HomeMy WebLinkAboutChapter 15 - Air QualityChapter 15: Air Quality
Final Draft August 8, 2005
Butte County General Plan Background Report
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CHAPTER 15: AIR QUALITY
TABLE OF CONTENTS
15.1 INTRODUCTION...............................................................................................................................................3
THE AIR POLLUTION PROBLEM .................................................................................................................................3
THE ENVIRONMENTAL REVIEW PROCESS ..................................................................................................................4
DISTRICT’S ROLE IN CEQA.......................................................................................................................................4
Lead Agency.........................................................................................................................................................4
Responsible Agency..............................................................................................................................................4
Commenting Agency ............................................................................................................................................4
RELATIONSHIP TO NATIONAL ENVIRONMENTAL POLICY ACT (NEPA).....................................................................4
LEAD AGENCY CONSULTATION .................................................................................................................................5
15.2 LAND USE AND AIR QUALITY LINKAGE..................................................................................................5
BCAQMD PERMIT REQUIREMENTS ..........................................................................................................................5
LAND USE CONFLICTS AND EXPOSURE OF SENSITIVE RECEPTORS ............................................................................6
LAND USE AND DESIGN CONSIDERATIONS ................................................................................................................7
15.3 TOPOGRAPHY AND CLIMATE.....................................................................................................................8
INTRODUCTION ..........................................................................................................................................................8
WIND SPEED AND DIRECTION ..................................................................................................................................10
TEMPERATURE.........................................................................................................................................................10
TEMPERATURE INVERSIONS .....................................................................................................................................11
PRECIPITATION AND FOG .........................................................................................................................................12
15.4 AIR QUALITY REGULATION......................................................................................................................13
INTRODUCTION ........................................................................................................................................................13
FEDERAL .................................................................................................................................................................13
STATE ......................................................................................................................................................................16
REGIONAL ...............................................................................................................................................................18
THE BCAQMD’S ROLE...........................................................................................................................................19
AIR QUALITY PLANS ...............................................................................................................................................19
BCAQMD RULES, REGULATIONS, AND PROGRAMS ...............................................................................................20
TOXIC AIR POLLUTANTS .........................................................................................................................................20
PUBLIC EDUCATION PROGRAM ................................................................................................................................21
AGRICULTURAL OPEN BURNING..............................................................................................................................21
RESIDENTIAL/DOORYARD OPEN BURNING ..............................................................................................................22
15.5 AIR QUALITY IN BUTTE COUNTY AND THE SACRAMENTO VALLEY AIR BASIN DISTRICTS
.....................................................................................................................................................................................23
POLLUTANT .............................................................................................................................................................23
STATE ......................................................................................................................................................................23
AIR POLLUTANT PROPERTIES, HEALTH EFFECTS AND SOURCES .............................................................................24
POLLUTANT: OZONE ................................................................................................................................................24
POLLUTANT: REACTIVE ORGANIC GASES (ROG)....................................................................................................25
POLLUTANT: NITROGEN OXIDES (NOX)..................................................................................................................26
POLLUTANT: CARBON MONOXIDE (CO)..................................................................................................................26
POLLUTANT: PARTICULATE MATTER (PM-10 AND PM-2.5)...................................................................................28
SPECIFIC ANNUAL AIR QUALITY DATA ...................................................................................................................29
Introduction........................................................................................................................................................29
Air Quality Data Tables – Explanatory Notes ...................................................................................................29
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LIST OF TABLES
TABLE 15-1 EXAMPLES OF PROJECTS REQUIRING BCAQMD AIR QUALITY PERMITS...................................................6
TABLE 15-2 NATIONAL AND CALIFORNIA AMBIENT AIR QUALITY STANDARDS..........................................................15
TABLE 15-3 AIR QUALITY MONITORING DATA IN THE NORTHERN SVAB (ACTIVE AS NOTED BELOW).......................18
TABLE 15-4 BUTTE COUNTY AMBIENT AIR QUALITY ATTAINMENT STATUS ..............................................................23
TABLE 15-5 BUTTE COUNTY 2001 ROG EMISSIONS....................................................................................................25
TABLE 15-6 BUTTE COUNTY 2001 NOX EMISSIONS ....................................................................................................26
TABLE 15-7 BUTTE COUNTY 2001 CO EMISSIONS ......................................................................................................28
TABLE 15-8 BUTTE COUNTY 2001 PM-10 EMISSIONS .................................................................................................29
TABLE 15.9A OZONE TRENDS SUMMARY: BUTTE COUNTY - CHICO-MANZANITA AVENUE ........................................30
TABLE 15.9B OZONE TRENDS SUMMARY: BUTTE COUNTY – PARADISE AIRPORT .......................................................30
TABLE 15.10A PM10 TRENDS SUMMARY: BUTTE COUNTY-CHICO-MANZANITA AVENUE..........................................30
TABLE 15.10B PM10 TRENDS SUMMARY: BUTTE COUNTY – PARADISE-FIRE STATION #1.........................................30
LIST OF FIGURES
FIGURE 15-1 AERIAL VIEW OF SACRAMENTO AND SAN JOAQUIN VALLEY ....................................................................9
FIGURE 15-2 TEMPERATURE INVERSION ......................................................................................................................12
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15.1 INTRODUCTION
Air quality in a region depends upon the direct and indirect sources of air pollution in the area, as
well as wind and weather patterns that circulate or trap air from other regions. This chapter
describes the sources and impact of air pollution in Butte County, as well as the various
regulatory agencies that oversee air quality. The contents of the chapter are based upon the Air
Quality Element for General Plans Technical Support Document (AQTSD), an advisory
document published by the US. Environmental Protection Agency (EPA) that provides uniform
procedures for addressing air quality in environmental documents to lead agencies, consultants,
and project applicants. This document provides technical air quality information and
recommendations to control or reduce emissions associated with new and modified indirect
sources of air pollution. Indirect sources include employment sites, shopping centers, sports
facilities, housing developments, airports, places of business, and other human activities.
The Butte County Air Quality Management District (BCAQMD) has jurisdiction over most air
quality matters in Butte County. The BCAQMD is tasked with implementing certain programs
and regulations required by the Federal Clean Air Act (FCAA) and the California Clean Air Act
(CCAA). The BCAQMD prepares plans to attain state and federal ambient air quality standards.
In order to accomplish its mandates, the BCAQMD maintains a staff of technical personnel who
are versed in the various aspects of air pollution control and analysis.
The BCAQMD 1991 Air Quality Attainment Plan (AQAP) includes a control measure for an Air
Quality Element for General Plans. The program requires the BCAQMD to provide technical
assistance to lead agencies in addressing air quality issues in environmental documents and to
comment on project air quality impacts. In addition, the BCAQMD suggests mitigation measures
to reduce air quality impacts of development projects. Based on the request of Butte County, the
BCAQMD drafted this chapter.
The Air Pollution Problem
Butte County is classified as “moderately” nonattainment for ozone and particulate matter. The
air quality in Butte County is a reflection of the population growth of the region and the
surrounding counties and the fact that Butte County is a central place for urban demands
including medical, retail, government, education, employment, housing, and transportation. The
metropolitan area also draws customers from well beyond adjoining counties because of the
outdoor recreation attraction of the northern part of the state. It should also be noted that the
northern part of the valley is subject to significant ozone transport from the Broader Sacramento
Planning Area. These factors, coupled with the region’s climate and topography, have caused the
air quality of the area to become “moderately” polluted with ozone (smog) and particulates (dust
and smoke).
The “moderate” pollution standard is based on health criteria established by the California Clean
Air Act. If nothing is done to decrease pollution levels, the region may eventually be subject to
expensive and punitive mandates of the Federal Clean Air Act, including the denial of federal
grants and highway funds for transportation, transit, and sewerage projects.
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The Environmental Review Process
The California Legislature enacted CEQA in 1970 [Public Resources Code (PRC) §21000 et
seq.]. CEQA requires public agencies (i.e., local, county, regional, and state government) to
consider and disclose the environmental effects of their decisions to the public and governmental
decision-makers. Further, it mandates that agencies implement feasible mitigation measures or
alternatives that would mitigate significant adverse effects to the environment. Finally, CEQA
provides a mechanism for disclosing to the public the reasons why a governmental agency
approved a project that would have significant environment effects.
