EPA-453/R-94-066-A
STUDY OF
VOLATILE ORGANIC COMPOUND EMISSIONS
FROM
CONSUMER AND COMMERCIAL PRODUCTS
REPORT TO CONGRESS
March 1995
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ACKNOWLEDGEMENT
The Study of VOC Emissions from Consumer and Commercial Products was
completed with a great degree of cooperation and assistance from the Chemical Specialties
Manufacturers Association, the Cosmetic, Toiletry, and Fragrance Association, the Soap and
Detergent Association, the Automotive Chemical Manufacturers Council, the National
Aerosol Association, and the Adhesive and Sealant Council.
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TABLE OF CONTENTS
Executive Summary ix
1. Introduction 1-1
Background 1-1
Requirements of §183(e) - Consumer and Commercial Products 1-2
Scope of Consumer and Commercial Products under §183(e) 1-3
EPA's Consumer and Commercial Products Study 1-3
References 1-5
2. Findings of the Consumer and Commercial Products Study 2-1
Summary of Findings 2-1
Scope of Products Subject to §183(e) 2-3
Role of Consumer and Commercial Products in Ozone Nonattainment 2-4
Control Measures and Systems of Regulation under §183(e) 2-10
Regulatory Environment Surrounding Consumer Products 2-15
Special Considerations Concerning Consumer Products 2-17
References 2-18
3. Photochemical Reactivity 3-1
The Chemistry of "Reactivity" 3-1
The Measurement of Reactivity 3-3
Reactivity Scales 3-5
Approaches to Developing Reactivity-Based Control Strategies 3-5
Meeting the Requirements of §183(e) 3-6
References . 3-10
4. Criteria for Regulating Products under §183(e) 4-1
Introduction 4-1
Factor 1: Uses, Benefits, and Commercial Demand 4-1
Factor 2: Health or Safety Functions 4-5
Factor 3: Products Which Emit Highly Reactive Compounds 4-6
Factor 4: Availability of Alternatives 4-8
Factor 5: Cost-Effectiveness of Controls 4-9
Additional Considerations 4-11
Use of the Criteria to Develop the Schedule for Regulations 4-12
References 4-13
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TABLE OF CONTENTS (Continued)
5. Comprehensive Emissions Inventory 5-1
Elements of the Inventory 5-1
Adjustments to Inventory Data 5-2
Consumer Products Survey 5-3
Industrial Products Affected by Existing Federal Programs 5-28
Products Addressed by Special Studies 5-43
References 5-55
6. Fate of Consumer Product VOC in Landfills and Wastewater 6-1
Fate of Consumer Product VOC in Landfills 6-1
Fate of Consumer Product VOC in Wastewater 6-9
References 6-20
7. Economic Incentives to Reduce VOC Emissions from Consumer
and Commercial Products 7-1
8. Aerosol Products and Packaging Systems 8-1
Aerosol Consumer Products as Sources of VOC Emissions 8-1
Aerosol System Components 8-2
Industry Profile 8-8
Alternative Dispensing Technologies 8-10
References 8-15
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LIST OF FIGURES AND TABLES
Figure 6-1 Potential Pathways for VOC in Consumer Product Residuals
Placed in Municipal Landfills
Table 2-1 VOC Emissions from Consumer and Commercial Products in
Ozone Nonattainment Areas (1990)
Table 2-2 Sources of VOC Emissions in 1990 (Nationwide)
Table 2-3 Estimated Emission Reductions from Consumer Products
Table 4-1 Summary of Factors and Criteria
Table 4-2 Classes of Highly Reactive Compounds
Table 5-1 Results of the Consumer Products Survey
Table 5-2 VOC Emissions in Nonattainment Areas for Products
Affected by Existing Federal Programs
Table 5-3 VOC Emissions in Nonattainment Areas for Products
Covered by Special Studies
Table 6-1 Ultimate Fate of VOC and VOC Groups (in Landfills)
Table 6-2 Potential for Consumer Products to Enter Wastewater
Table 6-3 Volatility of Consumer Product VOC in Water
Table 6-4 Summary of the Models Identified
Table 6-5 Fate of Selected Consumer Product VOC in Wastewater
Table 7-1 Summary of Fee Program Design Options
Table 7-2 Summary of Permit Program Design Options
Table 7-3 Comparison of Economic Incentives and Hypothetical VOC
Content Standards When the Environmental Goal is
a Fixed Quantity of Emissions
Table 8-1 U.S. Aerosol Products Filled in 1989
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EXECUTIVE SUMMARY
The purpose of this report is to respond to the Clean Air Act (Act) requirement to
report to the Congress on consumer and commercial products as contributors to ozone
nonattainment. The report is primarily technical in nature and does not conclude which
products may warrant federal regulation. Such decisions will be addressed when EPA
publishes a regulatory schedule. The requirements of the Act concerning consumer and
commercial products are discussed below.
Section 183(e) of the 1990 Amendments to the Act requires the EPA to conduct a
study of emissions of volatile organic compounds (VOC) into the ambient air from consumer
and commercial products. As stated in §183(e), the objectives of the study are (1) to
determine the potential of consumer and commercial product VOC emissions to contribute to
ozone levels which violate the national ambient air quality standard (NAAQS) for ozone; and
(2) to establish criteria for regulating consumer and commercial products or classes or
categories of products under the authority of §183(e) of the Act. The EPA is required to
submit a report to Congress that documents the results of the study.
