 24—Light extinction due to aerosol components for the interior Columbia

River basin IMPROVE sites. Columbia River Gorge Scenic Area = CORI, Crater

Lake National Park = CRLA, Glacier National Park = GLAC, Jarbidge Wilderness =

JARB, Mount Rainier National Park = MORA, Snoqualmie Pass = SNPA,

Yellowstone National Park = YELL, Lassen Volcanic National Park = LAVO. ∗ = the

period of record for Columbia River Gorge and Snoqualmie Pass from June 1993

to August 1994.

Figure 25—Percentage of light extinction due to aerosol components for the interior

Columbia River basin IMPROVE sites. Columbia River Gorge Scenic Area = CORI,

Crater Lake National Park = CRLA, Glacier National Park = GLAC, Jarbidge

Wilderness = JARB, Mount Rainier National Park = MORA, Snoqualmie Pass =

SNPA, Yellowstone National Park = YELL, Lassen Volcanic National Park = LAVO.

∗ = the period of record for Columbia River Gorge and Snoqualmie Pass from June

1993 to August 1994.

46
Figure 26—Standard visual range, expressed as an annual average, in

kilometers, for the interior Columbia River basin IMPROVE sites. Columbia

River Gorge Scenic Area = CORI, Crater Lake National Park = CRLA,

Glacier National Park = GLAC, Jarbidge Wilderness = JARB, Mount

Rainier National Park = MORA, Snoqualmie Pass = SNPA, Yellowstone

National Park = YELL, Lassen Volcanic National Park = LAVO. ∗ = the

period of record for Columbia River Gorge and Snoqualmie Pass from

June 1993 to August 1994.

Figure 27—Aerosol extinction budget with organics and soot combined into total carbon for

the interior Columbia River basin IMPROVE sites. Columbia River Gorge Scenic Area =

CORI, Crater Lake National Park = CRLA, Glacier National Park = GLAC, Jarbidge

Wilderness = JARB, Mount Rainier National Park = MORA, Snoqualmie Pass = SNPA,

Yellowstone National Park = YELL, Lassen Volcanic National Park = LAVO. ∗ = the period of

record for Columbia River Gorge and Snoqualmie Pass from June 1993 to August 1994.

47
Although there are elevated nitrate concentrations at Columbia River Gorge and Snoqualmie

Pass, the nitrate aerosol may not be transported

very far into the interior of the interior Columbia

River basin. Ammonium nitrate aerosol is in

equilibrium with its gas phase components and

can revert back to those components. Generally,

cool, moist conditions are more favorable for the

formation of ammonium nitrate aerosol, and

warmer dryer conditions are more favorable for

the gaseous components. Ammonium nitrate

therefore can be somewhat transient in the atmosphere and usually is not measured in high concentrations at sites distant from source areas.

At all the sites in and around the basin, carbon in

its various forms dominates the extinction budget.

Figure 27 displays the same information as figure

25 but combines the organics and soot categories

into “total carbon.” With the exception of the sites

along the northern portion of the Cascade Range,

total carbon accounts for more than 50 percent of

the total aerosol extinction. This has certain implications for forest management practices in the

basin. Carbonaceous aerosols are emitted by forest burning. Dramatic increases in burning are

likely to degrade visibility in the protected areas

of the region. Burning practices will have to be

considered for improvements to be made in visibility conditions.

The data discussed here have been presented as

annual average conditions for comparison among

sites. Depending on the use of the data, other statistical groupings may be more appropriate. For

example, the distribution of aerosols on the worst

visibility days would be worth examining if the

management objective were to remedy some

existing visibility impairment on those days. Conversely, the relative distribution of aerosols on

the best visibility days would be more appropriate

if the management objective were protection of

the cleanest days. Similarly, the visibility conditions also differ by season. If management options

being examined are seasonal in nature, seasonal

visibility values should be determined.

Ecosystems and Resources at

Risk From Air Pollution

Forests

Much of the interior Columbia River basin

includes pine, fir, and spruce species (fig. 28).

These forests are exposed to ozone and deposition

of sulfur and nitrogen compounds. Ponderosa pine

within the basin is likely to be especially sensitive

to ozone and is at high risk of injury if ozone

levels continue to rise. The forests are also at risk

for alteration of growth rates and patterns, soil

acidification, shifts in species composition, and

modification of the effect of natural stresses such

as drought and insect infestation in response to

N- and S- deposition. One of the biggest unknowns relative to the effects of air pollution on

these forests is the status of forest soils and the

effects of N-deposition on nutrient cycling, particularly in forest stands disturbed by fire, pests, and

disease outbreaks.

High-Elevation Lakes and Streams

The EPA is required to prepare an assessment of

the information available to set a standard to protect sensitive ecosystems from damage due to

deposition of acidity, sulfur, and nitrogen compounds. In the 1995 report (EPA 1995), sensitive

aquatic resources were identified in (1) the

Cascade Range in Washington, Oregon, and

California; (2) the Idaho Batholith in Idaho and

Montana; (3) the mountain ranges of northwestern

Wyoming; and (4) the Rocky Mountains in

Colorado.

At present there are no chronically acidified lakes

due to deposition inputs in the basin; however,

many of the sensitive, low-acid neutralizing capacity systems found at high elevations are susceptible to episodic acidification associated with intense rains or spring snowmelt. There is evidence

that N-deposition in rain, snow, and dry fall have

caused small, chronic losses of acid neutralizing

capacity in high-elevation lakes in the West. The

48
LEGEND

Agropyron bunchgrassAlpine tundraAntelope bitterbrush/AspenBarrenBig sagebrushChokecherry/serviceberry/roseCottonwood/willowCropland/hay/pastureEngelmann spruce/subalpine firExotic forbs/annual grassFescue−bunchgrassGrand fir/white firHerbaceous wetlandsInterior Douglas−firInterior ponderosa pineJuniper woodlandsJuniper/sagebrushLimber pineLodgepole pineLow sageMixed conifer woodlandsMountain big sagebrush

Mountain hemlockMountain mahoganyNative forbsOregon white oakPacific ponderosa pinePacific silver fir/Red firSalt desert shrubShrub or herb/treeShrub wetlandsSierra Nevada mixedUrbanWestern redcedar/WaterWestern larchWestern white pineWhitebark pineWhitebark pine/alpineState boundaryColumbia River basinassessment boundary

bluebunch wheatgrass

mountain hemlockregenerationconiferwestern hemlocklarch

Figure 28—Current cover types within the interior Columbia River basin assessment area.

