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Agricultural Burning

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Prescribed fire has long been a useful management tool for croplands, rangelands, and forests.  As concern for air quality increases, however, it becomes more important to ensure that intentional or prescribed burning is used responsibly. EPA is working with the agricultural community to devise reasonable, science-based policies that define the role of agricultural burning in a way that allows efficient agricultural production as well as a healthy environment.

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Related publications from the Ag Center
Agricultural Burning

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National Homeland Security Research Center - The National Homeland Security Research Center (NHSRC) develops and delivers reliable, responsive expertise and products based on scientific research and evaluations of technology. Our expertise and products are widely used to prevent, prepare for, and recover from public health and environmental emergencies arising from terrorist threats and incidents.

More information from USDA
CSREES National Air Quality Program
USDA Forest Service: BlueSky Framework - A Web-Based Information System to Help Manage Prescribed Burning, Wildland Fires and Agricultural Burning

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Center for Ag Air Quality Engineering and Science

Background: Clean Air Act -- Title I

Pursuant to Title I of the CAA, EPA has established national ambient air quality standards (NAAQSs) to limit levels of "criteria pollutants," including carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone, and sulfur dioxide.

EPA calls these pollutants "criteria air pollutants" because the agency has regulated them by first developing health-based criteria (science-based guidelines) as the basis for setting permissible levels. One set of limits (primary standard) protects health; another set of limits (secondary standard) is intended to prevent environmental and property damage.

A geographic area that meets or does better than the primary standard is called an attainment area; areas that don't meet the primary standard are called nonattainment areas. A single geographic area may have acceptable levels of one criteria air pollutant but unacceptable levels of one or more other criteria air pollutants; thus, an area can be both attainment and nonattainment at the same time.

Under Section 110 of the CAA, each state must develop a State Implementation Plan (SIP) to identify sources of air pollution and to determine what reductions are required to meet federal air quality standards. A State Implementation Plan is a detailed description of the programs a state will use to carry out its responsibilities under the Clean Air Act.

Technical guidance and data sources
EPA maintains a Clearinghouse for Inventories and Emission Factors (CHIEF). The CHIEF web site provides access to tools for estimating emissions of air pollutants in various geographic domains (e.g. urban areas, regions, or the entire nation). It serves as EPA's central clearinghouse for the latest information on air emission inventories and emission factors. Emission estimation data bases, newsletters, announcements, and guidance on performing inventories are included in CHIEF.

The Factor Information Retrieval (FIRE) Data System (one of the tools offered by CHIEF) is a database management system containing EPA's recommended emission estimation factors for criteria and hazardous air pollutants. FIRE includes information about industries and their emitting processes, the chemicals emitted, and the emission factors themselves. The FIRE database is designed for use by local, state, and federal agencies, environmental consultants, and others who require emission factor information for estimating both criteria and toxic air emissions from stationary sources.

More information from EPA
Compilation of Air Pollutant Emission Factors -- AP-42, Fifth Edition, Volume I
EIIP Preferred and Alternative Methods for Estimating Air Emissions (PDF) (72 pp, 252K) -- Volume III, Chapter 16 - Open Burning
EIIP Preferred and Alternative Methods for Estimating Air Emissions -- Volume VIII, Chapter 11 -- Methods for estimating greenhouse gas emissions from burning of agricultural crop wastes (currently under revision)

The 1990 Clean Air Act gives important enforcement powers to EPA. It used to be very difficult for EPA to penalize a company for violating the Clean Air Act.  The 1990 law enables EPA to fine violators. Other parts of the 1990 law increase penalties for violating the Act and bring the Clean Air Act's enforcement powers in line with other environmental laws.

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Clean Air Act

More information from EPA
Text of the Clean Air Act
Clean Air Act -- Plain English Guide
State Air Programs
Clean Air Act (CAA) Enforcement Policy and Guidance

Telephone assistance from EPA
EPA's Control Technology Center (919-541-0800) provides general assistance and information on CAA standards.

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Air Emissions From Agricultural Practices

Under Section 110 of the CAA, each state must develop a State Implementation Plan (SIP) to identify the sources of air pollution and to determine what reductions are required to meet federal air quality standards.

State implementation plans are collections of the regulations used by a state to reduce air pollution. The Clean Air Act requires that EPA approve each state implementation plan. Members of the public are given opportunities to participate in review and approval of state implementation plans.

The degree to which ambient air emissions from farming practices -- such as prescribed burning -- are allowed are location-specific (specific to a geographic area) within each State Implementation Plan. Visibility standards may also apply through the State Implementation Plan. Locations that are in areas that have been classified as "nonattainment areas" under the National Ambient Air Quality Standards are subject to more restrictions.

The U.S. Department of Agriculture (USDA) has established the Agriculture Air Quality Task Force. Exit EPA EPA is an active participant in the Task Force. The Task Force has unanimously endorsed a listing of high priority research needs to improve the level of understanding of the impact of agriculture on air quality levels.

