APPENDIX X

AIR QUALITY
AFFECTED ENVIRONMENT
AND
ENVIRONMENTAL CONSEQUENCES

California's sunny, mediterranean climate and the mountain ranges that form distinctive backdrops to the cities have made California an attractive place to live, resulting in growth that has made it most populated state in the nation. Unfortunately these three factors -- climate, geography and population-growth are also the major reasons for the state's worst air pollution. The mountain ranges that encircle the cities combine with layers of warm air in the upper atmosphere( a process known as temperature inversion) to create stagnant air masses. Population growth adds many sources of pollution. Sunlight triggers chemical reaction that turn invisible emissions into the familiar haze (impaired visibility) commonly known as "smog" and which results in many different air quality problems.

There are four major processes that effect air pollution (SPAM 1998):

1. Radiative Transfer
2. Atmospheric Transport and Dispersion
3. Chemical reactions
4. Hydrodynamics.
Atmospheric transport is strong in summer, weak or absent in winter, severe in the southern reaches, and moderate north of Sacramento where mountain slopes are gentle (SNEP 96) . Ozone has been found to be adversally affecting the Ponderosa and Jefferey pine. Radiative transfer, atmospheric transport and dispersion, and chemical reactions play major roles for high concentrations of Ozone in the Sierra Nevadas. Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs), precursors to Ozone, are emitted by moblile sources and carried from the Bay area, Sacramento and the central valley to the western slopes of the Sierra Nevadas by wind. These precusors are carried by wind toward the mountains. During the transport process the precursors react to form Ozone in the presence of sunlight. Other aerosols (e.g. ammonia, nitrates, sulfates, pesticides, herbicides and fine particulates) are also carried upwind. These are deposited on the vegetation (dry deposition) or brought down by rain, clouds fog or mist (Hydrodynamics-sometimes called "wet deposition" or "acid rain" if the pollutants are mainly sulfates and nitrates) and impact the vegetation or the watershed.

These fine particulates impair the visibilty of Class I areas. Visibility impairment results from both the scattering and absorption of light by particles and gases in the air. Fine particles (less than 2.5 micron in diameter-- PM2.5) are especially efficient at scattering light. Fine elemental carbon particles (soot) and nitrogen dioxide gas are the typical absorbers of light . Scattering by "air" molecules (primarily oxygen and nitrogen with diameter less thn 0.0001 microns) causes the sky to appear blue and, in the absence of natural particlulates, sets the limit on the best possible visibility for a specific geographic region.

Polluted air coming from outside a forest can impact the forest flora or fauna or watershed. On the other hand forest activities can generate pollutants that can affect the forest or the area and communities outside the forest boundaries. To fully understand the affected environment it is important to know the regulatory framework. For this reason, the laws and regulations concerning air quality are described below first followed by existing air quality descriptions of the area.

Regulatory Framework and Meteorological Factors Related to Air Quality

Air quality is managed through a complex series of federal, state, and local laws and regulations. The Environmental Protection Agency (EPA) has the primary federal role of ensuring compliance with the requirements of the Clean Air Act. The EPA issues national air quality regulations, approves and oversees State Implementation Plans (SIPs), and conducts major enforcement actions. States and local Air Pollution Control Districts (APCDs) and Air Quality Management Districts (AQMDs)have the primary responsibility of carrying out the development and execution of State Implementation Plans (SIPs), which must provide for the attainment and maintenance of air quality standards.

The original Air Quality Act was passed in 1963. This act was followed by the Clean Air Act Amendments in 1970, 1977, and 1990. The Clean Air Act Amendments of 1970, Section 109, required the EPA to develop primary National Ambient Air Quality Standards to protect human health and secondary standards to protect welfare.

National Ambient Air Quality Standards (NAAQS)

To protect human health, the EPA established National Ambient Air Qualiy Standards (NAAQS) for the following six criteria pollutants:

Particulate Matter less than 10 microns in diameter (PM 10),

Sulfur dioxide (SO2),
Nitrogen dioxide (NO2),
Ozone (O3),
Carbon monoxide (CO), and
Lead (Pb).

The standards for these pollutants are shown in Table 1. If the standards are violated in an area, that area is designated as "nonattainment" for that pollutant, and the State must develop a plan for bringing that area back into "attainment."

Table .1. National and State Ambient Air Quality Standards
(units are micrograms per cubic meter of air--µgms/m3)

Primary standards
Pollutant
Averaging time
Federal
State
PM10 Annual 50 30
24 hours 150 50
NO2 Annual 100(0.053) None
1 hour None 470(0.25)
CO 8 hours 10,000(g) 10,000
1 hour 40,000(35) 20,000
SO2 Annual 80(0.03) None
24 hours 365(0.14) 105(0.04)
3 hours None None
1 hour None 655(0.25)
03 1 hour 235(0.12) 180(0.09)
Pb Calendar quarter 1.5 None
30-day average None 1.5

1 Annual standards are never to be exceeded. Other standards are not to be exceeded more than once a year.
2 Arithmetic mean.
3 Geometric mean.

New Revised Standards

In July 1997, the EPA revised the existing national air quality standards for Ozone and particulate matter, and adopted a new standard for fine particles. The scientific review process determined that the ``old'' standards did not adequately protect public health. For ozone, longer- term exposures can cause significant health effects, including asthma attacks, breathing and respiratory problems, loss of lung function, and possible long-term lung damage and lowered disease immunity. For particulate matter, exposures to smaller sized particles (PM 2.5) can cause premature deaths, increased respiratory symptoms and disease ( especially for children and individuals with asthma), decreased lung function, and other serious respiratory problems. The new standards for particulate matter and Ozone are as follows:

Particulate Matter (PM2.5 )

The standard for PM10 remains essentially unchanged, while a new standard for PM2.5 is set at an annual limit of 15 micrograms per cubic meter, with a 24-hour limit of 65 micrograms per cubic meter.

Ozone

For ozone, the final standard is updated from 0.12 parts per million of ozone measured over one hour to a standard of 0.08 parts per million measured over eight hours, with the average fourth highest concentration over a three-year period determining whether an area is out of compliance.

The EPA's new ozone standards provide significant health benefits, especially for children. The new standard will prevent approximately 1 million incidences per year of significant decreases in children's lung function that can limit a healthy child's activity or increase medical treatment for children.

Prevention of Significant Deterioration Program (PSD)

The Prevention of Significant Deterioration (PSD) program was established in 1978 as a result of a lawsuit alleging that the Clean Air Act Amendments of 1977 required that a program be established to prevent degradation of air quality of regions in attainment. The program requires permits for new air pollution sources above a certain size. The emission from these sources cannot cause deterioration of ambient air quality beyond certain increments (referred to as PSD increments ) . The PSD increments for NO2, SO2, and PM10 were established for three classes of attainment areas: Class I and Class II as shown in table 2).

Class I areas include international parks, national parks larger than 6,000 acres, National Wildernesses greater than 5,000 acres, and National Wildlife Refuges in existence on August 7, 1977, when the amendments were signed into law. The Class I areas located in the affected area are:

1. Thousand Lakes Wilderness
2. Caribou Wilderness and
3. Lassen national park
Because PSD permits for Class I areas must be obtained before a pollution source is constructed, modeling is used to determine whether a source will produce emissions within the appropriate increments. The permittee for Class I areas must demonstrate that the proposed polluting facility will:
(1) not violate national or state ambient air quality standards,
(2) use the best available control technology to limit emissions,
(3) not violate either Class I or Class II PSD increments for SO2, NO2, and PM10 , and
(4) not cause or contribute to adverse impacts on Air Quality Related Values in any Class I area.
Table 2 shows Class I and Class II increments for PM10, total particulate matter, SO2, and NO 2. The Pacific Southwest Region of the U.S. Forest Service issued a "Guideline for Evaluating Air Pollution impacts on Class I Wilderness Areas in California" (Peterson et al. 1992) for use by the permittee. An interagency group (US Forest Service, National Park Service and Fish and Wldlife), called FLAG, is developing a document that will be applicable nationwide for use by a permittee. The objective is that all federal agencies with Class I areas will use a consistent approach for permit analysis and recommendation.