49
EPA’s Western Lake Survey (Eilers and others

1987, Landers and others 1987) detected measurable amounts of nitrate in lakes of northwestern

Wyoming and the Colorado Rocky Mountains

(especially in Front Range locations). These concentrations were sufficiently high to indicate that

these high-elevation watersheds have little remaining capacity to absorb nitrogen in deposition

(EPA 1995).

Arid Lands

Mangis and others (1991) review the possible effects of air pollution and deposition on resources

found in arid lands. Areas of eastern Oregon and

Washington and south-central Idaho can be considered part of the Great Basin and Intermountain

desert and semidesert ecoregions, where little research or monitoring has been done to determine

levels of air pollutants and their effects. These

parts of the basin include salt desert shrub and

sagebrush-dominated landscapes (see the southwest section of fig. 28) and depend on the integrity of cryptogamic crusts for soil stabilization.

Additional information on exposure of these ecosystems to air pollutants and deposition is needed

with special attention to the cryptogams.

Class I Areas

Federal land managers of class I wildernesses and

parks (fig. 1) have an “affirmative responsibility

to protect the air quality related values;” e.g., visibility, vegetation, water, soil, fauna, and ecosystem processes, from adverse effects of air

pollution (40 CFR 52.21(p)(2)). High-elevation

vegetation may be particularly at risk from ozone

because ozone concentrations are often highest at

these elevations. For a more detailed discussion

of class I areas managed by the National Park

Service in the Pacific Northwest, refer to Eilers

and others (1994); a compilation of information

on U.S. Department of Agriculture Forest Service

class I areas can be found in Peterson and others

(1992a, 1992b) and Stanford and others (1997).

Research, Development, and

Assessment

Future air quality assessments for the interior

Columbia River basin would benefit from:

1. Integration of criteria air pollutants and deposition information with information on other pollutants of interest (for example, organics and

particles from wildfires, pesticides and herbicide

transport, and toxic air contaminants identified in

the 1990 Clean Air Act amendments [U.S. Laws,

Statutes 1990]).

2. Continued and augmented monitoring of pollutants important to ecosystem function in the

basin, including (1) high-elevation monitoring of

rain and snow with emphasis on quantification of

nitrogen species, (2) dry deposition monitoring,

(3) ozone monitoring in remote areas using both

continuous and integrated methods, (4) preliminary assessment of levels of persistent organic

pollutants and mercury, and (5) improved estimates of nonpoint source NOx emissions.

3. Creation of an air quality related value inventory for each of the class I areas and other sensitive ecosystems and watersheds within the basin.

Once this inventory is compiled, Federal and state

agency personnel could devise an air quality related value monitoring program to detect changes

in response variables in the sensitive ecosystems.

Before this monitoring program is implemented,

more studies would be needed to determine levels

of pollutants that might affect sensitive end points

(for example, fumigation experiments on representative vascular and nonvascular plant species,

nitrogen additions to determine thresholds to prevent changes in terrestrial community structure,

and acidification and nitrogen addition experiments to determine degree of change in surface

water chemistry and biota).

50
4. Discussion of population growth, planned development activities, and the projection of future

emissions, transport, transformation, and deposition and the effects of these increases in emissions

on human health and resource degradation. Ecosystem level effects and impact on air quality related values in wilderness areas and national

parks may need special attention.

5. Extensive information about sensitive processes, populations, and ecosystems found in the

basin that are at risk from air pollutants and deposition is lacking. These include forests, highelevation lakes and streams, and arid lands. More

information on the potential impacts of air pollutants and deposition on ecological and biological

resources including forests, high-elevation lakes

and streams, and arid lands would benefit this assessment. This can be accomplished only with the

collection of ecosystemwide data on current status

and the prediction of future condition under different air quality scenarios. This type of prediction will be furthered through the use of models

and experimental manipulations in the field. This

level of research and monitoring will require a

commitment of funds and the cooperation and

coordination among agencies with interest in air

quality and ecosystem integrity.

51
Definition of Terms Used

Acid neutralizing capacity: A quantitative measure of the ability of water to neutralize acid. In

the basin, acid neutralizing capacity is almost entirely due to the bicarbonate ion (HCO3

-

). Units

commonly used are μeq L-1 (microequivalents

per liter) and mg L-1 CaCO3 (milligrams per

liter calcium carbonate). 1 mg L-1 CaCO3 = 20

μeq L-1.

Acidification: The loss of some or all acid

neutralizing capacity due to reaction with acid.

Acidic lake: One with acid neutralizing capacity

of zero or less (negative acid neutralizing capacity

corresponds to acidity).

Aerosol: Microscopic solid or liquid particles in

a gaseous medium.

Area source: Any small source of nonnatural air

pollution that is released over a relatively small

area but which cannot be classified as a point

source.

Class I areas: All international parks, national

parks greater than 2430 ha (6,000 acres), and national wilderness areas greater than 2025 ha

(5,000 acres) that existed on August 7, 1977,

when the 1977 Clean Air Act amendments (U.S.

Laws, Statutes 1977) were passed. This class

provides the most protection to pristine lands by

severely limiting the amount of air pollution that

can be added to an area.

Criteria pollutant: The 1977 Clean Air Act

amendments (U.S. Laws, Statutes 1977) requires

EPA to set standards for certain pollutants known

to be hazardous to human health. The EPA has

identified and set standards for six pollutants:

ozone, carbon monoxide, particulate matter,

sulfur dioxide, lead, and nitrogen oxides.

Cryptogam: A plant (such as a fern, moss, alga,

or fungus) reproducing by spores and not producing flowers or seed.

Dry deposition: Removal of gaseous and particulate species from the atmosphere to terrestrial

and aquatic ecosystems.

IMPROVE: Interagency Monitoring of Protected

Visual Environments was initiated to fulfill the

national goal of preventing any future and remedying existing visibility impairment in national

parks and wilderness areas. The National Park

Service, Forest Service, Fish and Wildlife Service, Bureau of Land Management, and Environmental Protection Agency coordinate to meet this

goal.

National Atmospheric Deposition Program

(NADP) network: This network monitors geographical and temporal trends in the chemical

composition of rain and snow, in support of research on effects, particularly on aquatic and

terrestrial ecosystems.