District’s Role In CEQA
As a public agency, the BCAQMD takes an active part in the intergovernmental review process
under CEQA. The BCAQMD may act as a lead agency, a responsible agency, or a commenting
agency.
Lead Agency
The BCAQMD acts as a lead agency when it has principal responsibility to carry out or approve
a project. This typically occurs when it develops rules, regulations, and air quality plans.
Responsible Agency
The BCAQMD acts as a responsible agency when it has discretionary power over a project but
does not have the principal authority to carry out the project. The BCAQMD is often a
responsible agency for development projects that require air pollution control permits. As a
responsible agency, the BCAQMD is available to help identify applicable District rules and
regulations, to provide guidance and assistance on applicable air quality analysis methodologies,
and to help address any other air quality related issues. The BCAQMD will also submit
comments to the lead agency through the intergovernmental review process on the adequacy of
the lead agency’s air quality analysis. As part of the review, the BCAQMD may recommend
mitigation measures to help reduce or eliminate impacts.
Commenting Agency
The BCAQMD acts as commenting agency for any project that has the potential to impact air
quality and for which it is not a lead or responsible agency.1 To this end, it regularly provides
comments to lead agencies that prepare environmental documents.
Relationship To National Environmental Policy Act (NEPA)
Some projects subject to CEQA may also require compliance with federal environmental law,
namely the National Environmental Policy Act (NEPA). The air quality analyses prepared in
1 CEQA Guidelines [CCR §15044] permits any person or entity that is not a responsible agency to comment to a
Lead Agency on any environmental impact of a project.
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accordance with this document should be adequate in most cases to meet NEPA as well as
CEQA requirements.
Lead Agency Consultation
The BCAQMD is available for consultation at any time in the project review process, but there
are certain times when consultation is required. For example, when the BCAQMD has
discretionary approval authority over a project, which another public agency is serving as lead
agency, the BCAQMD is to be consulted as a responsible agency. When the BCAQMD does not
have any approval authority over a project, it is to be consulted as a commenting agency. CEQA
requires or provides opportunities for consultation at various times during the environmental
review process.
Addressing land use and site design issues while a proposed project is still in the conceptual
stage increases opportunities to incorporate mitigation measures and desirable modifications to
minimize air quality impacts. Public agencies can use the initial consultation phase to address air
quality issues most effectively by becoming familiar with this guidance document and user-
friendly computer programs that perform screening-level air quality analyses, such as
URBEMIS, and by using the BCAQMD as a resource.
The latest URBEMIS 2002 model (version 7.5.0) estimates air pollution emissions from a wide
variety of land use projects and is available on the South Coast Air Quality Management
District’s Website at Transportation and Land Use Programs Computer Model (URBEMIS 2002
v.7.5.0).
15.2 LAND USE AND AIR QUALITY LINKAGE
The air quality considerations that warrant particular attention during early consultation between
Lead Agencies and project proponents include:
• Consistency with applicable BCAQMD rules, regulations and permit requirements;
• Land use conflicts and exposure of sensitive receptors to odors, toxics and air pollutants;
and
• Land use and design measures to encourage alternatives to the automobile and conserve
energy.
Lead agencies and project proponents are encouraged to consult with the BCAQMD on these
issues.
BCAQMD Permit Requirements
The BCAQMD permit requirements apply to most industrial processes (e.g., manufacturing
facilities, cement terminals, food processing), many activities (e.g., print shops, dry cleaners,
gasoline stations), and other miscellaneous activities (e.g., demolition of buildings containing
asbestos and aeration of contaminated soils). Table 15-1 shows a sample of activities subject to
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District permit requirements. During early consultation, lead agency staff should address air
pollution regulations and requirements of other public agencies that may apply to the proposed
project. Lead Agency staff is encouraged to coordinate directly with the BCAQMD during the
environmental review process on issues such as regulatory requirements, impact analyses and
mitigation measures. Copies of rules and regulations may be requested by writing, calling, or
emailing: BCAQMD at 2525 Dominic Drive, Suite J, Chico, CA 95928; (530) 891-2882;
www.bcaqmd.org.
TABLE 15-1
EXAMPLES OF PROJECTS REQUIRING BCAQMD AIR QUALITY PERMITS
The BCAQMD Rule 400 states that “any person building, erecting, altering or replacing any article, machine, equipment or other
contrivance, the use of which may cause the issuance of air contaminants, shall first obtain written authorization for such
construction from the Air Pollution Control Officer (APCO).”
Examples of air contaminant emitting equipment and processes include (but are not limited to):
Agricultural Products Processing (hullers, driers, dehydrators, etc.)
Bulk Material Handling
Chemical Blending, Mixing, Manufacturing, Storage, etc.
Metals Etching, Melting, Plating, Refining, etc.
Plastics & Fiberglass Forming and Manufacturing
Petroleum Production, Manufacturing, Storage, and Distribution
Rock & Mineral Mining and Processing
Solvent Use (Degreasing, Dry Cleaning, etc.)
Surface Coating and Preparation (Painting, Blasting, etc.)
Note: Equipment operated and installed without an Authority to Construct is subject to legal action and fines up to $25,000 for each day of
violation.
Land Use Conflicts and Exposure of Sensitive Receptors
The location of a development project is a major factor in determining whether it will result in
localized air quality impacts. Adverse air quality has a greater potential to harm people when the
source of emissions are closer to populations. Of particular concern are impacts on sensitive
receptors, which are facilities that house or attract children, the elderly, people with illnesses or
others who are especially sensitive to the effects of air pollutants. Hospitals, schools,
convalescent facilities, and residential areas are examples of sensitive receptors.
For each of the situations discussed below, the impacts generally are not limited only to sensitive
receptors. Air pollutants including toxic air contaminants, odor, and dust can adversely affect all
members of the population, and thus any consideration of potential air quality impacts should
include all members of the population. However, this discussion focuses on sensitive receptors,
because they are the people most vulnerable to the effects of air pollution.
Air quality problems arise when sources of air pollutants and sensitive receptors are located near
one another. There are several types of land use conflicts that should be avoided:
• A sensitive receptor is in close proximity to a congested intersection or roadway with
high levels of emissions from motor vehicles. High concentrations of carbon monoxide,
fine particulate matter or toxic air contaminants, such as diesel exhaust, are the most
common concerns.
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• A sensitive receptor is close to a source of toxic air contaminants or a potential source of
accidental releases of hazardous materials.
• A sensitive receptor is close to a source of odorous emissions. Although odors generally
do not pose a health risk, they can be quite unpleasant and often lead to citizen
complaints to the district and to local governments.
• A sensitive receptor is close to a source of high levels of nuisance dust emissions.
Localized impacts to sensitive receptors generally occur in one of two ways:
• A (new) source of air pollutants is proposed to be located close to existing sensitive
receptors. For example, an industrial facility is proposed for a site near a school.
• A (new) sensitive receptor is proposed near an existing source of air pollutants. For
example, a residential development is proposed near a wastewater treatment plant.
Early consultation between project proponents and lead agency staff can avoid or minimize
localized impacts to sensitive receptors. When evaluating whether a development proposal has
the potential to result in localized impacts, lead agency staff need to consider the nature of the air
pollutant emissions, the proximity between the emitting facility and sensitive receptors, the
direction of prevailing winds, and local topography. Often, the provision of an adequate distance,
or buffer zone, between the source of emissions and the receptor(s) is necessary to mitigate the
problem. This underscores the importance of addressing these potential land use conflicts during
the preparation of the general plan and as early as possible in the development reviews for
specific projects.
In some instances, some of the land use considerations discussed in the next section (e.g., infill
development and mixed use projects) could result in localized impacts to sensitive receptors. For
example, an infill or mixed-use project might result in residences being in close proximity to a
source of odors or toxic air contaminants, or a child care facility might be proposed at a worksite
in an area where large quantities of hazardous materials are stored and used. Such situations
should be avoided. Lead agencies should bear in mind that while infill and mixed-use
development are desirable (to reduce auto trips), such projects should be approved only when
they do not subject receptors to potential health or nuisance impacts.