Table .2. Prevention of Significant Deterioration increments (µgms/m3)
Pollutant  Measure interval  Class I  Class II 
PM10 Annual
24-Hour
 4
8
17
30
Total Particulates Annual
24-hour
5
10
19
37
SO2 Annual
24-Hour
3-Hour
2
5
25
20
91
512
NO2 Annual 2.5 not available

Class II and Class III areas are allowed respectively larger increments of deterioration. The Clean Air Act did not mandate Class III designations but allowed states the authority to petition for redesignation to Class III. No area of California has requested redesignation to Class III; therefore, all the remaining attainment areas in the affected forests are designated as Class II. States also have the authority to redesignate areas to Class I if they fit the established criteria.

Air Quality Related Values

The 1977 Clean Air Act amendments gave federal land managers an "afirmative responsibility" to protect the Air Quality Related Values (AQRVs) of Class I areas from adverse air pollution impacts. AQRVs, as defined by Congress, include "the fundamental purposes for which Class I areas have been established and preserved by the Congress and the responsible federal agency" (Senate Report 95-127, p. 36). AQRVs are also those features or properties of a Class I area that can be changed by air pollution. A detailed discussion of AQRVs and sensitive indicators of pollution established on National Forests in the Pacific Southwest Region can be found in Peterson et al. (1992).

In April 1997 FLAG ( Federal Land Managers' Air Quality Related Values Work Group) was formed to develop a national document. The main objective was "to achieve greater consistency in the procedures each agency uses in identifying and evaluating AQRVs". The main items are:

· Define sensitive AQRVs
· Identify the critical loads or levels and the criteria that defines adverse impacts
· Standardize the methods and procedures for conducting AQRV analysis.
FLAG efforts focus primarily on four areas:
1. Terrestrial effects of Ozone
2. Aquatic and terrestrial effects of wet and dry pollutant deposition
3. Visibility
4. Process and Policy issues
FLAG's action plan calls for a phased approach. Phase I discusses issues that can be resolved relatively quickly, without the collection of new data. Phase II of the FLAG effort will address the more complex issues and unresolved issues from Phase I that may require additional data collection. The Phase I document has been drafted and is being reviewed for fine tuning.

Table 3 gives examples of AQRVs, sensitive receptors of pollution, and factors potentially changed by air pollutants. Among the sensitive receptors of air pollution, lichens and ponderosa pine are moderately studied. One of the ozone injury studies to ponderosa pine (Project Forest) plots is located in Lassen National Park.

Visibility as an AQRV

Visibility is an AQRV that is protected for all Class I areas. Congress established as a National goal "the prevention of any future and remedying of any existing impairment of visibility in mandatory Class I Federal areas where impairment results from man made air pollution."

Visibility conditions are affected by scattering and absorption of light by particles and gases. The fine particles most responsible for visibility impairment are sulfates, nitrates, organic compounds, soot, and soil dust. Fine particles are more efficient per unit mass than coarse particles at scattering light. Light scattering efficiencies also go up as humidity rises, due to water absorption on fine particles, which allows the particles to grow to sizes comparable to the wavelength of light. There are distinct regional variations in visibility between eastern and western states, due to generally higher relative humidities in the East. Naturally occurring visual ranges in the East may be between 105 to 190 kilometers, while natural visual ranges in the West are between 190 to 270 kilometers.

Visibility is an important public welfare consideration because of its significance to enjoyment of daily activities in all parts of the country. Visibility may be thought of as the atmosphere's tran11sparency to visible light (National Researcch Council 1993) and may be expressed in terms of :

· Visual Range - or the greatest distance at which a large black object can be distinguished against the horizon.
· Light Extinction -or the fraction of light attenuated by scattering or absorption over a given unit of the atmosphere (Visibility decreases as light extinction increases)
· Haziness Index - which is expressed in deciview (dv). The dv index increases from zero (representing pristine conditions) as visibility degrades.



The Information below does not show up in the printed version of the FEIS.  It stops at the above paragraph and then goes on to the Addition that was added to the table of contents (addition to Appendix X (MOU).  I will leave this information here until we find out if it is errata or needs to be removed.

Table 3. Examples of AQRVs, Sensitive Receptors, and Factors Potentially Changed by Air Pollution.

Air Quality Factors changed
Related Value Sensitive receptors by air pollution
Flora Ponderosa pine, lichens Growth, death, reproduction
visible injury
Water Alpine lakes Total alkalinity, pH, metal
concentration, dissolved oxygen
Soil Alpine soils pH, cation exchange capaicty,
base saturation
Visibility High usage vista Contrast, visual range, coloration
Cultural/
archaelogical values
Pictographs Decomposition
rate
Odor Popular hiking trail Ozone odor

Source: PSW GTR-136.

IMPROVE Network

Because most visibility degradation is from fine particulate matter, the EPA initiated continuous size-selective monitoring and elemental analysis of particles in 1977. This was replaced by the Interagency Monitoring of Protected Visual Environmental (IMPROVE) program. The National Park Service started the IMPROVE program as a coopertative effort with three other federal land management agencies (U.S. Forest Service, U.S. Fish and Wildlife Service, and Bureau of Land Management) and the EPA to monitor visibility at selected Class I areas. Data analysis in these areas is conducted by the University of California, Davis. Figure 2 shows IMPROVE sites within the Affected area.

The sampling and analytical protocols of IMPROVE are designed to meet the needs of the visibility studies. They must thus perform two functions that are quite independent: (1) determine fine particulate mass and all its major constituents, which, together, degrade visibility, and (2) determine element tracers to aid in establishihng the sources of the particles, natural and human-made, that degrade visibility. Hence, the purpose of the IMPROVE program is to provide a baseline of aerosol data to help identify possible sources of pollution. The standard protocol is to collect 24-hour samples, twice a week (Wednesday and Saturday). All major fine aerosol components and PM10 mass are measured, including several redundant measurements for quality assurance.

Existing requirements to consider effects on visibility which are reasonably attributable to a single nearby source or small number of sources are contained in the regulations published by EPA in 1980 at 40 CFR 51.300 (Protection of Visibility). Additional regulations (Regional Haze) are currently being finalized to address impairment of visibility that is more regional in its character and origins.

Regional Haze Program

The Preliminary Haze Program was released by the EPA on July 18, 1997 for public review. The final rules were released on April 22, 1999. Regional Haze is a revision to 1980 visibility regulations protecting class I areas.

Regional Haze rules sets the framework for each state. It sets criteria for measuring reasonable progress and provides flexibility for implementation. At present visibility impairment rules apply to the states with class I areas. The new rules apply to the states which `` may reasonably be anticipated to cause or contribute to any impairment of visibility'' in any class I area. Therefore interstate pollutants transport is fully addressed. Regional Progress Targets are established under the rules. Targets seek to improve the worst visibility days and maintain the best visibility days by implementing the following:

1. For the worst 20% of days, states will show one deciview improvement only 10 to 15 years
2. For the best 20% of days, states will not allow any degradation
Alternative targets for class I areas can be established in consultation with FLMs and EPA

The present IMPROVE network will be expanded to accomodate the new haze rules. The rule requires states, in consultation with federal land managers, to determine additional sites needed such that the monitoring network is ``representative'' of all Class I areas. If targets are not being achieved, each state contributing to impairment at the Class I area must check emission reductions achieved through its SIP. The state may coordinate with other pollutant contributing states for development of new measures.