National Dry Deposition Network (NDDN):

This network monitors the magnitude, spatial

variability, and trends in dry deposition of ozone

and acidic particles and gases.

Nitrate: A compound containing nitrogen that

can exist in the atmosphere or as a dissolved gas

in water and that can have harmful effects on

humans and animals.

Nitrogen oxides (NOx): Product of combustion

from transportation and stationary sources and a

major contributor to acid deposition and the formation of ground level ozone in the troposphere.

Nonattainment area: An area deemed by EPA

or a State air regulatory agency as not meeting

the ambient air quality standard for a specific

pollutant.

Occult deposition: Deposition not easily identified or measured, such as fog.

Particulates: Any material, except water or gas

in a chemically uncombined form, that is or has

been airborne and exists as a liquid or solid at

standard temperature and pressure conditions.

Minute particles of dust, fly ash, fumes, and

oxides of various metals are examples of

particulates.

52
pH: A measure of the acidity or alkalinity of a

liquid or solid material measured as the negative

log of the hydrogen ion; -Log10[H+

]. Typical

rainwater measures about 5.5 pH, lemon juice

about 2 pH, and ammonia about 11 pH. Common

pH conversions:

pH of 4 = 100 μeq L-1 of acidity

pH of 5 = 10 μeq L-1 of acidity

pH of 6 = 1 μeq L-1 of acidity

Point source: A stationary location or fixed

facility from which pollutants are discharged or

emitted.

Pphm: Parts per hundred million.

Radionuclide: Radioactive element characterized by its atomic mass and atomic number;

can be human-made or naturally occurring.

Sensitivity: A subjectively defined measure of

whether a lake or stream has enough acid neutralizing capacity to neutralize additional acid. If the

acid neutralizing capacity is large relative to the

anticipated amount of acid, the lake or stream is

said to not be sensitive to acidification. If, however, acid neutralizing capacity is lower than the

specified amount of acid, the lake or stream is

said to be very sensitive. This measure is useful

in broadly characterizing whether populations of

lakes or streams are at risk.

Standard visual range (SVR): The distance at

which a large black object just disappears on the

horizon.

Stomata: Small pores in the epidermis of the

leaf, to provide for the entry of carbon dioxide

and the discharge of oxygen and water vapor.

Sulfates: Aerosols that have origins in the gas-toaerosol conversion of sulfur dioxide; e.g., sulfuric

acid and ammonium sulfate.

Sulfur dioxide (SO2): A heavy, pungent, colorless, gaseous air pollutant formed primarily by

industrial fossil fuel combustion processes.

Volatile organic compounds (VOC): Organic

compounds that participate in atmospheric

photochemical reactions.

Conversion Table

When you know: Multiply by: To find:

Millimeters (mm) 0.039 Inches

Centimeters (cm) 0.394 Inches

Meters (m) 3.281 Feet

Kilometers (km) 0.621 Miles

Kilograms (kg) 2.205 Pounds

Hectares (ha) 2.471 Acres

Kilograms/hectare 0.893 Pounds

(kg/ha) per acre

Liters (L) 0.265 Gallons

Milligrams (mg) 35.27 Ounces

Milligrams/liter 1.0 Parts/million

(mg/l) (ppm)

Tons (U.S.) 0.907 Tonnes

Tons (U.S.) per acre 2.24 Megagrams

per hectare

53
Literature Cited

Aber. J.; Knadelhoffer, J.; Steudler, P.; Melillo, J. 1989. Nitrogen saturation in northern forested

ecosystems. Bioscience. 39: 378-386.

Adams, D.F.; Mayhew, D.J.; Gnagy, R.M. [and others]. 1952. Atmospheric pollution in the

ponderosa pine blight area, Spokane County, Washington. Industrial Engineering and Chemistry.

44: 1356-1365.

Andersen, C.P.; Hogsett, W.E.; Wessling, R.; Plocher, M. 1991. Ozone decreases spring root

growth and root carbohydrate content in ponderosa pine the year following exposure. Canadian

Journal of Forest Research. 21: 1288-1291.

Anderson, I.C.; Poth, M.A. 1989. Semiannual losses of nitrogen as NO and N2O from unburned and

burned chaparral. Global Biogeochemical Cycles. 3(2): 121-135.

Böhm, M. 1992. Air quality and deposition. In: Olson, R.K.; Binkley, D.; Böhm, M., eds. The

response of western forests to air pollution. New York: Springer-Verlag: 63-152.

Böhm, M.; McCune, B.; Vandetta, T. 1995. Ozone regimes in or near forests of the Western United

States. I: regional patterns. Journal Air and Waste Management Association. 45: 235-246.

Bormann, F.H.; Likens, G.E.; Melillo, J.M. 1977. Nitrogen budget for an aggrading northern

hardwood forest ecosystem. Science. 196: 981-983.

Bowden, W.B.; Bormann, F.H. 1986. Transport and loss of nitrous oxide in soil water after forest

clear-cutting. Science. 233: 867-869.

Brimblecombe, P.; Hammer, C.; Rodhe, H. [and others]. 1989. Human influence on the sulfur

cycle. In: Brimblecombe, P.; Lein, A.Y., eds. Evolution of the biogeochemical sulfur cycle:

SCOPE 39. Chichester, NY: John Wiley and Sons: 77-121.

Bunce, H.W.F. 1979. Fluoride emissions and forest growth. Journal Air Pollution Control

Association. 29(6): 642-643.

Carlson, C.E.; Dewey, J.E. 1971. Environmental pollution by fluorides in Flathead National Forest

and Glacier National Park. Missoula, MT: U.S. Department of Agriculture, Forest Service,

Northern Region, Division of State and Private Forestry. 57 p.

Chameides, W.L.; Kasibhatla, P.S.; Yienger, J.; Levy, H., II. 1994. Growth of continental-scale

metro-agro-plexes, regional ozone pollution, and world food production. Science. 264: 74-77.

Charles, D., ed. 1991. Acidic deposition and aquatic ecosystems. New York: Springer-Verlag. 747 p.

Charlson, R.J.; Anderson, T.L.; McDuff, R.E. 1992. The sulfur cycle. In: Butcher, S.S.; Charlson,

R.J.; Orians, G.H.; Wolfe, G.V., eds. Global biogeochemical cycles. London: Academic Press;

Harcourt Brace and Co: 285-300.