Land Use and Design Considerations
Land use decisions are critical to air quality planning because land use patterns greatly influence
transportation needs, and motor vehicles are the largest source of air pollution. The location,
intensity and design of land use development projects significantly influences how people travel.
For example, land use strategies such as locating moderate or high-density development (more
than eight dwelling units per acre) near transit stations increases opportunities for
residents/employees to use transit rather than drive their cars. Similarly, design considerations
such as orienting a building entrance towards a sidewalk and/or transit stop increases the
attractiveness of walking and transit as an alternative to driving. Some important land use and
design issues to consider include the following:
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• Encourage the development of higher density housing and employment centers near
transit stations.
• Encourage compact development featuring a mix of uses that locates residences near jobs
and services.
• Provide neighborhood retail within or adjacent to large residential developments.
• Provide services, such as restaurants, banks, copy shops, and post offices, within office
parks and other large employment centers.
• Encourage infill development.
• Be sure that the design of streets, sidewalks and bike paths/routes within a development
encourages walking and biking.
• Orient building entrances towards sidewalks, and transit stops.
• Provide landscaping to reduce energy demand for cooling.
• Orient buildings to minimize energy required for heating and cooling.
Local governments and other lead agencies are encouraged to consider land use and design
measures to reduce automobile use and promote energy conservation early in planning and
development review processes. By incorporating such measures in local plans and addressing
them during initial contacts with project proponents, lead agencies greatly increase the likelihood
of their implementation. The environmental impacts of development proposals may be lessened
and environmental review processes simplified.
15.3 TOPOGRAPHY AND CLIMATE
Introduction
The California Air Resources Board (ARB) has divided California into regional air basins
according to topographic air drainage features. The valley opens to the sea at the Carquinez
Straits where the San Joaquin-Sacramento Delta empties into San Francisco Bay. The
Sacramento Valley, thus, could be considered a "bowl" open only to the south. Figure 15-1
provides a computer enhanced aerial view of the Sacramento and San Joaquin Valleys and
demonstrates the bowl created in both the northern and southern end of the entire valley. Due to
these unique topographic and localized meteorological conditions, ARB has designated the
Sacramento Valley as a separate air basin (referred to as the Sacramento Valley Air Basin –
SVAB).
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Figure 15-1
Aerial View of Sacramento and San Joaquin Valley
Air pollution is directly related to a region's topographic features. The valley floor slopes up
gradually from Sacramento (elevation 17 feet) northward to Redding (580 feet). The entire air
basin is 200 miles long in a north-south direction, and has a maximum width of 150 miles. The
valley floor, however, averages only about 50 miles in width. The Sutter Buttes, rising to 2,117
feet and covering approximately 80 square miles, stand out on the valley floor in Sutter County.
Local meteorological conditions are greatly influenced by the topography surrounding the
Sacramento Valley. For example, wind directions and speeds reflect the channeling effect of the
mountain ranges that exist on three sides of the air basin. The summertime marine air from San
Francisco Bay enters the Sacramento Valley through the Carquinez Straits and the Cordelia Gap
in the Coast Range. The penetration route is reflected in the maximum surface temperatures in
the valley. The relatively cool tongue of marine air often extends into Sacramento County. The
marine penetration path also influences the inversion characteristics in the valley.
Local climatological effects, including wind speed and direction, temperature, inversion layers,
and precipitation and fog, can exacerbate the air quality problem in the SVAB. These factors are
described below.
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Wind Speed and Direction
Wind speed and direction play an important role in dispersion and transport of air pollutants.
Wind at the surface and aloft can disperse pollution by mixing vertically and by transporting it to
other locations. Ozone is classified as a “regional” pollutant in part because of the time required
for ozone formation. Ozone precursors can be transported well away from the source area before
ozone concentrations peak. Respirable particulate matter (PM-10) is also considered a regional
pollutant in part because of its tendency to remain suspended in the air over long periods of time.
Some other primary pollutants, such as carbon monoxide (CO), are classified as “localized”
pollutants in part because they tend to dissipate easily and therefore usually form high
concentrations only when wind speed is low.
The predominant surface wind flows in the Sacramento Valley are along a Northeast-southwest
axis, channeled by the Coast Range and Sierra Nevada on either side of the valley. North winds
of varying velocities are frequent throughout the year. They occur at intervals of one to three
weeks during the summer and occasionally during the summer, raising temperatures and
lowering relative humidity to 10 percent or less. Winds from the southeast tend to be cool winds
and in the winter bring in cold, moisture-laden air. Southeast winds are usually of marine origin,
passing through the Golden Gate and entering the valley through the Carquinez Straits. During
the summer months, intrusions of marine air exert less effect on Butte County’s climate than on
counties to the south. It takes significant wind velocities to penetrate as far as Butte County.
There appears to be a barrier of eddy currents in the vicinity of the Sutter Buttes that turn low
velocity winds across the valley and back down the other side.
Temperature
Temperature and solar radiation are particularly important in the chemistry of ozone formation.
Ozone is formed in a photochemical reaction requiring sunlight. Generally, the higher the
temperature, the more ozone formed, since reaction rates increase with temperature. However,
extremely hot temperatures can “lift” or “break” the inversion layer. Typically, if the inversion
layer does not lift to allow the buildup of contaminants to be dispersed over the tops of the
mountains, the ozone levels will peak in the late afternoon, sometimes as late as 3 to 7 p.m. If the
inversion layer breaks and the resultant afternoon winds occur, the ozone will peak in the early
afternoon and decrease in the later afternoon as the contaminants get transported to the north.
Temperature is not as important to formation of high CO or PM-10 levels.
The varied topography of Butte County creates a variety of climatic regimes, varying mainly
with elevation. The valley floor and lower foothills have a typical Mediterranean climate with
hot, dry summers and cool, wet winters. The higher elevations experience cooler summers and
more rigorous winters.
Maximum temperatures in the Sacramento Valley and foothills have reached 118 F and regularly
exceed 105 F in July and 100 F in August. Minimum temperatures during this period average 62
F, but nighttime temperatures may remain above 90 F during periods of hot dry north winds. The
average annual temperature in the valley is 75 F. The mean lowest winter temperature is 24 F
temperatures. In Paradise, at an elevation of 2000 feet, maximum temperatures have reached 108
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F, but average July-August maximum temperatures are 100 F. The average annual high
temperature is 69 F. A low temperature of 20 F has been reached but the mean lowest
temperature is 26 F. The average annual temperature in Paradise is 59 F.
Temperature Inversions
The vertical dispersion of air pollutants in the SVAB is limited by the presence of persistent
temperature inversions. Because of expansion cooling of the atmosphere, air temperature usually
decreases with altitude. A reversal of this atmospheric state, where the air temperature increases
with height, is termed an inversion. Figure 15-2 depicts a typical temperature inversion.
Inversions can exist at the surface, or at any height above the ground. The height of the base of
the inversion is known as the “mixing height.” This is the level to which pollutants can mix
vertically.
Inversions occur in the Sacramento Valley with great frequency in all seasons. The most severe,
as far as ventilation is concerned, occurs in the late summer and the fall months. During this
season, the upper air is warmer than in spring and summer, and daytime surface heating is
diminished. Under such conditions the atmosphere is described as “stable” in meteorological
terms. This means that vertical air currents and the accompanying dispersion of air contaminants
are severely limited.
Although summer inversions are strong and frequent in the valley, they are generally less
troublesome than those in the fall. The summertime inversions are often the result of marine air
pushing under an overlying warm air mass. These are termed “marine inversions” and are
generally accompanied by brisk afternoon winds that provide good ventilation. In contrast, many
of the autumn inversions are the result of warm air subsiding in a high-pressure cell. The
accompanying light winds do not provide adequate dispersion.
Mountain and foothill areas are ordinarily not affected by the valley inversion. The inversion
base is usually below 1,500-foot level; valley air contaminants are largely confined to areas
below that elevation.
Air above and below the inversion base does not mix because of differences in air density. Warm
air above the inversion is less dense than below the base. The inversion base represents an abrupt
density change where little exchange of air occurs. This phenomenon is similar to that of the
abrupt density change that separates skim and whole milk. Inversion layers are significant in
determining ozone formation and CO and PM-10 concentrations. Ozone and its precursors will
mix and react to produce higher concentrations under an inversion, and inversions trap and hold
directly emitted pollutants like CO. PM-10 is both directly emitted and created in the atmosphere
as a chemical reaction. Concentration levels are directly related to inversion layers due to the
limitation of mixing space.