Under the new rules the states are supposed to issue a visibility SIP. Each Class I area or its representative will be monitored from 2000 to 2004. The IMPROVE site at Lassen National park will represent Caribou and Thousand Lakes Class I areas. This will provide the baseline data for visibility. By the year 2060 the state will be required to achieve the visibility level to its natural background (which the state must presently identify).

INTERIM AIR QUALITY POLICY ON WILDLAND AND PRESCRIBED FIRES

The EPA on April 23, 1998 issued an Interim Air Quality Policy on Wildland and Prescribed Fires. The policy stresses collaboration of owners/managers of public, private and Indian wildlands with state/tribal air quality managers/air regulators to achieve their goals of :

1. allowing fire to function in its natural role in the wildlands
2. protecting public health and welfare
Ambient air quality worse than the NAAQS for PM10 and PM2.5 is used as the principal indicators of public health impact. Visibility impairment is used as the principal indicator of public welfare impact.

This is an interim policy for two reasons:

1. The EPA is expecting recommendations on how to treat air quality impacts from agricultural burning from the USDA's Air Quality Air Task Force.
2. The EPA will soon formulate the Regional Haze Rule. The impact of wildland and prescribed fires on regional haze can only be finalized then.
In the Interim Air Quality Policy on Wildland and Prescribed Fires, the EPA urges states and tribal air quality managers to collaborate with wildland owners and managers to mitigate the air quality impacts that could be caused by the increase of fire managed to achieve resource benefits. The EPA especially urges them to develop and implement at least basic Smoke Management Programs (SMP's) when conditions indicate that such fires will adversely impact the public. SMP's establish procedures and requirements for minimizing emissions and managing smoke dispersion. The goals of SMP's are:
1. to miligate the nuisance and public safety hazard (e.g. on roadways and airports, posed by smoke intrusions into populated areas)
2. to prevent deterioration of air quality and NAAQS violations
3. to address visibility impacts in mandatory class I federal areas
In exchange for states and tribes proactively implementing SMP's, the EPA intends to exercise its discretion not to redesignate an area as non attainment if the evidence is convincing that fires managed for resource benefits caused or significantly contributed to violations of the daily or annual PM10 or PM2.5 standards. The EPA, instead, will urge the state or tribe to review the adequacy of the SMP in collaboration with wildland owners/managers and make appropriate improvements to mitigate future air quality impacts. The SMP's are typically developed by states/tribes with cooperation and participation by wildland owners/managers. The SMP does not have to be incorporated into the SIP or be federally enforceable. The following are the basic components of a certifiable SMP.
A. Authorization to burn
B. Minimizing Air Pollutant Emissions
C. Smoke Management Components of Burn Plans
D. Public Education and Awareness
E. Surveillance and Enforcement
F. Program Evaluation
Reasonably Available Control Measures/Best Availale Control Measures

Section 190 of the Clean Air Act required the EPA to issue technical guidance on Reasonably Available Control Measures (RACMs) and Best Available Control Measures ( BACMs) for prescribed silvicultural and agricultural burning. RACMs or BACMs can be used as mitigation measures. Some examples of mitigation measures are:

1. annual burn plans,
2. emissions inventory systems,
3. daily burn planning/authorization and administration programs,
4.smoke dispersion evaluation processes etc,
Hazardous Air Pollutants

The 1990 amendments to the Clean Air Act include a list of 189 pollutants identfied as hazardous to human health. These pollutants are known to, or have the potential to, cause cancer, mutations, be toxic to nervous tissue, or cause reproductive dysfunction. Some of these air pollutants are emitted during forest fires, but they are not emitted in significant amounts and are not considered at this level of planning. Atmospheric transport of pesticides from California's Central Valley to the Sierra Nevada forests has been verified. The impacts of these pesticides to water quality and aquatic or terrestrial systems is not fully understood.

State Implementation Plans

Section 110 of the Clean Air Act requires states to develop State Implementation Plans (SIPs) that identify how the state will attain and maintain National Ambient Air Quality Standards and other federal air quality regulations. For all nonattainment areas, the state must demonstrate when and how these areas will be able to maintain National Ambient Air Quality Standards. How these areas will attain the standards is often based on the state's controls on new or existing air pollution sources. Controls can include more stringent pollution control requirements for industry, tighter requirements on wood-burning stoves or prescribed burning, or more stringent controls on mobile sources of emissions. States also have the authority to include air quality standards and regulations more stringent than federal standards and regulations. The Forest Service is required to comply with all of the requirements of a SIP.

California Clean Air Act

The California Clean Air Act of 1988 is administered by the California Air Resources Board. It added several requirements concerning plans and control measures to attain and maintain the State ambient air quality standards. One such requirement is for the board to establish designation criteria and to designate areas of the state as attainment, nonattainment, or unclassified for any state standards. Table 1 shows the state and national standards for six criteria pollutants. California has also established ambient air quality standards for sulfate, hydrogen sulfide, vinyl chloride, and visibility-reducing particles.

States have direct responsibility for meeting requirements of the Federal Clean Air Act and corresponding Federal regulations. As authorized by Division 26 of the California Health and Safety Code, California (i.e., the California Air Resources Board) is directly responsible for regulating emissions from mobile sources. However, authority to regulate stationary sources has been delegated to Air Pollution Control and Air Quality Management Districts (APCD or AQMD) at the county and regional levels. The state still has oversight authority to monitor the performance of district programs and can even assume authority to monitor the performance of district programs. It can even assume authority to conduct district functions if the district fails to meet certain responsibilities.

Many air pollution control and air quality management districts have not received delegation from the federal government for the Prevention of Significant Deterioration (PSD) Program. In California, districts that have received delegation and, therefore, have regulatory control are the Bay Area Air Quality Management District, Mendocino County Air Pollution Control District, Monterey Bay Unified Air Pollution Control District, North Coast Unified Air Quality Management District, Northern Sonoma County Air Pollution Control District, Sacramento County Air Pollution Control District, San Diego County Air Pollution Control District, Santa Barbara County Air Pollution Control District, and Shasta County Air Pollution Control District. Where districts have not been delegated, the PSD program is administered by the U.S. Environmental Protection Agency.

Title 17 Revision

The CARB issued Title 17 draft guidelines for updating California's prescribed burning regulations on August 10, 1998 with the following two objectives:

1. To accomodate large increases in prescribed burning without unacceptable increases in air quality.
2. To define a workable management plan for California's smoke management by working with all affected parties- local air districts, land management agencies, private industry and the public.
Some of the important points that will affect the prescribed burning program on the forests are:
1. Annual Registration for Prescribed Burns
2. Burn Plans to contain pertinent information
3. Burn Requests and Authorization
4. Smoke Dispersion Evaluation
5. Burn Accomplishment - Record Keeping
6. Wildland Fires Plans; Authorization; Monitoring and Interagency Consultation
7. Emission Reduction Techniques e.g. BMPs
8. Monitoring
9. Burner Qualification
10. Public Awareness Program
11. Surveillance and Enforcement
12. Oversight
13. Forms; Electronic copies; Information Transfers
An attempt will be made to incorporate the provisions requested in the EPA's Interim Air Quality Policy on Wildland and Prescribed Fires in the revised guidelines. The public hearing are being conducted from March to May. The final draft is planned to be published by the end of 1999.

Nevada Smoke Management Plan

The state of Nevada issued on August 21,1998 a similar draft to Title 17 in California. The comments are being solicited. The purpose of this plan is to coordinate and facilitate the statewide regulation of prescribed outdoor burning on lands in the state of Nevada. This plan is designed to meet the requirements of NRS445B.100 through 445B.845, inclusive which deals with air pollution, and the requirements of the EPA Interim Air Quality Policy on Wildland and Prescribed Fires.