Clarke, J.F.; Edgerton, E.S. 1992. Dry deposition flux calculations for the National Dry Deposition

Network. Research Triangle Park, NC: [Publisher unknown]; report to the Environmental

Protection Agency, AREAL. 91 p.

Cobb, F.W., Jr.; Stark, R.W. 1970. Decline and mortality of smog injured ponderosa pine. Journal

of Forestry. 68: 147-148.

54
Corn, P.S.; Vertucci, F.A. 1992. Descriptive risk assessment of the effects of acidic deposition on

Rocky Mountain amphibians. Journal of Herpetology. 26: 361-369.

Davidson, E.A. 1991. Fluxes of nitrous oxide and nitric oxide from terrestrial ecosystems. In: Rogers,

John E.; Whitman, William B., eds. Microbial production and consumption of green house gases:

methane, nitrogen oxides, and halomethanes. Washington, DC: American Society of Microbiology.

Davis, D.D.; Wilhour, R.G. 1976. Susceptibility of woody plants to sulfur dioxide and

photochemical oxidants—a literature review. Ecol. Res. Ser. EPA-600/3-76-102. Corvallis, OR:

U.S. Environmental Protection Agency.

Edmonds, R.L.; Basabe, F.A. 1989. Ozone concentrations above a Douglas-fir forest canopy in

western Washington, U.S.A. Atmospheric Environment. 23(3): 625-629.

Eilers, J.; Rose, C.; Sullivan, T. 1994. Status of air quality and effects of atmospheric pollutants on

ecosystems in the Pacific Northwest Region of the National Park Service. Tech. Rep.

NPS/NRAQD/NRTR-94/160. Lakewood, CO. National Park Service. 259 p.

Eilers, J.M.; Kanciruk, P.; McCord, R.A. [and others]. 1987. Western lake survey phase I:

characteristics of lakes in the Western United States. Volume II: Data compendium for selected

physical and chemical variables. EPA/600/3-86/054b. Washington, DC: U.S. Environmental

Protection Agency. 492 p.

Ellenberg, H. 1988. Floristic changes due to nitrogen deposition in central Europe. In: Nilsson, J,;

Grennfelt, P., eds. Critical loads for sulphur and nitrogen: report from a workshop; 1988 March;

Skokloster, Sweden. Copenhagen, Denmark: Nordic Council of Ministers: 375-383.

Environmental Protection Agency. 1973. Fluoride in Glacier National Park: a field investigation.

EPA-908/1-73-001. [Place of publication unknown].

Environmental Protection Agency. 1993. Air quality criteria for oxides of nitrogen: vol. II.

EPA-600/8-91/049bF. Research Triangle Park, NC.

Environmental Protection Agency. 1994a. Deposition of air pollutants to the great waters: first

report to Congress. [Place of publication unknown]; report; contract EPA-453/R-93-055. 89 p.

Environmental Protection Agency. 1994b. National air pollutant emission trends, 1900-1993.

EPA-454/R-94-027. Research Triangle Park, NC: Office of Air Quality Planning and Standards.

Environmental Protection Agency. 1994c. The EPA great waters program: an introduction to the

issues and the ecosystems. [Place of publication unknown]; report; contract EPA-453/B-94/030.

Environmental Protection Agency. 1995. Acid deposition standard feasibility study: report to

Congress. [Place of publication unknown]; report; contract EPA 430-R-95-001a. 120 p.

Fenn, M.E.; Bytnerowicz, A. 1993. Dry deposition of nitrogen and sulfur to ponderosa and Jeffrey

pine in the San Bernardino National Forest in southern California mountain forest smog receptor

site. Environmental Pollution. 81: 277-285.

Ferguson, S.A. 1997. A climate-change scenario for the Columbia River basin. Res. Pap.

PNW-RP-499. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station. 9 p. (Quigley, Thomas M., ed.; Interior Columbia River Basin Ecosystem

Management Project: scientific assessment).

55
Ferguson, S.A. 1998. Air quality climate in the Columbia River basin. Gen. Tech. Rep.

PNW-GTR-434. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station. 23 p. (Quigley, Thomas M., ed.; Interior Columbia River Basin Ecosystem

Management Project: scientific assessment).

Field, C.; Mooney, H.A. 1986. The photosynthesis-nitrogen relationship in wild plants. In: Givnish,

T.J., ed. On the economy of plant form and function. New York: Cambridge University Press:

25-55.

Filip, G.M. 1994. Forest health decline in central Oregon: a 13-year case study. Northwest Science.

68: 233-240.

Gilbert, O.L. 1973. The effect of airborne fluorides. In: Ferry, B.W.; Baddeley, M.S.; Hawksworth,

D.L., eds. Air pollution and lichens. Toronto: University of Toronto Press: 176-191.

Gray, R.H. 1995. Ecosystem monitoring and protected areas: the Hanford Reservation. In: Herman,

T.; Bondrup-Nielsen, S.; Willison, J.; Munro, N., eds. Ecosystem monitoring and protected areas:

Proceedings of the 2d international conference on science and the management of protected areas;

[dates of meeting unknown]; Wolfville, NS. [Place of publication unknown]: [Publisher unknown]:

[pages unknown].

Harte, J.; Hoffman, E. 1989. Possible effects of acidic deposition on a Rocky Mountain population

of the tiger salamander Ambystoma tigrinum. Conservation Biology. 3: 149-158.

Harward, M.; Treshow, M. 1975. Impact of ozone on the growth and reproduction of understorey

plants in the aspen zone of Western U.S.A. Environmental Conservation. 2(1): 17-23.

Heck, W.W.; Adams, R.M.; Cure, W.W. [and others]. 1983. A reassessment of crop loss from

ozone. Environmental Science and Technology. 17: 572A-581A.

Heck, W.W.; Tingey, D.T. 1979. Nitrogen dioxide: time-concentration model to predict acute foliar

injury. EPA Rep. APTD-68-6. Corvallis, OR: U.S. Environmental Protection Agency, Corvallis

Environmental Research Laboratory. Available from: National Technical Information Service,

5285 Port Royal Road, Springfield, VA 22161; [cost unknown] PB-195151.

Hendrey, G.R.; Galloway, J.N.; Norton, S.A. [and others]. 1980. Geological and hydrochemical

sensitivity of the Eastern United States to acid precipitation. EPA/600/3-80/024. Corvallis, OR:

U.S. Environmental Protection Agency.