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Figure 15-2
Temperature Inversion
WIND CURRENTS (WARM AIR)
POLLUTANTS
IN COLD
AIR
INVERSION LAYER
Cold air drops to the valley floor and is trapped by warm air traveling over the
mountains. This is analogous to putting a lid over the valley which traps all of the
pollutants in the cold air mass.
Precipitation and Fog
Precipitation and fog tend to reduce or limit some pollutant concentrations. Ozone needs sunlight
for its formation, and clouds and fog block the required radiation. CO is slightly water-soluble so
precipitation and fog tends to “reduce” CO concentrations in the atmosphere. PM-10 is
somewhat “washed” from the atmosphere by precipitation.
Heavy fog may occur periodically from late fall through early spring. Low, dense fogs are most
common in the winter months and may persist for several days. Light moderate fogs are more
common during the cold months. Most of these fogs are below an elevation of 1000 feet and the
foothill and mountain areas remain clear and sunny during many valley fog periods.
Annual precipitation in Butte County varies from 18 inches in the western boundary to 80 inches
in high elevation areas in the northeastern and southern portions. The foothills receive 35-45
inches annually. Snowfalls occur irregularly on the valley floor and regularly at the higher
elevations. Paradise usually receives measurable snowfall each winter.
The rain shadow effect is another process wherein local topography influences weather. Rain
shadows occur on the lee sides of mountain ranges and are areas that receive less precipitation
than the windward side. The western part of the valley, situated on the lee side of the Coast
Ranges, is considerably drier than the eastern portion.
The winds and unstable air conditions experienced during the passage of storms result in periods
of low pollutant concentrations and excellent visibility. Between winter storms, high pressure
and light winds allow cold moist air to pool on the SVAB floor. This creates strong low-level
temperature inversions and very stable air conditions. This situation leads to valley fog
formation. The formation of natural fog is caused by local cooling of the atmosphere until it is
saturated (dew point temperature). This type of fog, known as radiation fog, is more likely to
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occur inland. Cooling may also be accomplished by heat radiation losses or by horizontal
movement of a mass of air over a colder surface. This second type of fog, known as advection
fog, generally occurs along the coast.
Conditions favorable to fog formation are also conditions favorable to high concentrations of CO
and PM-10. Ozone levels are low during these periods because of the lack of sunlight to drive the
photochemical reaction. Maximum CO concentrations tend to occur on clear, cold nights when a
strong surface inversion is present and large numbers of fireplaces are in use. A secondary peak
in CO concentrations occurs during morning commute hours when a large number of motorists
are on the road and the surface inversion has not yet broken.
The water droplets in fog, however, can act as a sink for CO and nitrogen oxides (NOx),
lowering pollutant concentrations. At the same time, fog could help in the formation of
secondary particulates such as ammonium sulfate. These secondary particulates are believed to
be a significant contributor of winter season violations of the PM-10 and potentially PM-2.5
standards.
15.4 AIR QUALITY REGULATION
Introduction
All levels of government have some responsibility for protecting air quality. This section outlines
the responsibilities of federal, state, regional, and local government agencies in air quality
matters and attempts to explain how they interact.
Federal
At the federal level, the Environmental Protection Agency (EPA) has been charged with
implementing national air quality programs. The EPA's air quality mandates are drawn primarily
from the Federal Clean Air Act (FCAA). The President first signed the FCAA into law in 1970.
The Act was substantially amended in 1977 and again in 1990.
The EPA deals with global, international, national, and interstate air pollution issues. Its primary
role at the state level is one of oversight of state air quality programs. The EPA sets federal
vehicle and stationary source emission standards and provides research and guidance in air
pollution programs.
The FCAA required the EPA to set National Ambient Air Quality Standards (NAAQS) for
several air pollutants on the basis of human health and welfare criteria. Two types of NAAQS
have been established: primary standards, which protect public health, and secondary standards,
which protect the public welfare from non-health-related adverse effects such as visibility
reduction. Primary NAAQS were established for the following “criteria” air pollutants (so called
because they were established on the basis of health criteria): carbon monoxide (CO); ozone;
PM-10; PM-2.5 nitrogen dioxide (NO2); sulfur dioxide (SO2); and lead.
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The primary NAAQS standards are intended to protect, with an adequate margin of safety, those
persons most susceptible to respiratory distress, such as people suffering from asthma or other
illness, the elderly, very young children, or others engaged in strenuous work or exercise. Table
4.1 presents the NAAQSs.
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TABLE 15-2
NATIONAL AND CALIFORNIA AMBIENT AIR QUALITY STANDARDS
Air Pollutant Averaging Time Units1 Standards2
CAAQS3 NAAQS4
Ozone (O3) 8 hour5
1-hour6
ppm
ppm
—
0.09 0.08
0.12
Carbon Monoxide (CO) 8 hour
1 hour
ppm
ppm
9.0
20
9
35
Nitrogen Dioxide (NO2) Annual Average
1 hour
ppm
ppm
—
0.25
0.053
—
Sulfur Dioxide (SO2) Annual Average
24 hours
1 hour
ppm
ppm
ppm
—
0.04
0.25
0.03
0.14
—
Fine Particulate Mater (PM-2.5)7 Annual Average8
24 hours9
µg/m3
µg/m3
12
—
15
65
Respirable Particulate Matter (PM-10) Annual
24 hours10
µg/m3
µg/m3
2011
50
5012
150
Lead (Pb) 30 Day Average
Calendar Quarter
µg/m3
µg/m3
1.5
—
—
1.5
Sulfates (SOx) 24 hour µg/m3 25 —
Visibility Reducing Particulates (VSP) 8 hour — 13 —
Vinyl Chloride (chloroethane) 24 hour ppm 0.01 —
Hydrogen Sulfide (H2S) 1 hour ppm 0.03 —
Source: California Air Resources Board, website www.arb.ca.gov;
The FCAA required each state to prepare an air quality control plan referred to as the State
Implementation Plan (SIP). The Federal Clean Air Act Amendments of 1990 (FCAAA)
1 Concentration expressed in the following units: ppm refers to parts per million by volume and µg/m3 is micrograms per cubic meter.
2Only the primary standards are established to protect the public health and are the most stringent federal standards
3 California Ambient Air Quality Standard (CAAQS) for ozone, CO, SO2 (1-hour averaging period), NO2, and PM-10 are not to be
exceeded.
4 National Ambient Air Quality Standard (NAAQS) (other than ozone, PM, and those based on annual averages or annual arithmetic
means) are not to be exceeded more than once per year.
5 The 8-hour standard is presented here for information purposes only. The Standard is established but implementation criteria are still
to be determined at this time. The federal standard will be evaluated on the 4th highest (daily maximum) 8-hour average per year,
averaged over 3 years.
6 The federal 1-hour standard will be attained when the 4th highest (daily maximum) 1-hour average per year, averaged over 3 years, is
equal to or less than the standard. Once attained this standard will no longer be in effect.
7 The PM-2.5 standard is presented here for information purposes only. Implementation is in the data-gathering phase.
8 The annual standard will be met when the 3-year average of the annual arithmetic mean PM-2.5 concentration is less than or equal to
15 µg/m3.
9 The 24-hour standard will be met when the 3-year average of the 98th percentile of 24-hour PM-2.5 concentration is less than or equal
to 65 µg/m3.
10 The 24-hour standard is attained when 99 percent of the daily concentrations, averaged over 3 years, are equal to or less than the
standard.
11 The state PM-10 annual standard is attained when the expected annual geometric mean concentration is less than or equal to 30
µg/m3.
12 The federal PM-10 annual standard is attained when the expected annual arithmetic mean concentration is less than or equal to 50
µg/m3.
13 In sufficient amount to produce an extinction coefficient of 0.23 per kilometer due to particles when the relative humidity is less than
70 percent.