· The major goals identified in the plan are:
· Protect human health and safety from the effects of outdoor burning
· Facilitate the enjoyment of the natural attractions of the state
· Keep the resident of the state informed
· Provide the opportunity for essential forest and range land burning while minimizing emissions
· Foster and encourage the development of reasonable alternative methods for disposing of or reducing the amount of organic refuse on lands in Nevada
· Acknowledge the role of fire in Nevada and allow the use of fire under controlled conditions to maintain healthy ecosystems while meeting the requirements of the Clean Air Act
Public comments are being solicited. The final plan will be ready by the end of the year.

North East Air and Smoke Alliance

The agencies (USFS, NPS, BLM, CDF ) and the private timber companies involved in the use of prescribed fire, in the counties of Lassen, Plumas, Sierra, Modoc, Tehama and Yuba and the respective APCDs have formed an alliance. The purpose is to achieve the prescribed fire objectives and maintain levels of air quality which will protect human health and welfare. The group meets quarterly and share the pertinent information about the burns and develop strategies to resolve air and smoke issues.

PRESCRIBED FIRE INCIDENT REPORTING SYSTEMS (PFIRS)

The Interagency Air and Smoke Council (IASC) has cooperatively developed a Prescribed Fire Incident Reporting System that will track prescribed fires in the state. The burn agency will enter all the pertinent information about the burn project. The local regulatory agency will be able to access the burn information and issue ``go'' ``no go'' authorization. The server is located at Mather, Aviation Office of US Forest Service. The system will be operational by the end of 1999.

The Sierra Nevada Conservation Framework EIS will discuss other air issue like ozone injury, nitrogen deposition, acid deposition, pesticide transport and deposition. Only the particulate emission originating from wildland fires and their impacts are discussed here. The new revised PM2.5 standards, updated Title 17 and Nevada Smoke Plan would put additional pressure on mountain counties and urban communities to control winter wood burning smoke. Continued monitoring , data tracking will provide opportunity for reduction of emission through other alternative application like biomass, mechanical and chemical treatment.

Meteorological Factors Related to Air Quality

Weather patterns strongly influence air quality and smoke management by controlling the dispersion of emissions from fires. The primary weather conditions that affect dispersion are atmospheric stability, mixing height, and transport wind speed. Atmospheric stability refers to the tendency for air to mix vertically through the atmosphere. Mixing height is the vertical distance through which air is able to mix. The transport wind speed is a measure of the ability to carry emissions away from a source horizontally. These three factors determine the ability of the atmosphere to disperse and dilute emissions that are released from prescribed fires and wildfires.

The physical shape of landscapes interacts with and controls some weather patterns that influence emission dispersion. On a local or regional basis, the air flow in California is channeled by mountain ranges. The predominant wind direction in a valley is parallel to the valley's longitudinal axis in one direction, and the second most prevalent wind direction is in the opposite direction.

The coastal mountain ranges limit the accessible routes for marine air to move to the interior of California, and accessible routes are limited to breaks or low points in the coastal range. The principal break occurs in the San Francisco Bay Area (Carquinez Straits), and the greatest part of the marine air reaching the Central alley of California traverses this area (California Air Resources Board, Aerometric Data Division, February 1994).

During the winter, wind occasionally originates from the south and flows in a north-northwesterly direction. The valleys experience light, variable winds of less than 10 miles per hour. Low wind speeds, combined with low inversion layers in the winter, create a climate conductive to high PM10 concentrations.

During the summer, winds usually originate in the north and flow in a south-southeasterly direction.

It is not uncommon for wind speeds and directions to change throughout the day. During the day, north-northwesterly winds prevail. However, in the late evening through early morning hours, wind flow is affected by cooler drainage winds from the surrounding mountains, and wind direction changes to a south-southwesterly flow.

The major large scale meterological feature occuring in spring is movement of the Pacific High to the north, which shifts the tracks of storms; precipitation therefore declines. However spring weather is rarely warm and dry. Significant precipitation continues and temperatures remain cool throughout the spring. A common occurrence during the spring months is the incursion of cold unstable air from the North Pacific causing brief periods of intense rain and often accompanied by thunderstorms. During summer climate becomes dry and temperature increases. The fall is typically a transition period between dry summer and wet winter conditions. Generally weather conditions are dominated by clear cool days with temperature at night falling to almost below freezing.

Weather systems are generally accompanied by good dispersion conditions (i.e. strong winds and unstable air mass). During fair weather periods the atmosphere stabilizes and wind speeds are reduced. The terrain induced features (i.e. valleys, canyons) could produce local stagnation and trapping of pollutants.

Prescribed burning is conducted when transport winds are not expected to carry emissions to designated areas in quantities that affect prevention of Significant Deterioration increments and visibility. State law requires the regulation of prescribed burns. Prescribed burning activities are coordinated with the states and local air quality agencies to ensure that atmospheric stability and mixing heights are advantageous for dispersion of emissions. The state board declares a Permissive Burn Day when expected weather conditions will provide enough ventilation to disperse the smoke pollutants. Daily agricultural burning control decisions are issued for fourteen air basins.

Table 4 shows the air basins and air pollution control districts associated with each Affected Forest and each affected county. The three air basins in the analysis area are the Northest Plateau, Sacramento Valley and Mountain Counties. All local air pollution control districts are responsible for controlling acreages and placement of prescribed burns in their districts.

Table .4. Affected counties and air basins by National Forest
Forest SO-City County County Seat Air Basin Air Pollution
Control District
Lassen Susanville Lassen
Tehama
Butte
Shasta
Plumas
Susanville
Red Bluff
Oroville
Redding
Quincy
Northeast Plateau
Sacramento Valley
Sacramento Valley
Sacramento Valley
Mountain Counties
Lassen County
Tehama County
Butte County
Shasta County*
Northern Sierra*
Plumas Quincy Plumas
Butte
Yuba
Quincy
Oroville
Marysville
Mountain Counties Sacramento Valley
Sacramento Valley
Northern Sierra*
ButteCounty
Feathern River*
Tahoe Nevada City Yuba
Sierra
Nevada
Placer
Marysville
Sierraville
Nevada City
Auburn
Sacramento Valley
Mountain Counties
Mountain Counties
Sacramento Valley/
Lake Tahoe
Feather River*
Northern Sierra*
Northern Sierra*

Placer County

Air quality in the analysis area

State and federal agencies have established ambient air quality standards for various pollutants. If the permissible levels of a particular pollutant are not exceeded in an area, the area is said to be in "attainment" for that pollutant; if the standards are violated, the area is designated as "non-attainment.". Table 5 shows the designation for the area counties.

Table 5. Area Designation for State and Federal Standards for PM10 and Ozone
County PM10 Ozone
Federal State Federal State
Butte A N A U
Lassen A N A A
Nevada A N A N
Plumas A N A U
Shasta A N A N
Sierra A N A U
Tehama A N A T
Yuba A N A N
A----Attainment
N----Non-attainment
T-----transitional
U----Unclassified

Table below gives existing emissionsof Total Organic Gases (TOG), Reactive Organic Gases ( ROG), Carbon Monoxide (CO), Nitrogen Oxides (NO), Sulfur Oxides (SO) and Particulates smaller than ten microns (PM10)

Table 6. Population, Area, and Emissions by County (1996)
(Tons/day)
County  Popn Area TOG ROG CO NO SO PM 10
Butte 196,500 670 32 26 150 20 0.8 29
Lassen 32,650 4560 15 12 86 9.9 0.7 24
Nevada 87,100 975 20 14 110 10 0.6 18
Plumas 20,250 2569 20 16 140 7.5 0.5 20
Shasta 161,700 3793 37 28 250 31 1.8 32
Sierra ?,370 958 5.4 4.6 38 2.1 0.4 11
Tehama 54,400 2980 15 10 88 17 0.9 18
Yuba 60,500 640 11 9.2 58 8.5 0.5 15
Adapted from CARB 1998 ``Emission Inventory 1996''

Emissions from Fires in the Affected Forests

Forest activities that generate air pollutants include timber sales, road construction, site preparation, mining, and prescribed burns. Although activities other than prescribed burns and wildfires can contribute significant amounts of air pollutants at a local level, at the scale of analysis in this EIS, the contribution of these other activities to air pollution is insignificant.