Hogsett, W.E.; Herstrom, A.A.; Laurence, J.A. [and others]. 1993. Risk characterization of

tropospheric ozone to forests. In: Proceedings of the 4th US/Dutch international symposium:

Comparative risk analysis and priority setting for air pollution issues; 1993 June; [Place of meeting

unknown]. Pittsburgh, PA: Air and Waste Management Association: [pages unknown].

Hogsett, W.E; Tingey, D.T.; Hendricks, C.; Rossi, D. 1989. Sensitivity of western conifers to SO2

and season interaction of acid fog and ozone. In: Olson, R.K.; Lefohn, A.S., eds. Transactions,

symposium on the effects of air pollution on western forests; 1989 June; Anaheim, CA. Pittsburgh,

PA: Air and Waste Management Association: 469-491.

Hogsett, W.E.; Tingey, D.T.; Lee, E.H. 1988. Ozone exposure indices: concepts for development

and evaluation of their use. In: Heck, W.W.; Taylor, O.C.; Tingey, D.T., eds. Assessment of crop

loss from air pollutants. New York: Elsevier Applied Science: 107-138.

56
Ingersoll, G. 1995. Maximum-accumulation snowpack chemistry at selected sites in northwestern

Colorado during spring 1994. Denver, CO: U.S. Department of the Interior, Geological Survey;

open file report 95-139. 14 p.

Johnson, D.; Lindberg, S., eds. 1992. Atmospheric deposition and forest nutrient cycling. New

York: Springer-Verlag. 707 p.

Joseph, D.; Flores, M. 1993. Statistical summary of ozone measurements in the National Park

System, 1981-1991. Volume II: Quick look yearly and growing season frequency distribution

reports. Tech. Rep. NPS/NRTR-93/111. Lakewood, CO: National Park Service. 255 p.

Klopateck, J. 1987. Nitrogen mineralization and nitrification in mineral soils of pinyon-juniper

ecosystems. Soil Science Society America Journal. 51: 453-457.

Kohut, R.J.; Amundson, R.G.; Laurence, J.A. [and others]. 1987. Effects of ozone and sulfur

dioxide on yield of winter wheat. Phytopathology. 77: 71-74.

Kress, L.W.; Miller, J.E.; Smith, H.J. 1987. Impact of ozone on winter wheat yield. Environmental

Experimental Botany. 25: 211-228.

Laird, L.D.; Taylor, H.E.; Kennedy, V.C. 1986. Snow chemistry of the Cascade-Sierra Nevada

mountains. Environmental Science and Technology. 20: 275-290.

Landers, D.H.; Eilers, J.M.; Brakke, D.F. [and others]. 1987. Characteristics of lakes in the

Western United States. Volume I: Population descriptions and physio-chemical relationships.

EPA/600/3-86/054a. Washington, DC: U.S. Environmental Protection Agency. 176 p.

Laurence, J.A.; Amundson, R.G.; Friend, A.L. [and others] 1994. Allocation of carbon in plants

under stress: and analysis of the ROPIS experiments. Journal Environmental Quality. 23: 412-417.

Lefohn, A.S. 1992. Surface level ozone exposures and their effects on vegetation. Chelsea, MI: Lewis

Publishing. 366 p.

Lefohn, A.S.; Lucier, A.A. 1991. Spatial and temporal variability of ozone in forested areas of the

United States and Canada: 1978-1988. Journal Air and Waste Management Association. 41(5):

694-701.

Little, Elbert L., Jr. 1979. Checklist of United States trees (native and naturalized). Agric. Handb.

541. Washington DC: U.S. Department of Agriculture. 375 p.

Logan, J. 1982. Nitrogen oxides in the troposphere: global and regional budgets. Journal of

Geophysical Research. 88: 10785-10807.

Ludwig, J.D.; Webber, D.B.; Olson, K.B.; Garcia, S.R. 1980. Air quality measurements in the coal

fired power plant environment of Colstrip, Montana. Atmospheric Environment. 14: 523-532.

Lynch, J.; Grimm, J.; Bowersox, V. 1995. Trends in precipitation chemistry in the United States: a

national perspective, 1980-1992. Atmospheric Environment. 29: 1231-1246.

Malm, W. 1992. Characteristics and origins of haze in the continental United States. Earth-Science

Reviews. 33: 1-36.

Malm, W.; Gebhart, K.; Molenar, J. [and others]. 1994. Examining the relationship between

atmospheric aerosols and light extinction at Mount Rainier and North Cascades National Parks.

Atmospheric Environment. 28: 347-360.

57
Mangis, D.; Baron, J.; Stolte, K. 1991. Acid rain and air pollution in desert park areas. In:

Proceedings and management recommendations of a workshop; 1991 November; [location of

meeting unknown]. Tech. Rep. NPS/NRAQD/NRTR-91/02. Lakewood, CO: National Park

Service: [pages unknown].

Matson, P.A.; Gower S.T.; Volkmann, C. [and others]. 1987. Soil nitrogen cycling and nitrous

oxide flux in a Rocky Mountain Douglas-fir forest: effects of fertilization, irrigation and carbon

addition. Biogeochemistry. 18: 101-117.

Melack, J.M.; Stoddard, J.L. 1991. Sierra Nevada, California. In: Charles, D.F., ed. Acidic

deposition and aquatic ecosystems: regional case studies. New York: Springer-Verlag: 503-530.

Miller, Paul R. 1973. Oxidant-induced community change in a mixed conifer forest. In: Air pollution

damage to vegetation. Advances Chem. Ser. 112. [Place of publication unknown]: American

Chemical Society: 101-117.

Miller, Paul R.; McBride, Joe R.; Schilling, Susan L.; Gomez, Anthony P. 1989. Trend of ozone

damage to conifer forests between 1974 and 1988 in the San Bernardino Mountains of southern

California. In: Olson, R.K.; Lefohn, A.S., eds. Transactions, Symposium on the effects of air

pollution on western forests; 1989 June; Anaheim, CA. Pittsburgh, PA: Air and Waste

Management Association: 309-323.

Moller, D. 1984. Estimation of the global man-made sulfur emissions. Atmospheric Environment. 18:

19-27.

Mooney, H.A.; Vitousek, P.M.; Matson, P.A. 1987. Exchange of materials between terrestrial

ecosystems and the atmosphere. Science. 238: 926-932.

National Acid Precipitation Assessment Program [NAPAP]. 1991. Acidic deposition: state of

science and technology reports. Washington, DC: United States Government Printing Office. Vol.