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additionally required states containing areas that violate NAAQS to revise their SIPs to
incorporate additional control measures to reduce air pollution. The SIP is a document that can
be periodically modified to reflect the latest emissions inventories, planning documents, and
rules and regulations of air basins as reported by the agencies with jurisdiction over them. The
EPA has responsibility to review all state SIPs to determine if they conform to the mandates of
the FCAAA and will achieve air quality goals when implemented. If the EPA determines a SIP
to be inadequate, it may prepare a Federal Implementation Plan (FIP) for the nonattainment area
and may impose additional control measures. Failure to submit an approvable SIP or to
implement the plan within mandated timeframes can result in sanctions being applied to
transportation funding and stationary air pollution sources in the air basin.
State
The California Air Resources Board (ARB) is the agency responsible for coordination and
oversight of state and local air pollution control programs in California and for implementing the
California Clean Air Act (CCAA), enacted in 1988. The ARB was created in 1967 from the
merging of the California Motor Vehicle Pollution Control Board and the Bureau of Air
Sanitation and its laboratory.
The ARB has primary responsibility in California to develop and implement air pollution control
plans designed to achieve and maintain the NAAQS established by the EPA. Whereas the ARB
has primary responsibility and produces a major part of the SIP for pollution sources that are
statewide in scope, it relies on the local air pollution control and air quality management districts
to provide additional strategies for sources under their jurisdiction. The ARB combines its data
with all local district data and submits the completed SIP to the EPA. The SIP consists of the
emissions standards for vehicular sources set by the ARB, and attainment plans adopted by the
local districts and approved by the ARB.
States may establish their own standards, provided the state standards are at least as stringent as
the NAAQS. California has established California Ambient Air Quality Standards (CAAQS)
pursuant to California Health and Safety Code (CH&SC) [§ 39606(b)] and its predecessor
statutes. Table 4.1 also presents the CAAQSs.
On June 20, 2002, the Air Resources Board approved revision to the PM-10 annual average
standard to 20 ug/m3 and to establish an annual average standard for PM-2.5 of 12 ug/m3. These
standards took effect in February 2003.
The CH&SC [§ 39608] requires the ARB to “identify” and “classify” each air basin in the state
on a pollutant-by-pollutant basis. Subsequently, the ARB designated areas in California as
nonattainment based on violations of the CAAQSs. Designations and classifications specific to
the SVAB can be found in the next section of this document. Areas in the state were also
classified based on severity of air pollution problems. For each nonattainment class, the CCAA
specifies air quality management strategies that must be adopted. For all nonattainment
categories, attainment plans are required to demonstrate a five-percent-per-year reduction in
nonattainment air pollutants or their precursors, averaged every consecutive three-year period,
unless an approved alternative measure of progress is developed. In addition, air districts in
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violation of CAAQS are required to prepare an Air Quality Attainment Plan (AQAP) that lays
out a program to attain and maintain the CCAA mandates.
Other ARB duties include monitoring air quality. The ARB has established and maintains, in
conjunction with local air pollution control districts and air quality management districts, a
network of sampling stations (called the State and Local Air Monitoring [SLAMS] network),
which monitor what pollutants are present in the ambient air and at what levels.. Further duties of
the ARB are setting emissions standards for new motor vehicles, consumer products, small
utility engines, and off-road vehicles. In many cases, California standards are the toughest in the
nation. Table 15-3 presents a list of monitoring stations active in the SVAB at any time since
1990 through the end of 2003, except as noted below.
To access real time Air Quality Monitoring Data for Butte County or any monitoring site in
California, go to the following link http://www.arb.ca.gov/aqd/aqinfo.htm.
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TABLE 15-3
AIR QUALITY MONITORING DATA IN THE NORTHERN SVAB (ACTIVE AS NOTED BELOW)
Butte County O3 PM-10 PM-2.5 CO NO2 Toxics Operating
Agency
Bigg-9th & C Street 87-90
Chico-Manzanita 77-01 92-03 98-03 77-03 77-03 92-03 ARB
Chico-Salem Street
(closed 2/98)
89-92 81-98 ARB
Gridley Cowee Avenue 92-94 00-03 ARB
Paradise Airport Road 00-03 ARB
Paradise Fire Station 78-79 01-03 ARB
Colusa County O3 PM-10 PM-2.5 CO NO2 Toxics Operating
Agency
Colusa- Fairgrounds 80-96 86-03 98-03 ARB
Colusa-Sunrise Blvd 96-03 86-03 98-03 ARB
Glenn County O3 PM-10 PM-2.5 CO NO2 Toxics Operating
Agency
Willows-E Laurel Street 94-03 94-03 ARB/District
Willows-N Villa Avenue 79-94 86-94 District
Shasta County O3 PM-10 PM-2.5 CO NO2 Toxics Operating
Agency
Anderson-North Street 93-00 93-03 District
Burney-Siskiyou 89-92 89-93 89-92 District
Redding-Continental 84-90 87-88 86-90 District
Redding-Health Dept 90-03 86-03 98-03 92-94 90-92 District
Sutter County O3 PM-10 PM-2.5 CO NO2 Toxics Operating
Agency
Pleasant Gove-4 mi SW 82-02 ARB
Sutter Buttes 93-03 ARB
Yuba City-Almond Street 89-03 89-03 98-03 91-03 91-03 ARB
Tehama County O3 PM-10 PM-2.5 CO NO2 Toxics Operating
Agency
Red Bluff-Oak Street 96-03 District
Red Bluff-Riverside
Drive
86-03 District
Regional
State law recognized that air pollution does not respect political boundaries and therefore
required the ARB to divide the state into separate air basins that each have similar geographical
and meteorological conditions [CH&SC §39606(a)]. Originally air pollution was regulated
separately by county air pollution control districts. Although this is still the practice in most
counties in California, including Butte County, many county agencies began to realize that air
quality problems are best managed on a regional basis and began to combine their regulatory
agencies into regional agencies such as the Bay Area, South Coast and San Joaquin Valley Air
Quality Management Districts.
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Air districts have the primary responsibility for control of air pollution from all sources other
than emissions directly from motor vehicles, which are the responsibility of the ARB and the
EPA. Air districts adopt and enforce rules and regulations to achieve state and federal ambient
air quality standards and enforce applicable state and federal law.
The BCAQMD’s Role
The BCAQMD has jurisdiction over air quality matters in Butte County. The BCAQMD
(formally a department of Butte County government) is now, under California law, an
independent special district. The Air Quality Governing Board comprises the five Butte County
Supervisors plus five elected members appointed by each of the county’s five cities. The Board
establishes policy and approves new rules. The District Board also appoints the Air Pollution
Control Officer and District Hearing Board. The Board meets the 4th Thursday monthly at the
City Council Chambers in Chico.
Until the passage of the CCAA, the air districts’ primary role was the control of stationary
sources of pollution such as industrial processes and equipment that stayed within the districts’
jurisdictional boundaries. With the passage of the CCAA and FCAAA, air districts were
additionally required to implement transportation control measures such as employer-based trip
reduction programs. They were also encouraged to adopt indirect source control programs to
reduce mobile source emissions. These mandates created the necessity for the BCAQMD to
work closely with cities and counties and with regional transportation planning agencies to
develop new programs.
The BCAQMD works with the Butte County Association of Government (BCAG) to ensure a
coordinated approach in the development and implementation of transportation plans throughout
the county. This coordination insures compliance with pertinent provisions of the federal and
state Clean Air Acts, as well as related transportation legislation (such as the Intermodal Surface
Transportation Efficiency Act, Transportation Conformity, and Transportation Improvement
Plans).
The BCAQMD continues to work with the public, the business sector, and local governments to
protect the public’s health and provide for the improvement of the county’s air quality resources.
Air Quality Plans
The BCAQMD has adopted several attainment plans in an attempt to achieve state and federal
air quality standards. The BCAQMD must continuously monitor its progress in implementing
attainment plans and must periodically report to the ARB and the EPA. It must also periodically
revise its attainment plans to reflect new conditions and requirements in accordance with
schedules mandated by the CCAA and FCAAA.
The CCAA requires districts to adopt air quality attainment plans and to review and revise their
plans to address deficiencies in interim measures of progress once every three years. The
BCAQMD’s Air Quality Attainment Plan was adopted in 1991 and updated in 1994, 1997, 2000
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and most recently in 2003. The 2003 Attainment Plan is available on the Districts website at
http://www.bcaqmd.org/air.cfm.