Prescribed burning is a diverse, dynamic source of air pollution, representing hundreds of individual fires annually in California. Individual fires vary in size from a few acres to several thousand acres. The affected forests vary greatly in the number of acres burned, the type of material or vegetation burned, and when that burning occurs. No two situations are exactly alike in terms of the factors that control the mass of pollutants emitted during prescribed burning.

Table 7 PM10 Emissions from prescribed burns by Area Counties from 1993 to 1998 (tons)
County/Forest 1993 1994 1995 1996 1997 1998 Total
Lassen NF
Lassen 351 72 285 492 760 579 2539
Shasta 138 105 153 50 0 159 605
Plumas 86 10 45 139 60 107 447
Tehama 19 17 14 53 49 8 160
Butte 11 17 0 7 1 3 39
Total 605 221 497 741 870 856 3790
Plumas NF
Lassen
Plumas 280 249 191 278 216 205 1419
Butte 68 55 34 48 68 68 341
Total 348 304 225 326 284 273 1760
Sierraville
Sierra 124 150 62 97 114 78 625
Total 124 150 62 97 114 78 625

Prescribed fires followed pretreated acres. The fuel loading amounted to 10 tons per acre (personal communication with the forest). Percent combustion was assumed to be sixty. For wildfire acres, it was assumed that fire went through untreated acres. Fuel loading was assumed to be 35 tons per acre and eighty percent of the fuel was consumed.

Table 8 PM10 emissions from Wildfires by Area Counties from1993 to 1998 (tons)
County/Forest 1993 1994 1995 1996 1997 1998 Total
Lassen NF
Lassen 1 2 2 40 0 45
Shasta 1 2 1 11 46 1 62
Plumas 1 3 4 2 7 1 18
Butte 0
Tehama 9764 9764
Total 3 9771 5 15 93 2 9891
Plumas NF
Lassen 1 637 0 1 1 1 641
Plumas 88 14 11 2077 13 2 2205
Butte 55 13 1 5 2 4 80
Total 144 664 12 2083 16 7 2926
Sierraville
Sierra 1 13768 - 3 2 1 13775
Plumas 0 1 0 183 3 1 188
Total 1 13769 0 186 5 2 13963

Prescribed burning on the affected forests was analyzed for 1993 through 1998. Trends in the use of prescribed fire for this period were representative of recent forest management practices, and data quality was reasonably good during this period. Information regarding fuel consumed (in tons) by burning was more difficult to obtain, therefore estimates were made based on average fuel consumption data from the literature and expert opinion. The emission tables given in the R-5 Conformity Handbook (approved by EPA Region IX) were utilized to calculate PM 10.

Prescribed burning during the 1980s was generally used to dispose of debris left over from timber harvests (usually called ``slash burning'') and to reduce moisture stress and growing-space competition on trees from other vegetation. Slash burning was used to reduce wildfire hazard and to prepare harvested sites for planting. After the 1990s the acres requiring prescribed fire for slash burning and site preparation decreased due to decreased timber harvest.

The impact of prescribed burning on air quality from 1993 to 1998 is difficult to quantify. The burning of logging debris can create large quantities of particulate matter and other pollutants. This burning usually takes place, however, in relatively remote areas with intensities that vent smoke high into the atmosphere, where it is widely dispersed.

PM10 emissions from wildfire on the Primary Forests from 1993-1998 are shown in table 8 by each county. The wildfires emit high amount of emissions per acre as compared to prescribed fires.

Visibility in Class I Areas

Visibility conditions in the Sierra Nevadas improve from south to north and also from low elevation to high elevations. Visibility conditions at Lassen Volcanic national park, the most northerly and highest Class I area in the Sierra Nevadas are among the cleanest measured nation wide, while Sequioa National Park , one of the southernmost and lowest , experiences some of the worst visibility conditions for a western U.S. Class I area.

Lassen National park is the site for the IMPROVE network and will represent Caribou and Thousand Lake Class I areas. The major aerosols contributing to visibility impairment are sulfate, nitrate, organic, elemntal carbon and particulates. Table 9 shows the aerosol concentration.

Table 9 Measured fine and coarse aerosol concentration in ugms/m3
Season Fine Mass Sulfate Nitrate Organic Elemental carbon Soil Coarse Mass
Spring 3.1 0.7 0.3 1.4 0.2 0.7 3.7
Summer 3.8 0.8 0.2 2.1 0.3 0.6 4.1
Autumn 3.3 0.6 0.2 1.8 0.2 0.4 3.0
Winter 1.9 0.3 0.2 1.0 0.3 0.1 1.8
Annual 3.1 0.6 0.2 1.6 0.2 0.5 3.0

Table 10 Measured fine aerosol mass budgets in percent
Season Sulfate Nitrate Organic Elemental  Soil
Spring 20.7 8.0 43.8 5.5 21.9
Summer 19.7 4.1 54.8 6.6 14.8
Autumn 18.4 6.8 54.2 6.9 13.7
Winter 16.5 9.1 53.6 13.1 7.7
Annual 19.1 6.5 51.7 7.4 15.2

Table 11 Seasonal and annual averages of reconstructed aerosol light extinction coefficient (Mm -1) for the Lassen park IMPROVE network. Also shown are the light extinction coefffiecients (Mm -1) resulting from sulfate, nitrate, organic carbon, light absorption, and coarse particles/fine soil.
Season Aerosol
Extinction
Sulfate Nitrate Organics Absorption Soil and Coarse
Spring 22.9 7.1 2.7 5.5 4.6 2.9
Summer 27.6 8.0 1.7 8.4 6.4 3.0
Autumn 21.0 4.7 1.6 7.1 5.2 2.3
Winter 14.2 3.6 1.8 4.1 3.5 1.2
ANNUAL  21.6 5.9 1.9 6.4 5.0 2.4
Data From Improve report 1996

Table 12 Seasonal and annual averages of percentage contributions to the reconstructed aerosol light extinction coeffiecient (light extinction budget) for the Lassen Park IMPROVE network for sulfate, nitrate, organic carbon, absorption, and coarse particle/fine soil.
Season Sulfate Nitrate Organics Absorption Soil and Coarse
Spring 31.2 11.7 24.1 20.3 12.8
Summer  29.1 6.2 30.5 23.4 10.9
Autumn 22.6 7.8 33.8 25.0 10.7
Winter 25.5 12.7 28.9 24.4 8.4
ANNUAL 27.3 9.0 29.4 23.2 11.1

The data analyzed in the IMPROVE report is an average of data from Crater lake and Lassen Park. Both sites are very similar. The report names this region as "Humboldt Mountain Ranges". . For this region, total reconstructed light extinction averaged 31.6 Mm -1 with maximum extinction in summer (37.6 Mm -1 ) and minimum extinction in winter (23.2 Mm -1). The seasonality is primarily variations from sulfate and organic extinctions and absorption. Organic carbon, sulfate, and elemental carbon contribute almost equally to annual extinction at 29.4%, 27.3% and 23.2%, respectively.

The best visibility in the West occurs during the winter with a minimum deciview (dv) of 7 being reported at Bridger Wilderness followed by 8 dv at Jarbridge and Lassen. The region of 10 or less dv's encompasses a broad expanse that covers the Sierra-Humboldt, Sierra Nevada, Great Basin, Central Rockies, and the northwestern half of the Colorado Plateau.