1-4.

National Atmospheric Deposition Program [NADP]. 1993. NADP/NTN annual data summary:

precipitation chemistry in the United States: 1992. Fort Collins, CO: Natural Resource Ecology

Laboratory, Colorado State University. 465 p.

Nelson, P.O. 1991. Cascade mountains. In: Charles, D.F., ed. Acidic deposition and aquatic

ecosystems: regional case studies. New York: Springer-Verlag: 531-566.

Oregon Department of Agriculture. 1994. Summary of fertilizer, agricultural minerals and limes on

which tonnage taxes were paid in Oregon for the period January 1, 1993 to December 31, 1993.

[Place of publication unknown], OR.

Pell, E.J.; Pearson, N.S.; Vinten-Johansen, C. 1988. Qualitative and quantitative effects of ozone

and/or sulfur dioxide on field-grown potato plants. Environmental Pollution. 53: 171-186.

Pell, E.J.; Temple, P.; Friend, A. [and others]. 1994. Compensation: how it influences plant

response to stress singly and in combination. Journal of Environmental Quality. 23: 429-436.

Peterson, D.L.; Schmoldt, D.L; Eilers, J.M. [and others]. 1992a. Guidelines for evaluating air

pollution impacts on class I wilderness areas in Calfornia. Gen. Tech. Rep. PSW-GTR-136.

Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.

34 p.

58
Peterson, Janice; Schmoldt, Daniel; Peterson, David [and others]. 1992b. Guidelines for

evaluating air pollution impacts on class I wilderness areas in the Pacific Northwest. Gen. Tech.

Rep. PNW-GTR-299. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific

Northwest Research Station. 83 p.

Rasmussen, P.E. 1991. Nitrogen movement and recovery in dryland winter wheat. In: Proceedings,

42d annual Far West regional fertilizer conference; 1991 July 8-9; Coeur d’Alene, ID. [Place of

publication unknown]: [publisher unknown].

Reich, P.B. 1987. Quantifying plant response to ozone: a unifying theory. Tree Physiology. 3: 63-91.

Schulze, E.D.; Kelliher, F.M.; Korner, C. [and others]. 1994. Relationships among maximum

stomatal conductance, ecosystem surface conductance, carbon assimilation rate, and plant nitrogen

nutrition: a global ecology scaling exercise. Annual Review of Ecology and Systematics. 25:

629-660.

Sheffer, T.C.; Hedgcock, G.C. 1955. Injury to northwestern trees by sulfur dioxide from smelters.

Tech. Bull. 1117. [Place of publication unknown]: U.S. Department of Agriculture, Forest Service.

49 p.

Sisler, J.F.; Huffman, D.; Latimer, D., 1993. Spatial and temporal patterns and the chemical

composition of the haze in the United States: an analysis of data from the IMPROVE network,

1988-1991. ISSN 0737-5352-26. Fort Collins, CO: Colorado State University, Cooperative

Institute for Research in the Atmosphere.

Stanford, J.; Acheson, A.; Brakke, D.; [and others]. 1997. A screening procedure to evaluate air

pollution effects in Region 1 wilderness areas, 1991. Gen. Tech. Rep. RM-GTR-294. Fort Collins,

CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 34 p.

Stoddard, J. 1994. Long-term changes in watershed retention of nitrogen: its causes and aquatic

consequences. In: Baker, L.A. Environmental chemistry of lakes and reservoirs. Advances Chem.

Ser. 237. Washington DC: American Chemical Society.

Stoiber, R.E.; Williams, S.N.; Malinconica, L.L. 1980. Mount St. Helens, Washington, 1980

volcanic eruption: magmatic gas component during the first 16 days. Science. 208: 1258-1259.

Stolte, K.; Mangis, D.; Doty, R.; Tonnessen, K. 1993. Lichens as bioindicators of air quality. Gen.

Tech. Rep. RM-224. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky

Mountain Forest and Range Experiment Station. 131 p.

Stolte, K.W.; Flores, M.I.; Mangis, D.R.; Joseph, D.B. 1992. Tropospheric ozone exposures and

ozone injury on sensitive pine species in the Sierra Nevada of California. In: Tropospheric ozone

and the environment. II: Effects, modeling and control. Transactions Series 20. Pittsburgh, PA: Air

and Waste Management Association: 637-662.

Taylor, G.E. 1978. Genetic analysis of ecotypic differentiation of an annual plant species, Geranium

carolinianum L., in response to sulfur dioxide. Botanical Gazette. 139: 362-368.

Taylor, G.E.; Johnson, D.W.; Andersen, C.P. 1994. Air pollution and forest ecosystems: a regional

to global perspective. Ecological Applications. 4(4): 662-689.

59
Taylor, G.E., Jr.; Pitelka, L.F.; Clegg, M.T., eds. 1991. Ecological genetics and air pollution. New

York: Springer-Verlag.

Treshow, M.; Anderson, F.K.; Harner, F. 1967. Responses of Douglas-fir to elevated atmospheric

fluorides. Forest Science. 13(2): 114-120.

Treshow, M.; Stewart, D. 1973. Ozone sensitivity of plants in natural communities. Biological Conversation. 5(3): 210-213.

Turk, J. 1995. Effects of energy resource development on lakes—What do we need to know? In:

Carter, L.M.H. Energy and the environment—application of geosciences to decision-making. Circ.

1108. Washington, DC: U.S. Department of Interior, Geological Survey.

Turk, J.; Adams, D.B. 1983. Sensitivity to acidification of lakes in the Flattops Wilderness Area in

Colorado. Water Resources Research. 19: 346-350.

Turk, J.; Spahr, N. 1991. Rocky Mountains. In: Charles, D., ed. Acidic deposition and aquatic ecosystems: regional case studies. New York: Springer-Verlag: 471-502.

U.S. Department of Agriculture, Natural Resources Conservation Service [USDA-NRCS]. 1998.

USDA Natural Resources Conservation Service PLANTS National Database. Available HTTP:

http://plants.usda.gov/plants.

U.S. Laws, Statutes, etc.; Public Law 95-95. Clean Air Act as Amended August 1977. 42 U.S.C.

1857 et seq.

U.S. Laws, Statutes, etc.; Public Law 101-549. Clean Air Act as Amended Nov. 1990. 104 Stat.

2399.