On February 25, 1998, the USDA and EPA announced a Memorandum of Understanding (MOU) to ensure that the two agencies work together to provide a healthy environment with clean air in harmony with a strong agriculturally productive nation. The MOU establishes a framework for the two agencies to share expertise and a process for involving the agricultural community in a cooperative effort to address agriculture-related air quality issues, including emissions from agricultural burning.

EPA will work with the task force to refine the distinction between wildland fires (which are covered by EPA's Interim Air Quality Policy on Wildland and Prescribed Fires) and agricultural burning.

Related environmental requirements 
CAA Section 109 - 110
40 CFR Part 52 Exit EPA - contains approval and promulgation of each state's specific implementation plan (SIP)

Related information

More information from EPA
National Ambient Air Quality Standards
Nonattainment Areas for Criteria Pollutants
Classifications of Particulate Matter Nonattainment Areas

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Prescribed Burning

Prescribed burning is a land treatment, used under controlled conditions, to accomplish natural resource management objectives. It is one of several land treatments, used individually or in combination, including chemical and mechanical methods.

Prescribed fires are conducted within the limits of a fire plan and prescription that describes both the acceptable range of weather, moisture, fuel, and fire behavior parameters, and the ignition method to achieve the desired effects. Prescribed fire is a cost-effective and ecologically sound tool for forest, range, and wetland management. Its use reduces the potential for destructive wildfires and thus maintains long-term air quality. Also, the practice removes logging residues, controls insects and disease, improves wildlife habitat and forage production, increases water yield, maintains natural succession of plant communities, and reduces the need for pesticides and herbicides.

The major air pollutant of concern is the smoke produced. Smoke from prescribed fires is a complex mixture of carbon, tars, liquids, and different gases. This open combustion source produces particles of widely ranging size, depending to some extent on the rate of energy release of the fire. The major pollutants from wildland burning are particulate, carbon monoxide, and volatile organics. Nitrogen oxides are emitted at rates of from 1 to 4 g/kg burned, depending on combustion temperatures. Emissions of sulfur oxides are negligible.

Some pollution prevention practices that can be used during prescribed burning operations include the following:

Related publications from the Ag Center
Ag Sector Profiles (Sector Notebooks)

More information from EPA
Compilation of Air Pollutant Emission Factors: Wildfires and Prescribed Burning (Chapter 13.1) (PDF) (14 pp, 76K)
Interim EPA Air Quality Policy on Wildland and Prescribed Fires

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Particulate matter is the term for solid or liquid particles found in the air. Some particles are large or dark enough to be seen, such as soot or smoke. Others are so small they can be detected only with an electron microscope.

Breathing particulate matter can cause serious health problems. Particulates also reduce visibility in many parts of the United States. They can also accelerate corrosion of metals and damage paints and building materials such as concrete and limestone.

Sources of particulates
"Coarse" particles are larger than 2.5 micrometers and generally come from sources such as vehicles traveling on unpaved roads, materials handling, crushing and grinding operations such as cement manufacturing, and combustion sources.

Particles less than 2.5 micrometers (0.0004 inch) in diameter are known as "fine" particles. Fine particles result from fuel combustion in motor vehicles, power plants and industrial facilities, residential fireplaces, woodstoves, wildfires, and prescribed forest burning. Fine particles can also be formed when combustion gases are chemically transformed into particles.

Health effects of particulates
Particulate matter less than 10 micrometers in size, including fine particles less than 2.5 micrometers, can penetrate deep into the lungs. On a smoggy day, one can inhale millions of particles in a single breath. Tens of millions of Americans live in areas that exceed the national health standards for particulates.

In recent studies, exposure to particulate pollution -- either alone or with other air pollutants -- has been linked with premature death, difficult breathing, aggravated asthma, increased hospital admissions and emergency room visits, and increased respiratory symptoms in children. People most at risk from exposure to fine particulate matter are children, the elderly, and people with chronic respiratory problems.

Environmental effects of particulates
Fine particles scatter and absorb light, creating a haze that limits our ability to see distant objects. Particle plumes of smoke, dust, and/or colored gases that are released to the air can generally be traced to local sources such as industrial facilities or agricultural burning. Regional haze is produced by many widely dispersed sources, reducing visibility over large areas that may include several states.

The Clean Air Act established special goals for visibility in some national parks and wilderness areas. In 1994, EPA began developing a regional haze program that is intended to ensure that continued progress is made toward the national visibility goal of "no manmade impairment." Such control efforts would likely result in improved public health protection and visibility in areas outside national parks as well.

More information from EPA
Information on Particulate Matter
Grand Canyon Visibility Transport Commission Recommendations (PDF) (109 pp, 1.5MB) Exit EPA
Grand Canyon Visibility -- Draft Regulatory Language (PDF) (8 pp, 21K)
Annex to the Report of the Grand Canyon Visibility Transport Commission (PDF) (162 pp, 329K)

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State Programs and Information Exit EPA

More information from the states Exit EPA
Air Pollution State Resource Locator - State and regional regulatory agencies and rules covering topics such as open burning, smoke and dust

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Federal Government Information

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Federal, Regional, and State Contacts

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