Fine aerosols are the most effective in scattered light and are the major contributors to light extinction. In most cases, the sulfate component of fine aerosol is the largest single contributor to light extinction. This is because sulfate, being hygroscopic, generally has a higher light extinction efficiency than other species due to associated liquid water. This is especially true in the eastern United States. Organics are the major source for the Class I areas.

Environmental Consequences

Estimates of the expected annual acreage of prescribed fire, wildfire, and mechanical removal of fuels were calculated for the Affected Counties for each of the alternatives. Assumptions regarding the ecological need for prescribed burning, the hazard reduction that might be necessary for site preparation were made at a programmatic level. These estimates are very generalized because many assumptions for each alternative within each county can be validated only with watershed and landscape-level analysis.

A description of the dominant forest vegetation type was assumed based on field experience of forest personnel for each of the prescribed and wildfires from 1993 to 1998. Forest area descriptions were used to assign preburn fuel loadings based on standardized values available from the natural photo series. Fuel loadings were estimated for areas where natural fuels dominated and where activity-generated fuels dominated. Activity generated fuels may originate from timber harvest or thinning activities, and they may be left in place or concentrated into piles before burning. Fuel loading was estimated in two categories, woody fuels and litter/duff, and then totaled. Finally one average value was assumed for calculations based on the field experience. Separate tables were developed for prescribed fire and wildfire displaying fuel loading, percent combustion, and emission factor by vegetation type during write up of California Spotted Owl EIS. These tables, also given in the Air Quality Conformity Handbook, 1995 ( Tables 7 and 8 and approved by the EPA), were utilized to calculate PM 10 emissions. Emission levels for PM10 were calculated for wildfire and prescribed fires separately and are displayed in the affected environment section..

The amount and type of prescribed burning projected under each alternative represent a shift in emphasis compared to historical uses of prescribed fire. In the eighties, the majority of prescribed burning has consisted of broadcast burning of logging slash for site preparation and management of competing vegetation. Now, a pretreatment thinning or biomass removal or a mechanical treatment will be done. Much of this burning would be underburning, in which a low- to moderate-intensity fire burns under a stand of residual trees. Burning for hazard reduction and site preparation may frequently take place in stands with many more trees retained than previously left after harvest, necessitaing changes in prescribed fire techniques. Burning piles of slash after harvest, or for hazard reduction, will be done during the most favorable emission dispersion conditions.

For emissions, the shift in emphasis to underburning has some inherent risks along with its advantages. Large areas may burn in mosaics with varying fire intensity and severity. Although this mimics natural underburning, there are risks associated with retaining coarse woody debris. The likelihood for reburning is increased, as is the possibility for a prescribed burn to escape the planned burn area. Consequently the potential for additional, unanticipated emissions is also increased. Furthermore, costs associated with the need for rapid extinguishment of smoldering fuels may also become higher. Thus, fire management planning and risk assessment would need to become more fully integrated into land management planning decisions as part of ecosystem management.

Where extensive fuel hazard reduction by prescribed burning is considered, a tradeoff analysis is necessary to compare emission levels from both wildfire and prescribed fire. It is expected that prescribed burning under advantageous weather conditions may reduce subsequent wildfire emissions by decreasing the amount of available fuel and lowering the risk of large-scale wildfire. A tradeoff analysis would document this reduction and the possible associated changes in air quality impacts.

The forests are also looking at opportunities to reduce fuel loading through biomass and mechanical removal or treatment, which would result in a net reduction in emissions to the atmosphere. There are some problems associated with these opportunities, however. Biomass removal requires proximity to cogeneration facilities, and mechanical removal depends upon factors such as terrain, soil type, and surface rockiness.

Fugitive dust will be produced during road construction. Mitigations measures such as watering roads to control dust would make cumulative impacts insignificant.

Emissions by alternative

Emissions of PM10 were calculated based on projections of the number of acres to be burned under each alternative. Tables 1 - 3 shows PM10 and PM2.5 emitted under each alternative by county and type of prescribed burning.

Table 1
PM10/PM2.5 Emissions From Prescribed Burns
(Hand Pile)
County Acres PM10 PM2.5
ALTERNATIVE 1
BUTTE
329
10.2
8.7
LASSEN
4710
146.0
124.1
NEVADA
185
5.7
4.9
PLUMAS
2088
64.7
55.0
SHASTA
1214
37.6
32.0
SIERRA
555
17.2
14.6
TEHAMA
281
8.7
7.4
YUBA
281
8.7
7.4
ALTERNATIVE 2
BUTTE
1862
57.7
49.1
LASSEN
5818
180.4
153.3
NEVADA
233
7.2
6.1
PLUMAS
11868
367.9
312.7
SHASTA
1862
57.7
49.1
SIERRA
698
21.6
18.4
TEHAMA
465
14.4
12.3
YUBA
465
14.4
12.3
ALTERNATIVE 3
BUTTE
1899
58.9
50.0
LASSEN
5935
184.0
156.4
NEVADA
237
7.3
6.2
PLUMAS
12107
375.3
319.0
SHASTA
1899
58.9
50.0
SIERRA
712
22.1
18.8
TEHAMA
475
14.7
12.5
YUBA
475
14.7
12.5
ALTERNATIVE 4
BUTTE
1198
37.1
31.6
LASSEN
3744
116.1
98.7
NEVADA
150
4.7
4.0
PLUMAS
7637
236.7
201.2
SHASTA
1198
37.1
31.6
SIERRA
449
13.9
11.8
TEHAMA
300
9.3
7.9
YUBA
300
9.3
7.9
ALTERNATIVE 5
BUTTE
1275
39.5
33.6
LASSEN
3984
123.5
105.0
NEVADA
159
4.9
4.2
PLUMAS
8128
252.0
214.2
SHASTA
1275
39.5
33.6
SIERRA
478
14.8
12.6
TEHAMA
319
9.9
8.4
YUBA
319
9.9
8.4

Table 2
PM10/PM2.5 Emissions From Prescribed Burns
(Machine Pile)
County Acres PM10 PM2.5
ALTERNATIVE 1
BUTTE
329
24.4
20.7
LASSEN
4710
349.1
296.7
NEVADA
185
13.7
11.7
PLUMAS
2088
154.8
131.5
SHASTA
1214
90.0
76.5
SIERRA
555
41.1
35.0
TEHAMA
281
20.8
17.7
YUBA
281
20.8
17.7
ALTERNATIVE 2
BUTTE
1862
138.0
117.3
LASSEN
5818
431.2
366.5
NEVADA
233
17.3
14.7
PLUMAS
11868
879.7
747.7
SHASTA
1862
138.0
117.3
SIERRA
698
51.7
44.0
TEHAMA
465
34.5
29.3
YUBA
465
34.5
29.3
ALTERNATIVE 3
0.0
BUTTE
1899
140.8
119.6
LASSEN
5935
439.9
373.9
NEVADA
237
17.6
14.9
PLUMAS
12107
897.4
762.8
SHASTA
1899
140.8
119.6
SIERRA
712
52.8
44.9
TEHAMA
475
35.2
29.9
YUBA
475
35.2
29.9
ALTERNATIVE 4
BUTTE
1198
88.8
75.5
LASSEN
3744
277.5
235.9
NEVADA
150
11.1
9.5
PLUMAS
7637
566.1
481.1
SHASTA
1198
88.8
75.5
SIERRA
449
33.3
28.3
TEHAMA
300
22.2
18.9
YUBA
300
22.2
18.9
ALTERNATIVE 5
BUTTE
1275
94.5
80.3
LASSEN
3984
295.3
251.0
NEVADA
159
11.8
10.0
PLUMAS
8128
602.4
512.1
SHASTA
1275
94.5
80.3
SIERRA
478
35.4
30.1
TEHAMA
319
23.6
20.1
YUBA
319
23.6
20.1