The Chico Urbanized Area was designated as nonattainment for the federal 8-hour carbon
monoxide (CO) standard in 1991. The State Air Resources Board (ARB) adopted a State
Implementation Plan revision in 1996 documenting that ten areas, including Chico, had attained
the federal 8-hour CO air quality standard between 1992-1995 and demonstrating how they
would continue to maintain compliance with that standard. The U.S. Environmental Protection
Agency (U.S. EPA) approved the 1996 SIP revision and formally redesignated these ten areas to
attainment in 1998.
BCAQMD Rules, Regulations, and Programs
The BCAQMD's primary means of implementing air quality plans is by adopting rules and
regulations. The CH&SC [§40001 and 42300 et. seq.] authorizes districts to adopt rules and
regulations and to pursue civil and criminal penalties for violations. The law allows for fines and
civil penalties of up to $50,000 per day and imprisonment in the county jail for up to one year.
The BCAQMD has adopted rules on sources ranging from Architectural Coatings (Rule 230) to
Orchard Heaters (Rule 209) and Residential Wood Combustion (Rule 207) to Cutback &
Emulsified Asphalt (Rule 231). The BCAQMD rulebook contains more than 120 rules and more
are scheduled for rule development over the next few years.
In addition, the BCAQMD has identified strategies for reducing emissions generated by indirect
sources in the 1997 Air Quality Attainment Plan. These strategies include enhancing BCAQMD
California Environmental Quality Act (CEQA) participation, encouraging all cities and county to
adopt an air quality element or air quality policies as part of their General Plan, and
implementing a new and modified indirect source review (ISR) program. The BCAQMD now
actively reviews and comments on CEQA documents prepared by lead agencies and suggests
mitigation measures to reduce air quality impacts.
Toxic Air Pollutants
Legislation such as AB 1807 Tanner Air Toxics Act, AB 2588 Air Toxics “Hot Spots”
Information and Assessment Act, AB 3205 Toxic Emissions Near Schools, SB 1731 “Hot Spots”
Risk Reduction Mandates, and the Federal Clean Air Act Amendments Title III mandate the
BCAQMD to implement a comprehensive toxic air emission program. The District has
developed a Toxics New Source Review Rule 1106 for complying with Federal Clean Air Act
Section 112(g), which is designed to ensure that emission of toxic air pollutants do not increase
if a major source is constructed or reconstructed. AB 2588 requires the BCAQMD to develop a
uniform approach to catalogue the emissions of more than 700 toxic compounds. The District
program is designed to identify, characterize and inventory various sources of air toxic
compounds, evaluate the potential health risks to the public and provide information to the public
on exposures.
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Public Education Program
The BCAQMD has also adopted a number of voluntary air quality programs. Examples include
the Smoking Vehicle Program, District Air Quality Education Program, and publishing a
quarterly newsletter Stratus Status. The District also publishes and distributes a Clean Air Kids
quarterly newsletter to the elementary schools within Butte County and members of the Clean
Air Kids Club. The District has sponsored for the past several years a countywide Clean Air Kids
calendar contest for elementary students. The 2003 Clean Air Kids calendar featured student’s
artistic ideas about how they can reduce air pollution. Although these programs are voluntary,
they provide an important link to local government and the public.
Agricultural Open Burning
Agricultural and open burning has been an important waste management tool for farmers, forest
and wildland managers, and residents in Butte County. Agricultural burning is not prohibited
under state law. However, ARB and local air districts strictly regulate this activity. Responsible
compliance with the rules for agricultural and open burning minimizes the impact on public
health and preserves the region’s economy.
Agricultural burning is the open burning of vegetative materials produced from commercial
growing and harvesting crops or raising fowl or animals. Agricultural waste also includes the use
of open outdoor fires used in the operation or maintenance of a system for the delivery of water,
wildland burning, forest management burning including silvaculture and timber operations, and
prescribed burning.
Agricultural burning helps farmers remove crop residues left in the field after harvesting grains
such as rice, wheat or corn, and for orchard prunings and removal. Burning is also helpful in
removing weeds, preventing disease, and controlling pests. For some crops, particularly rice,
burning of straw, or stubble is the most efficient and effective way to control disease. In the
Sacramento Valley, rice has historically accounted for much of the local agricultural burning,
with corn and wheat close behind.
Prescribed burning is a planned fire and is utilized by public and private land managers for
vegetation management. Fire has a natural role in forest ecosystems and is used to minimize
catastrophic wildfires.
As a source of air pollution, smoke can pose a threat to human respiratory systems: Smoke
particles - very small droplets of condensed organic vapors, unburned fuel, soot and ash that
escape from fire - can cause and aggravate to lung damage, chronic lung disease, and cancer.
Smoke contains ozone-forming compounds (volatile organic compounds and oxides of nitrogen)
and significant amounts of fine particles and other pollutants. Toxic residue from compounds in
smoke can remain in the air for weeks; if inhaled, it can lodge deep in the lungs, causing
irritation and coughing.
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Pollutants from open burning are believed to contribute less than seven percent to Butte County’s
ground-level ozone and less than nine percent to PM-10 (particulate matter less than 10 microns
in diameter). The primary source of regional pollution continues to be motor vehicles at nearly
70 percent. However, as part of the effort to reduce air pollution in the Sacramento Valley Air
Basin, agricultural burning is controlled through a process of permits, rules, and regulations.
Penalties for violating California air pollution regulations can be expensive – as much as $50,000
per day. Keeping agricultural burning operations within the legal requirements not only avoids
costly penalties, but also helps provide a healthier environment for the public.
A BCAQMD Burn Permit is required for burning agricultural waste, land clearing waste, or
levee, ditch, timber harvesting operations, prescribed burning, and right-of-way clearing waste.
Burning is allowed only on permissive burn days, when forecasted weather conditions create
enough air movement to permit good smoke dispersal. Burning is also restricted to certain times
of the day. All burn permit holders must also comply with local fire protection agency permit
requirements.
The ARB determines permissive burn days and the number of acres allocated for agricultural and
open burning based on meteorological and air quality factors. When conditions have been met,
ARB authorizes burning in the Sacramento Valley Air Basin.
The Sacramento Valley Basinwide Air Pollution Control Council, comprised of nine air districts,
develops a smoke management programs (SMP), subject to ARB approval. The SMP specifies
requirements for determining agricultural burn hours and daily, basinwide acreage allocations,
commensurate with weather conditions and air quality levels.
The BCAQMD handles the day-to-day implementation of the agricultural burning program:
issuing burn permits, informing growers and land managers of when and how much they can
burn, conducting complaint investigations, conducting enforcement procedures in violation
cases, and publishing educational materials on air quality issues.
The Rice Straw Burning Reduction Act was enacted in 1991 by the California Legislature to
phase down – but not phase out – burning of rice straw in the Sacramento Valley Air Basin.
Beginning in 2001, rice straw burning was limited to 25 percent of the planted acres. In order to
burn, however, growers must show proof of crop loss due to disease, and only 125,000 acres per
year will be allocated basinwide. Because of the phase down, growers are seeking alternatives to
burning. The SMP is also contributing to a decrease in the total percentage of local acreage being
burned b limiting burning on poor air quality days.
Residential/Dooryard Open Burning
Residential or Dooryard burning is the burning of vegetative waste in a 4’ x 4’ pile. The local,
State and federal fire protection agencies, and BCAQMD regulate Residential or Dooryard
burning. Residential or Dooryard burning is allowed only on permissible burn days, as
determined by the BCAQMD. Burn day information is available 7 days a week from the burn
line 896-2537. A person wishing to burn must confirm the burn day status before burning.
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Commercial entities are allowed to use open burning if the burning is performed for the purpose
of fire hazard reduction to comply with local fire agencies, commercial land clearing for future
development and sale or fire hazard reduction.
Only vegetative waste or clean dry paper products may be burned in accordance with local fire
agency requirements. District Rule 300 and State law prohibit the burning of garbage, tires, trash,
construction materials, plastic, bedding or furniture, paint, rubber, cotton, wool, petroleum
products, other similar smoke or toxic fume producing items, and fireworks.