Washington Department of Agriculture. 1994. July 01, 1992-June 30, 1993 annual tonnage reports

commercial fertilizers including limes. Olympia, WA: Pesticide Management Division.

Watras, C.; Huckabee, J., eds. 1994. Mercury pollution: integration and synthesis. Chelsea, MI:

Lewis Publishers.

60
Appendix 1

Class I Areas Within the Interior Columbia River Basin1

Class I area State Managing agency Area

Ha Acres

Caribou Wilderness CA Forest Service 7 727 19,080

Lava Beds Wilderness CA National Park Service 11 599 28,640

South Warner Wilderness CA Forest Service 27 745 68,507

Thousand Lakes Wilderness CA Forest Service 6 356 15,695

Marble Mountain Wilderness CA Forest Service 86 566 213,743

Lassen Volcanic National Park CA National Park Service 42 849 105,800

Hell’s Canyon Wilderness2 ID Forest Service 33 939 83,800

Sawtooth Wilderness ID Forest Service 87 635 216,383

Selway-Bitterroot Wilderness3 ID Forest Service 400 127 988,700

Craters of the Moon

National Monument ID National Park Service 17 513 43,243

Yellowstone National Park4 ID National Park Service 12 753 31,488

Flathead Reservation MT Tribal 505 440 1,248,000

Anaconda Pintler Wilderness MT Forest Service 63 910 157,803

Bob Marshall Wilderness MT Forest Service 384 750 950,000

Cabinet Mountains Wilderness MT Forest Service 38 780 94,272

Gates of the Mountains

Wilderness MT Forest Service 11 568 28,562

Scapegoat Wilderness MT Forest Service 96 914 239,295

Selway-Bitterroot Wilderness3 MT Forest Service 101 956 251,930

Yellowstone National Park4 MT National Park Service 67 888 167,624

Glacier National Park MT National Park Service 410 103 1,012,599

1 From 40 CFR 81.400, revised July 1, 1994 and tribal sources.

2 Hells Canyon Wilderness, 78 043 ha (192,700 acres) overall, of which 44 105 ha (108,900 acres) are in Oregon and 33 939

ha (83,800 acres) are in Idaho.

3 Selway-Bitterroot Wilderness, 502 083 ha (1,240,630 acres) overall, of which 400 127 ha (988,700 acres) are in Idaho and

101 930 ha (251,930 acres) are in Montana.

4 Yellowstone National Park, 898 993 ha (2,219,737 overall, of which 818 353 ha (2,020,625 acres) are in Wyoming, 67 888

ha (167,624 acres) are in Montana, and 12 753 ha (31,488 acres) are in Idaho.

61
Red Rock Lakes Wilderness MT Fish and Wildlife Service 13 102 32,350

Jarbidge Wilderness NV Forest Service 26 190 64,667

Eagle Cap Wilderness OR Forest Service 118 858 293,476

Gearhart Mountain Wilderness OR Forest Service 7 577 18,709

Hell’s Canyon Wilderness3 OR Forest Service 44 105 108,900

Mount Hood Wilderness OR Forest Service 5 735 14,160

Mount Washington Wilderness OR Forest Service 19 487 48,116

Strawberry Wilderness OR Forest Service 13 366 33,003

Three Sisters Wilderness OR Forest Service 80 960 199,902

Crater Lake National Park OR National Park Service 64 918 160,290

Alpine Lakes Wilderness WA Forest Service 122 921 303,508

Glacier Peak Wilderness WA Forest Service 188 024 464,258

Goat Rocks Wilderness WA Forest Service 33 485 82,680

Mount Adams Wilderness WA Forest Service 13 104 32,356

Mount Rainier National Park WA National Park Service 95 272 235,239

North Cascades National Park WA National Park Service 203 827 503,277

Pasayten Wilderness WA Forest Service 204 737 505,524

Spokane Reservation WA Tribal 54 004 133,344

Bridger Wilderness WY Forest Service 158 825 392,160

Fitzpatrick Wilderness WY Forest Service 77 397 191,103

Grand Teton National Park WY National Park Service 123 729 305,504

North Absaroka Wilderness WY Forest Service 142 197 351,104

Teton Wilderness WY Forest Service 225 711 557,311

Washikie Wilderness WY Forest Service 278 067 686,584

Yellowstone National Park4 WY National Park Service 818 353 2,020,625

62
Appendix 2

Nonattainment Areas Within or Near the Interior Columbia River Basin1

State Nonattainment Area Pollutant

California Lake Tahoe North Shore area:

Placer County (part) Carbon monoxide

Lake Tahoe South Shore area:

El Dorado County (part) Carbon monoxide

Idaho Boise, Northern Ada County area Carbon monoxide

Boise, Ada County PM-10

Shoshone County (part) PM-10

City of Pinehurst PM-10

Pocatelllo area PM-10

Sandpoint area, Bonner County PM-10

Montana Missoula County (part) Carbon monoxide

Flathead County (part) PM-10

Columbia Falls and vicinity PM-10

City of Whitefish and vicinity PM-10

Libby and vicinity PM-10

Ronan PM-10

Polson PM-10

Missoula and vicinity PM-10

Thompson Falls and vicinity PM-10

Helena Sulfur dioxide

Nevada Lake Tahoe area:

Carson City County (part) Carbon monoxide

Douglas County (part) Carbon monoxide

Washoe County (part) Carbon monoxide

Reno area:

Washoe County (part) Carbon monoxide

Washoe County Ozone

Reno planning area PM-10

Oregon Lakeview (urban growth boundary area) PM-10

La Grande (area within the urban

growth boundary area) PM-10

1 From 40 CFR 81.300 revised July 1, 1994.

63
Utah Ogden Carbon monoxide

Provo Carbon monoxide

Salt Lake City Carbon monoxide

Davis County Ozone

Salt Lake County Ozone

Salt Lake County PM-10

Utah County PM-10

Salt Lake County Sulfur dioxide

Toole County (part) Sulfur dioxide

64
Appendix 3

Species List1

Common name Scientific name

Alder, mountain Alnus incana (L.) Moench

Alder, thinleaf Alnus incana ssp. tenuifolia (Nutt.) Breitung

Apple Malus Mill.

Apricot Prunus L.

Aspen, quaking Populus tremuloides Michx.

Barberry, common Berberis vulgaris L.

Birch, water Betula occidentalis var. fecunda Fern.

Birch, western paper Betula papyrifera var. commutata (Regel) Fern.