Table 3
PM10/PM2.5 Emissions From Prescribed Burns
(Underburn)
County Acres PM10 PM2.5
ALTERNATIVE 1
BUTTE
2635
179.4
152.5
LASSEN
37684
2566.3
2181.3
NEVADA
1479
100.7
85.6
PLUMAS
16704
1137.5
966.9
SHASTA
9704
660.8
561.7
SIERRA
4436
302.1
256.8
TEHAMA
2251
153.3
130.3
YUBA
2251
153.3
130.3
ALTERNATIVE 2
BUTTE
14893
1014.2
862.1
LASSEN
46542
3169.5
2694.1
NEVADA
1862
126.8
107.8
PLUMAS
94947
6465.9
5496.0
SHASTA
14893
1014.2
862.1
SIERRA
5586
380.4
323.3
TEHAMA
3724
253.6
215.6
YUBA
3724
253.6
215.6
ALTERNATIVE 3
BUTTE
15192
1034.6
879.4
LASSEN
47477
3233.2
2748.2
NEVADA
1900
129.4
110.0
PLUMAS
96854
6595.8
5606.4
SHASTA
15192
1034.6
879.4
SIERRA
5697
388.0
329.8
TEHAMA
3798
258.6
219.8
YUBA
3798
258.6
219.8
ALTERNATIVE 4
BUTTE
9584
652.7
554.8
LASSEN
29950
2039.6
1733.7
NEVADA
1198
81.6
69.3
PLUMAS
61099
4160.8
3536.7
SHASTA
9584
652.7
554.8
SIERRA
3595
244.8
208.1
TEHAMA
2395
163.1
138.6
YUBA
2395
163.1
138.6
ALTERNATIVE 5
BUTTE
10200
694.6
590.4
LASSEN
31876
2170.8
1845.1
NEVADA
1276
86.9
73.9
PLUMAS
65026
4428.3
3764.0
SHASTA
10200
694.6
590.4
SIERRA
3826
260.6
221.5
TEHAMA
2550
173.7
147.6
YUBA
2550
173.7
147.6

Table 4 shows the emissions saved through biomass and sawlog removal, and mechanical removal of fuels. The latter may be termed savings (equivalent of offsets).

Table 4. Tons of Emissions (tons) Saved Annually Under Each Alternative
Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5
Sawlog and Biomass Removal 412,000 1,064,000 1,138,400 514,400 104,000
PM10 Saved 5,150 13,300 14,230 6,430 1,300
PM2.5 Saved 4,378 11,305 12,096 5,466 1,105

Levels of PM10 between 1981 and 1990 provide a useful comparative baseline for assessing projected emissions under the various alternatives for the Primary Forests . This data was calculated during the California Spotted EIS write up and is shown in Table 5.

Table 5. Annual PM10 Wildfire Emissions in Tons by Primary Forests from 1981 to 1990
Forest 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
Lassen 0 0 0 214 266 0 3650 423 60 1911
Plumas 2578 4 4 92 7 35 7893 129 2683 875
Tahoe 0 0 0 6 15 445 3434 145 36 14

Altenatives 2 and 3 would generate the greatest PM10/PM 2.5 emissions in the first five years (Tables 1 - 3).Alternative 1 and 4 would generate the least PM10/ PM2.5 emissions. Maximum emissions are generated in Plumas county in all alternatives except alternative 1 where maximum emissions are in Lassen county.

Under Alternative 2, 3 and 5 emissions are projected to increase above historic levels in Lassen and Plumas Counties. These increases are largely due to increases in prescribed burning under the Alternatives.

Table-6 Historical level of PM10 and PM2.5 under Prescribed and Wildfire

(tons/year)
Wildfire Prescribed
Forest PM10 PM2.5 PM10 PM2.5
Lassen 653 522 210 168
Plumas 1430 1144 1418 1134
Tahoe 409 327 157 126
data from revised DEIS for CA spotted owl 1996 PM2.5 were assumed to be 80% of PM10

In the forests for which historic data are available ( Lassen, Plumas, Tahoe, ) emissions are projected to increase under all alternatives relative to the historic level. Emissions would be highest in these forests under Alternative 2, 3 and 5. Alternative 1 would generate the lowest projected emission of 6267 tons per year.

The projected overall increase in estimated emissions makes it reasonable to conclude, at this scale, that the proposed actions may degrade air quality. Nonetheless, aggregated emissions could mask regional or basin-level conditions that may result in localized adverse impacts.

The characterisitcs and quantification of emissions (e.g., plume direction and pollutant concentration) from prescribed fire are critical when evaluating impacts on human health and the environment. The analyses need to include the application of available air dispersion models in order to understand and estimate the downwind impacts on air quality from prescribed fire. Models currently available, such as NFSPUFF, SASEM, and CALPUFF, vary in scope and function, and none has been extensively field tested to verify accuracy in predicting downwind pollution concentrations. NFSPUFF has been modified to be applicable to Region 5 of the USFS. NFSPUFF includes an emission production module (EPM) with National Weather Service predictions for upper level winds, and an alogrithm to correct these winds fo terrain effects at lower levels. It

combines these pieces to produce a graphic display of predicted smoke trajectories and concentrations. NFSPUFF can handle many fires on the same day, each with separate emission characteristics and ignition times. Wind predictions are downloaded through a modem from the National Weather Service nested grid model; the resulting local data file is parsed automatically by NFSPUFF. Terrain effects are computed with a user's option of 1,2,4,and 8 kilometer resolution in the western US between 30 and 50 degrees north latitude and 100 to 125 degrees west longitude.

We used NFSPUFF model to predict the downward smoke dispersion and PM10 concentrations by simulating a worst case scenario. We assumed four test burns from alternative 2 with maximum acreage for burning, within twenty miles of Susanville, being ignited the same day. The burn date was assumed to be May 5, 1999. The weather conditions were assumed to be what existed on May 5, 1997 and model was run assuming May 5, 1997 as May 5, 1999. The test site locations were selected based on historical burns around those vacinities. The following tables lists the assumed burn unit characteristics:

Table 7 Assumed Burn Unit Characteristics
PARAMETER TEST SITE 1 TEST SITE 2 TEST SITE 3 TEST SITE 4
Latitude 40.266 40.433 40.477 40.212
Longitude 120.591 120.490 121.172 121.350
Acreage 510 510 510 510
Slope 25% 25% 25% 25%
Snowmelt Month April April April April
Harvest date April, 1996 April, 1996 April 1996 April 1996

The following table gives the fuel loading characteristics. It is assumed that all the prescribed burn sites had a preburn treatment. Two types of vegetation was assumed --Ponderosa pine and Mixed conifers. Ten tons of fuel loadings with the following characteristics were assumed. The fuel loading is low because the projected burns will follow the pretreated acres.