The ARB has identified the smoke and ash from burning residential waste produces a number of
toxic air pollutants. The ARB adopted the Residential Waste Burning Air borne Toxic Control
Measure, which takes effect January 1, 2004. The regulation restricts residential burning
statewide to the burning of dry, natural vegetation and prohibits the use of burn barrels. Burn
barrels have been prohibited because they were found to contain household garbage that
produces toxic smoke and fumes when burned.
15.5 AIR QUALITY IN BUTTE COUNTY AND THE SACRAMENTO
VALLEY AIR BASIN DISTRICTS
As discussed in the previous section, both the ARB and the EPA have established air pollution
standards in an effort to protect human health and welfare. Geographic areas are designated
“attainment” if these standards are met and “nonattainment” if they are not met. In addition, each
agency has several levels of classifications based on severity of the problem.
All northern Sacramento Valley Air Districts have been designated as “moderate” non-
attainment areas for the State standards for O3 and PM-10. Butte County is also designated as
nonattainment for PM2.5. In 1996 Butte County was designated as an attainment area for carbon
monoxide (CO). The table below shows the attainment status for Butte County for the primary
criteria pollutants.
TABLE 15-4
BUTTE COUNTY AMBIENT AIR QUALITY ATTAINMENT STATUS
Pollutant State Federal
1-hour Ozone Nonattainment Nonattainment Transitional
8-hour Ozone --Proposed Basic Nonattainment
Carbon Monoxide Attainment Attainment
Nitrogen Dioxide Attainment Attainment
Sulfur Dioxide Attainment Attainment
Inhalable Particulates (PM10)Nonattainment Attainment
Inhalable Particulates (PM2.5) Nonattainment Attainment
Ozone (O3) violations are caused within the NSVAB, in part, by combustion sources. The
primary emission source is the internal combustion engine. The O3 problem is further aggravated
by transport from the Broader Sacramento Area (BSA), which is comprised of Sacramento
County and portions of El Dorado, Placer, Sutter and Yolo Counties. Ozone is formed by a
photochemical reaction of nitrogen oxides (NOx) and reactive organic gases (ROG). These
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ozone precursors are emitted as part of the exhaust of internal combustion engines in the
NSVAB and BSA and transported northward via prevailing winds.
Due to the regional nature of the O3 problem and the fact that the NSVAB counties share the
same air basin with the BSA, the Attainment Plan is prepared in conjunction with the Basinwide
Air Pollution Control Council.
Butte County is proposed to be classified as a “basic” non-attainment area for the federal 8-hour
ozone NAAQS. The federal 1-hour ozone standard is expected to be revoked in mid 2005 when
the 8-hour ozone standard applies. Butte County will have three years to submit a plan, which
describes efforts to reduce ground-level ozone. The Clean Air Act requires basic areas to attain
the ozone standard as expeditiously as practicable, but no later than 2009. Nonattainment areas
with higher classifications must meet additional requirements and have later attainment
deadlines. Under the new 8-hour standard the Sacramento Metropolitan area is proposed as a
serious non-attainment area with 2013 as the maximum attainment date.
Air Pollutant Properties, Health Effects And Sources
Air pollution affects the health of everyone to some degree. The adverse health impacts from O3,
reactive organic gases (ROG), nitrogen oxide (NOx), CO, and PM-10 are described below.
Pollutant: Ozone
Description and Physical Properties: Ozone is a photochemical pollutant. That means it is not
emitted directly into the atmosphere, but is formed by a complex series of chemical reactions
between ROG, NOx, and sunlight. ROG and NOx are emitted from automobiles, solvents, and
fuel combustion, the sources of which are widespread throughout Butte County. In order to
reduce ozone concentrations, it is necessary to control the emissions of these ozone precursors.
Significant ozone formation generally requires an adequate amount of precursors in the
atmosphere and several hours in a stable atmosphere with strong sunlight. Ozone is considered a
regional air pollutant, which means it is generated over a large area and is transported and spread
by wind. In the NSVAB, ozone is a seasonal problem, typically occurring during the months of
May through October.
Effects: While ozone in the upper atmosphere protects the earth from harmful ultraviolet
radiation, high concentrations of ground level ozone can adversely affect the human respiratory
system. Many respiratory ailments, as well as cardiovascular disease, are aggravated by exposure
to high ozone levels. Ozone also damages natural ecosystems such as forests and foothill
communities, and damages agricultural crops and some man-made materials, such as rubber,
paint, and plastics. Symptoms include shortness of breath, chest pain when inhaling deeply,
wheezing and coughing. When ozone levels are high, people with lung disease (e.g., chronic
bronchitis, emphysema, and asthma) are particularly susceptible to adverse health impacts.
Ozone can impair people’s ability to breathe and cause shortness of breath, chest pain, wheezing,
and coughing. People with respiratory problems are most vulnerable, but even some healthy
people can be affected while engaging in moderate physical activity when ozone levels are high
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enough. Animal studies suggest that repeated exposure to high levels of ozone over several
months may permanently damage the lungs and cause chronic respiratory illness. (United States
EPA, March 1997). Other studies suggest that over time ozone permanently and irrevocably
alters lung tissue (Health & Clean Air Newsletter, Fall 2002).
Tests carried out on healthy adults and children undergoing heavy exercise have found that
exposure to ozone even below the federal health-based air quality standards results in a decrease
in the normal function of the lungs (American Lung Association, 1997).
Pollutant: Reactive Organic Gases (ROG)
Description and Physical Properties: Reactive organic gases, also known as volatile organic
compounds, are photochemically reactive hydrocarbons that are important for ozone formation.
This definition excludes methane, carbon monoxide, carbon dioxide, carbonic acid, metallic
carbides or carbonates, ammonium carbonates, methylene chloride, methyl chloroform, and
various chlorofluorocarbons (CFCs).
Effects: The main concern about ROG is its role in photochemical ozone formation. While some
compounds that make up ROG, such as benzene, a known carcinogen, are toxic, there are no
health standards for ROG separately.
Sources: The primary sources of ROG are mobile sources, solvents, surface coating, and waste
burning. Table 15-5 shows the 2001 ROG estimated annual average emissions14 for Butte
County.
TABLE 15-5
BUTTE COUNTY 2001 ROG EMISSIONS
Category tons/day % of total
Fuel Combustion 0.05 .2%
Cleaning and Surface Coating 1.89 6.5%
Petroleum Production and Marketing 0.63 2.2%
Industrial Processes 0.39 1.3%
Solvent Evaporation 6.43 22.1%
Residential Fuel Combustion 1.35 4.7%
Waste Burning and Disposal 1.64 5.7%
Fires 0.01 .03%
Cooking 0.03 .1%
Mobile Sources 16.46 56.7%
Natural Sources 0.13 .47%
Total 29.01 100%
14 Data from the Emission Inventory for 2001, published by the ARB on their website (www.arb.ca.gov).
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Pollutant: Nitrogen Oxides (NOx)
Description and Physical Properties: NOx is a family of gaseous nitrogen compounds and are
precursors to ozone formation. The major component of NOx, nitrogen dioxide (NO2), is a
reddish-brown gas that is toxic at high concentrations. NOx results primarily from the
combustion of fossil fuels under high temperature and pressure.
Effects: Health effects associated with NOx are an increase in the incidence of chronic
bronchitis and lung irritation. Chronic exposure to NO2 may lead to eye and mucus membrane
aggravation, along with pulmonary dysfunction.15 NOx can cause fading of textile dyes and
additives, deterioration of cotton and nylon, and corrosion of metals due to production of
particulate nitrates.16 Airborne NOx can also impair visibility. NOx is a major component of acid
disposition in California.
Sources: On-road motor vehicles are the major sources of this air pollutant, which emits
approximately 91 percent of the total NOx released in Butte County. Table 15-6 shows the 2001
NOx estimated annual average emissions.
TABLE 15-6
BUTTE COUNTY 2001 NOX EMISSIONS
Category tons/day % of total
Fuel Combustion 1.13 4.8%
Industrial Processes 0.10 0.4%
Residential Fuel Combustion 0.70 3.0%
Waste Burning and Disposal 0.14 0.6%
Mobile Sources 21.56 90.60%
Natural Sources 0.15 0.6%
Total 23.78 100%
Pollutant: Carbon Monoxide (CO)
Description and Physical Properties: CO is an odorless, colorless gas that is highly toxic. It is
formed by the incomplete combustion of fuels and is emitted directly into the air (unlike ozone).