Buckbrush Ceanothus cuneatus (Hook.) Nutt.

Buffaloberry, russet Shepherdia canadensis (L.) Nutt.

Ceanothus, redstem Ceanothus sanguineus Pursh

Ceanothus, snowbrush Ceanothus velutinus Dougl. ex Hook.

Cedar, western red Thuja plicata Donn. ex D. Don

Cherry Prunus L.

Cherry, bitter Prunus emarginata Dougl. ex Eaton

Chokecherry, common Prunus virginiana L.

Cottonwood, black Populus trichocarpa Torr. & Gray

Currant Ribes L.

Currant, sticky Ribes viscosissimum Pursh

Dogwood Cornus L.

Dogwood, redosier Cornus sericea ssp. sericea L.

Douglas-fir Pseudotsuga menziesii (Mirb.) Franco

Elderberry Sambucus L.

Elderberry, blue Sambucus cerulea var. cerulea Raf.

Fir, grand Abies grandis (Dougl. ex D. Don) Lindl.

Fir, Pacific silver Abies amabilis Dougl. ex Forbes

Fir, subalpine Abies lasiocarpa (Hook.) Nutt.

Fir, white Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.

Goatweed Hypericum perforatum L.

Gooseberry Ribes L.

Hawthorn, black Crataegus douglasii Lindl.

Hawthorn, Columbia Crataegus columbiana Howell

Hawthorn, red Crataegus erythrocarpa Ashe

Hazel Corylus L.

Hazel, California Corylus cornuta var. californica (A. DC.) Sharp

1 According to Little (1979) and USDA-NRCS (1998).

65
Hemlock, western Tsuga heterophylla (Raf.) Sarg.

Horsechestnut Aesculus spp. L.

Juniper, common Juniperus communis L.

Juniper, Rocky Mountain Juniperus scopulorum Sarg.

Juniper, western Juniperus occidentalis Hook.

Kinnikinnick Arctostaphylos uva-ursi (L.) Spreng.

Locust Robinia L.

Larch, western Larix occidentalis Nutt.

Laurel Kalmia L.

Maple, Douglas Acer glabrum spp. douglasii (Hook.) Wesmael

Maple, Rocky Mountain Acer glabrum Torr.

Mockorange Philadelphus L.

Mockorange, Lewis Philadelphus lewisii Pursh

Mountain-ash, Sitka Sorbus sitchensis Roem.

Ninebark Physocarpus Maxim.

Ninebark, Pacific Physocarpus capitatus (Pursh) Kuntze

Oceanspray Holodiscus discolor (Pursh) Maxim.

Oregongrape Mahonia Nutt.

Peach Prunus L.

Pine, limber Pinus flexilis James

Pine, lodgepole Pinus contorta Dougl. ex Loud.

Pine, ponderosa Pinus ponderosa Dougl. ex Laws.

Pine, western white Pinus monticola Dougl. ex D. Don

Plum Prunus L.

Poisonivy, western Toxicodendron rydbergii (Small ex Rydb.) Greene

Pear Pyrus L.

Rose, wild Rosa L.

Serviceberry Amelanchier Medic.

Serviceberry, Saskatoon Amelanchier alnifolia var. humptulipensis (Jones) Hitchc.

Snowberry Symphoriocarpos Duham.

Snowberry, Columbia Symphoriocarpos albus var. laevigatus (Fern.) Blake

Spirea Spiraea L.

Spirea, shinyleaf Spriaea betulifolia ssp. lucida (Dougl. ex Greene) Hitchc.

Spruce, Engelmann Picea engelmannii Parry ex Engelm.

Sumac Rhus L.

Sumac, smooth Rhus glabra L.

Thimbleberry Rubus parvifolia Nutt.

Willow Salix L.

Yew, Pacific Taxus brevifolia Nutt.

66
This page has been left blank intentionally.

Document continues on next page.
Schoettle, Anna W.; Tonnessen, Kathy; Turk, John; Vimont, John; Amundson,

Robert, authors; Acheson, Ann; Peterson, Janice, tech. eds. 1999. An assessment the

effects of human-caused air pollution on resources within the interior Columbia River

basin. Gen. Tech. Rep. PNW-GTR-447. Portland, OR: U.S. Department of Agriculture,

Forest Service, Pacific Northwest Research Station. 66 p. (Quigley, Thomas M., ed.;

Interior Columbia Ecosystem Management Project: scientifice assessment).

An assessment of existing and potential impacts to vegetation, aquatics, and visibility within

the Columbia River basin due to air pollution was conducted as part of the Interior Columbia

Basin Ecosystem Management Project. This assessment examined the current situation and

potential trends due to pollutants such as ammonium, nitrogen oxides, sulfur oxides,

particulates, carbon, and ozone. Ecosystems and resources at risk are identified, including

certain forests, lichens, cryptogamic crusts, high-elevation lakes and streams, arid lands, and

class I areas. Current monitoring data are summarized and air pollution sources identified.

The assessment also includes a summary of data gaps and suggestions for future research

and monitoring related to air pollution and its effects on resources in the interior Columbia

River basin.

Keywords: Atmospheric deposition, acid rain, air pollution, aquatic effects, class I areas,

terrestrial effects, sensitive species, visibility.

The Forest Service of the U.S. Department of Agriculture is

dedicated to the principle of multiple use management of the

Nation’s forest resources for sustained yields of wood, water,

forage, wildlife, and recreation. Through forestry research,

cooperation with the States and private forest owners, and

management of the National Forests and National Grasslands, it

strives—as directed by Congress—to provide increasingly

greater service to a growing Nation.

The U.S. Department of Agriculture (USDA) prohibits

discrimination in all its programs and activities on the basis of

race, color, national origin, gender, religion, age, disability,

political beliefs, sexual orientation, or marital or family status.

(Not all prohibited bases apply to all programs.) Persons with

disabilities who require alternative means for communication of

program information (Braille, large print, audiotape, etc.) should

contact USDA’s TARGET Center at (202) 720-2600 (voice and

TDD).

To file a complaint of discrimination, write USDA, Director,

Office of Civil Rights, Room 326-W, Whitten Building, 14th

and Independence Avenue, SW, Washington, DC 20250-9410 or

call (202) 720-5964 (voice and TDD). USDA is an equal

opportunity provider and employer.

Pacific Northwest Research Station

333 S.W. First Avenue

P.O. Box 3890

Portland, Oregon 97208-3890