Table 8 Assumed fuel loadings for NFSPUFF
PARAMETER VALUE (tons/acre)
Ponderosa pine Mixed Conifer
Fuel Loading by Size Class:
1 -hour (0-1/4 inches) 0.5 1.0
10 -hour (1/4-1 inches) 0.5 1.0
100 -hour (1-3 inches) 1.0 1.0
1000 -hour (3-9 inches) 2.0 1.5
10000 -hour (9-20 inches) 3.0 2.5
100000+ -hour (20+ inches) 3.0 3.0
Duff depth 0.1 inch 0.5 inch

The assumed understory burn scenario is given in the following table :

Table 9 Understory Burn Scenario used in NFSPUFF modeling
PARAMETER Testsite1 Testsite2 Testsite3 Testsite4
Burn date 5/5/1999 5/5/1999 5/5/1999 5/5/1999
Ignition Start Time 10:30 11:15 12:30 13:40
Ignition Duration 300 min 300 min 300 min 300 min
Number of Ignition Periods 1 1 1 1
10-Hr Fuel Moisture 10% 10% 10% 10%
1000-Hr Fuel Moisture 32% 32% 32% 32%
Fuel Moisture Method Adjusted Adjusted Adjusted Adjusted
Days Since Rainfall 7 7 7 7
Surface Windspeed 2 mph 2 mph 2 mph 2 mph

The burn was assumed to have taken place on May 5, 1999 but metrological conditions were assumed as that what existed on May 5, 1997. It is also assumed that it is a state declared burn day. This means that the background level is average or below the standards for the area for those days. The modeling analysis shows that under similar conditions the concentations of PM10 and PM2.5 will stay below standards. Figures that display smoke dispersion and PM10 average (24 hour) concentrations are available for public review in the project file.

At this programmatic, broad scale of analysis, the alternatives would not create conditions that are likely to violate state or federal standards. However, additional air quality analysis would need to be done at the project level with exact metrological and field conditions.

Emissions of smoke during prescribed burning may reduce visibility in some locations, but implementation of smoke dispersion practices, mitigation measures, and best available control measures can minimize the visibility impairment. Smoke emissions may also cause adverse health effects on sensitive individuals, including asthmatics, children and the elderly, especially in the vicinity of the fire.

Unpleasant odors and reduced visibility may be detected by wilderness visitors and could effect the recreational experience for those trying to seek solitude and escape signs of human activity.

The PM10 emissions from prescribed burning would contribute to PM10 loading locally, regionally, and globally. The local effects include cumulative prescribed burn emissions from within federal, state, and private lands in the area. Currently, PM10 atmospheric concentrations do not exceed national standards. However, the Affected Forests generally exceed the more restrictive California State Standards. Additional PM10 emissions from prescribed burning could increase the existing problem. PM10 or PM 2.5 emissions from household wood burning and fugitive dust from soil-disturbing activities within or outside the area could aggravate the problem. These impacts should be analyzed at the project level.

Regulatory authorities are primarily concerned with public exposure to PM10/PM2.5 concentrations measured in 24-hour increments. Emissions from prescribed burning projects will be managed for dispersion and separation over time and space to minimize the potential for violation of standards.

Carbon dioxide emitted by burning of wood can contribute to the global ``green house effect.'' The effect of pescribed burning on the greenhouse effect is probably negligible but its cumulative impact is unknown.

Emission Savings

The projected emissions are low due to disposition of fuels through alternative methods - that is , biomass or mechanical removal or treatment to reduce fuel loading (see Table 4). Cogeneration plants can burn this wood with substantially lower emissions than would result from wildfire or prescribed burning. Various types of mechanical treatment can be used to clear away brush and trees to prepare land for planting, and to break up slach into finer material. Mechanical mowers and shredders can be used to clear away brush and trees for tree planting in open areas. Bulldozers or tractors used to clear land could be used to reduce fuel loading. However, this kind of clearing has the potential for soil compaction.

Improved utilization of timber is an attractive alternative to prescribed burning that the forests are employing. This encompasses the use of material, which is normally burned, as well as improved harvesting techniques that generate less slash material. Examples of improved harvesting methods that are being used include the following:

· Directional felling to reduce log breakage
· Prelogging or postlogging activities to recover small-diameter timber
· Better techniques for handling material normally discarded as slash.
· Design of contractual agreements to encourage recovery of small-diameter material.

No burn treatment is another method of preventing emissions on a short term basis. The elimination of any form of prscribed burning causes no immediate adverse side effects on the environment, but it does not accomplish any of the benefits for which prescribed fires are used. Moreover, no treatment for extended periods of time can increase the risk of losses due to wildfire or insect infestation and can diminish species diversity and site productivity. A no-burn strategy cannot be considered a viable option for saving emissions.

The ability to reduce emissions by altering the firing technique is limited because firing techniques are dictated by the type of fuel and the objectives of the prescribed burning. Field and laboratory tests have indicated that various firing techniques are asssociated with various levels of emissions. For example, back fires emit relatively little particulate matter.

Fugitive dust is expected under each alternatives that require road construction. The dust will be kept to minimum through dust abatement procedures (e.g. watering). The cumulative impact to particulate concentrations will be insignificant but will be analysed at the project level.

MITIGATION, MONITORING, AND THE NEED FOR ADDITIONAL ANALYSIS

Mitigation

Various techniques can be used to reduce the amount of smoke produced from a prescribed burn. The techniques used would depend upon whether there is an overstory of trees and whether there are activity-generated fuels or natural fuels. The techniques can be categorized according to factors that determine the amount of emissions generated, such as the number of acres burned, preburn fuel loadings, fuel consumption, and weather.

Number of acres burned --- Perhaps the most obvious method to reduce emissions is to consider each project area and determine whether prescribed burning is the most effective option for treatment. In some cases, alternative silvicultural stand management methods, mechanical removal, or other methods may be viable alternatives for meeting management objectives, eliminating the need to burn.

Density management through thinning and understory removal would improve stand conditions in some cases and may alleviate the need for burning. Silvicultural activities could concentrate on the development of late-successional forest characteristics and increasing resiliency to large-scale disturbances by fire, wind, insects, and disease.

Manual treatment consists of hand piling and may not include burning fuels. This method is generally used for specific silvicultural and hazard reduction objectives. Manual treatment is labor intensive and is thus associated with high costs. It is not usually cost effective in areas of heavy fuel loadings or large areas.

Mechanical treatments rearrange and change size and shape of the slash (fuels) components. Mastication (mowing or shredding) crushes and shreds small-diameter concentrations of slash into a scattered layer of residue on the ground. This level of treament is generally sufficient for silvivultural objectives but may not significantly reduce wildfire hazard. Equipment is limited to slopes less than 30 percent. Application in areas with heavy fuel loadings may not be feasible, and mechanical treatments in natural stands may conflict with other resource management objectives.

Chipping on-site may be used to treat slash. Chipping can range from labor-intensive to highly mechanized operations. Residue can be spread on site or hauled away depending on local chip market conditions. Residue can be piled with various types of machinery. Piling could be used for all levels of fuel concentrations depending on the type of equipment. Terrain and soil conditions are the limiting factors. Although some grappler machines are made for slopes in excess of 20 percent, cost may become a critical issue.

Preburn fuels loading --- If prescribed fire is determined to be the optimal treatment for an area, reducing the preburn fuel loading will reduce the subsequent emissions. Methods to reduce fuel loading include whole-tree removal, firewood sales, and increased utilization . Because of new technology, there are more opportunities for increased utilization of residue. For example, some lumber mills are able to use hole wood down to a 4-inch diameter. However, this may conflict with guidelines for retention of coarse woody debris.

Fuels consumption -- Burning under conditions that reduce the portion of biomass that is consumed would lower the emissions produced. The objective should be to burn only the biomass that needs to be burned. This could be accomplished by burning woody fuel when duff moisture contents are high, increasing the rate of mop-up, isolating large fuels and stumps from burning, burning only fuel concentrations, burning when moisture is high in large fuels, or using high-intensity firing techniques.

Favorable weather conditions --- Managing smoke emissions may include transporting smoke away from sensitive areas and diluting emissions by projecting the smoke plume into transport winds. Burning during the spring affords the greatest opportunity to mitigate to prescribed fire smoke impacts because atmospheric instability and persistent transport winds are common. Fuel moisture is optimal for emission reduction during early spring. Fall and winter temperature inversions often restrict pollutants to ground level when burning takes place under the inversion layer. Winter burning of piles, if conducted at high elevations, may not affect smoke-sensitive areas because burning is done above the inversion layer.

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