Under most conditions, CO does not persist in the atmosphere and is rapidly dispersed. CO
exceedances are most likely to occur in the winter, when relatively low inversion levels trap
pollutants near the ground and concentrate the CO. Since CO is somewhat soluble in water;
normal winter conditions of rainfall and fog can suppress CO concentrations.
Effects: Carbon monoxide binds strongly to hemoglobin, the oxygen-carrying protein in blood,
and thus reduces the blood’s capacity for carrying oxygen to the heart, brain, and other parts of
the body. At high concentrations, CO can cause heart difficulties in people with chronic diseases,
can impair mental abilities, and can even cause death.
15 Sittig, Marshall, Handbook of Toxic and Hazardous Chemicals and Carcinogens, Second Edition, 1985.
16 Hodges, Laurent, Environmental Pollution, second edition, New York: Holt, Rhinehart, and Winston, 1977.
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Sources: The main source of CO in Butte County is on-road motor vehicles. Motor vehicles
contribute approximately 73 percent of total CO emissions. Other CO sources include residential
and waste burning. Because most of these CO sources are the indirect result of urban
development, most emissions and unhealthful CO levels occur in major urban areas. Table 15-7
shows the 2001 CO estimated annual average emissions for Butte County.
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Final Draft August 8, 2005
Butte County General Plan Background Report
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TABLE 15-7
BUTTE COUNTY 2001 CO EMISSIONS
Category tons/day % of total
Fuel Combustion 2.5 2.5%
Industrial Processes 0.14 .08%
Residential Fuel Combustion 19.30 11.50%
Waste Burning and Disposal 19.61 11.69%
Fires 0.11 .07%
Mobile Sources 122.74 72.17%
Natural Sources 3.34 1.99%
Total 167.75 100%
Pollutant: Particulate Matter (PM-10 and PM-2.5)
Description and Physical Properties: Suspended particulate matter (airborne dust) consists of
particles small enough to remain suspended in the air for long periods. Respirable particulate
matter (PM-10 and PM-2.5) includes particulates of 10 microns or less in diameter — those
which are small enough to be inhaled, pass through the respiratory system, and lodge in the
lungs, with resultant health effects.
PM-10 and PM-2.5 are comprised of dust, sand, salt spray, metallic, and mineral particles,
pollen, smoke, mist, and acid fumes. Also of importance are sulfate (SO4) and nitrates (NO3),
which are secondary particles, formed as precipitates from photochemical reactions of gaseous
sulfur dioxide (SO2) and NOx in the atmosphere.
The actual composition of PM-10 and PM-2.5 varies greatly with time and location. It depends
on the sources of the material and meteorological conditions.
Effects: Acute and chronic health effects associated with high particulate levels include the
aggravation of chronic respiratory diseases, heart and lung disease, and coughing, bronchitis, and
respiratory illnesses in children. Mortality studies have shown a statistically significant direct
association between mortality and daily concentrations of particulate matter in the air.17 In a
study linking cardiopulmonary mortality and long-term exposure to fine particulate pollution the
authors conclude: “The findings of this study provide the strongest evidence to data that long-
term exposure to fine particulate air pollution common to many metropolitan areas is an
important risk factor for cardiopulmonary mortality.”18 Non-health-related effects include
reduced visibility and soiling of buildings.
17 Schenker, Marc, "Pollution and Mortality", New England Journal of Medicine, Volume 329, Number 24,
December 9, 1993.
18 Pope, C. A. III, Burnett, R.T., Thun, N.J., Calle, E.E., Krewski, D., Ito, K., Thruston, G.D. “Lung Cancer,
Cardiopulmonary mortality, and long-term exposure to fine particulate air pollution” JAMA 2002: Vol. 287; 1132-
1141.
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Sources: Generally speaking, PM-2.5 sources tend to be combustion sources like vehicles,
power generation, industrial processes, and wood burning, while PM-10 sources include these
same sources plus roads and construction/farming activities. Fugitive windblown dust and other
area sources also represent sources of airborne dust in the NSVAB. Table 15-8 shows the 2001
PM-10 inventory for Butte County. A PM-2.5 inventory will be developed as data becomes
available.
TABLE 15-8
BUTTE COUNTY 2001 PM-10 EMISSIONS
Category tons/day % of total
Fuel Combustion 0.11 .35%
Industrial Processes 3.70 11.68%
Residential Fuel Combustion 2.93 9.25%
Waste Burning and Disposal 2.26 7.14%
Unpaved Road Dust 10.28 32.46%
Paved Road Dust 3.13 9.88%
Farming Operations 5.73 18.09%
Construction and Demolition 1.58 5.0%
Mobile Sources 0.92 2.9%
Wildfires 0.65 2.05%
Fugitive Dust 0.28 .88%
Cooking 0.10 .32%
Total 31.67 100%
Specific Annual Air Quality Data
Introduction
The ARB and some air districts maintain a network of stations that measure the levels of criteria
pollutants in the ambient air. The pollutants of concern for the NSVAB are those that are
designated nonattainment. Subsequently, data presented in this section are detailed air quality
information for ozone and PM-10 only.
Air Quality Data Tables – Explanatory Notes
The air quality data tables present data from air monitoring stations in the NSVAB for years
2001 through 2003.
Table 15.9 depicts, by area within Butte County, 3-year ozone air quality data including:
maximum 1-hour and 8-hour concentrations; days above State standard; days above national 1-
hour and 8-hour standard.
Table 15.10 depicts, by area within Butte County, three-year PM10 air quality statistics
including: Maximum 24-hour Concentration; Maximum Annual Geometric and Arithmetic
Mean; Estimated Days Above State 24-hour Standard; and Days Above National 24-hour
Standard.
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Final Draft August 8, 2005
Butte County General Plan Background Report
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TABLE 15.9A
OZONE TRENDS SUMMARY: BUTTE COUNTY - CHICO-MANZANITA AVENUE
Days Above Standard 1-Hour 8-Hour
Year 1-Hour State 1-Hour Nat’l 8-Hour Nat’l Maximum Maximum
2003 0 0 2 0.092 0.076
2002 2 0 0 0.100 0.083
2001 0 0 2 0.098 0.087
TABLE 15.9B
OZONE TRENDS SUMMARY: BUTTE COUNTY – PARADISE AIRPORT
Days Above Standard 1-Hour 8-Hour
Year 1-Hour State 1-Hour Nat’l 8-Hour Nat’l Maximum Maximum
2003 5 0 8 0.101 0.091
2002 9 0 13 0.112 0.101
2001 3 0 6 0.101 0.089
Notes:
All concentrations express in parts per million (ppm)
State Ambient Air Quality Standard 1-Hour Ozone is 0.09 ppm
National Ambient Air Quality Standard 1-Hour Ozone is 0.12 ppm
National Ambient Air Quality Standard 8-Hour Ozone is 0.08 ppm
Blanks mean that there was insufficient data available to determine the value
TABLE 15.10A
PM10 TRENDS SUMMARY: BUTTE COUNTY-CHICO-MANZANITA AVENUE
Estimated Days Above Standard Annual 3-Year High 24-hr.
Year State Nat’l Average Average Average
2003 5.8 0 21.7 30 54
2002 36.5 0 28.8 30 96
2001 30 0 29.9 31 112
TABLE 15.10B
PM10 TRENDS SUMMARY: BUTTE COUNTY – PARADISE-FIRE STATION #1
Estimated Days Above Standard Annual 3-Year High 24-hr.
Year State Nat’l Average Average Average
2003 0 42
2002 0 48
2001 0 37
Notes:
All concentrations expressed as micrograms per cubic meter (ug/m3)
Estimated Days Above Standard is the estimated number of days in the year that the California and national 24-hour PM10 standards would have
been exceeded had sampling occurred every day of the year. Sampling typically occurs once every 6 days.
State Ambient Air Quality Standard for PM10 24-hour average is 50 ug/m3, annual average is 20 ug/m3
Annual and 3-Year averages are based on State statistics for California approved samplers.
National ambient air quality standard for PM10 24-hour average is 150 ug/m3, annual average is 50 ug/m3
Blanks mean that there was insufficient data available to determine the value.