Upon submission of the report, the EPA is required to list those categories of products
that are determined, based on the study, to account for at least 80 percent of the total VOC
emissions, on a reactivity-adjusted basis, from consumer and commercial products in areas
that violate the NAAQS for ozone. The EPA is required to divide the list into 4 groups to
establish priorities for regulation. Beginning no later than 2 years following publication of
the list and regulatory schedule, the EPA is required to regulate one group every two years
until all 4 groups are regulated.
Although §183(e) addresses VOC emissions from "the use, consumption, storage,
disposal, destruction, or decomposition" of consumer and commercial products, the EPA
does not intend to regulate the users of the products. Furthermore, in developing regulations
under §183(e), the EPA will duly consider the impacts of such rules on product performance
and cost to the consumer, and will strive to minimize any adverse impacts of such
regulations. In developing specific regulations, the EPA will evaluate new information on
cost-effectiveness as well as other criteria and may, in the process, reassess the product
listing and schedule.
In establishing criteria for regulating consumer and commercial products, §183(e)
requires consideration of factors which are broader than the EPA usually considers in
developing regulations. Under §183(e), the EPA is required to take into consideration
(1) the uses, benefits, and commercial demand of consumer and commercial products;
(2) any health or safety functions served by the products; (3) those consumer and commercial
products that emit highly reactive VOC into the ambient air; (4) those products that are
subject to the most cost-effective controls; and (5) the availability of any alternatives to such
consumer and commercial products that are of comparable costs, considering health, safety,
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and environmental impacts. The EPA believes that consideration of these factors will ensure
that consumer needs and demands continue to be met.
Within a short time after submitting this report to Congress, the EPA will publish in
the Federal Register a schedule for regulation of products under §183(e). The initial
publication of the list and schedule for regulations will not be considered final Agency
action. Accordingly, the four groups may be modified such that a product category may be
moved to a different group, delisted altogether, or added to the list. The EPA will make
appropriate adjustments to ensure that it continues to meet the statutory requirements of
§183(e) to regulate categories which account for at least 80 percent of baseline emissions.
Should a product be listed for regulation, the extent to which the product is affected
will be determined at the time of rulemalting. As part of the rulemaking process, the EPA
will consider public comments at the time each product is considered for regulation.
The persistence of the ground-level ozone problem has caused State and local air
pollution agencies to seek emission reductions beyond those which have been obtained
through regulation of the conventional mobile and stationary sources of emissions. As a
result, several agencies are adopting rules to regulate various household consumer products.
Individual State and local regulations for consumer products could have significantly different
requirements, which in turn could lead to serious disruption of the national distribution
network for consumer products. In response, the consumer products industry has urged EPA
to issue national rules for consumer products to provide consistency across the country. The
States are also supportive of a national rule which will assist them in their efforts toward
achievement of ozone attainment.
In response to these concerns, EPA consulted with consumer product manufacturers
and other interested parties to determine which products would be the most amenable to an
expedited regulation that could achieve significant VOC emission reductions without serious
adverse effects on consumer satisfaction or price of the products. The industry identified a
group of 24 consumer products that meet these criteria (see section 2.6). Both the consumer
products industry and the States strongly support expedited Federal regulation of these 24
product categories. The EPA plans to promulgate the rule for these 24 categories by early
1996.
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CHAPTER 1
INTRODUCTION
1.1 BACKGROUND
Ground-level ozone has been a pervasive pollution problem in the United States for several
decades. In the upper atmosphere, or stratosphere, ozone occurs naturally and forms a
protective layer to shield us from the sun's harmful ultraviolet rays. However, in the lower
atmosphere, or at "ground level,* man-made ozone can cause a variety of problems to human
health, crops and trees. It is this ground-level ozone problem that is the focus of this report.
Ground-level ozone can cause a wide range of health effects depending upon the ozone
concentration, the duration of exposure, and the activity level of the individual while exposed.
Scientific evidence indicates that ambient levels of ozone affect people with impaired respiratory
systems, such as asthmatics, as well as healthy, active adults and children. For example,
increased ozone levels can aggravate preexisting respiratory disease, as observed in studies
associating increased ozone levels with increased hospital admissions and emergency department
visits for respiratory causes. In healthy adults and children, exposure to ozone for six to eight
hours at moderate levels of exertion and at relatively low concentrations has been found to
reduce lung function. Similar reductions in lung function result from one to three hours of
exposure at heavy levels of exertion at higher concentrations. In adults these decreases in lung
function are often accompanied by symptoms such as cough, chest pain, and shortness of breath,
with the severity of the symptoms increasing with increasing ozone concentration. In addition,
animal studies showing structural damage in the lung after months of exposure to ozone raise
concerns about potential chronic effects, although attempts to associate chronic health effects in
humans with long-term ozone exposure have yet to provide unequivocal evidence that such a
linkage exists.
Each year ground-level ozone is also responsible for agricultural crop yield loss. This loss
has been estimated to be in the range of several billion dollars annually, although the assessment
of economic effects on the agricultural sector remains incomplete. Ozone also causes noticeable
foliar damage in many crops and species of trees. Studies also indicate that current ambient
levels of ozone are responsible for damage to forests and ecosystems.
Ground-level ozone is particularly difficult to control because it is not emitted directly into
the atmosphere, but instead is formed by a complex photochemical reaction caused by primarily
by volatile organic compounds (VOC), nitrogen oxides (NOX), heat and sunlight. VOC are
emitted from a variety of sources, including automobile exhaust, industrial and chemical
processes, evaporating gasoline vapors, and many kinds of consumer and commercial products.
NOX is emitted from the combustion of fuels from sources like automobiles, power plants and
industrial boilers.
Since the early 1970's the U.S. Environmental Protection Agency (EPA) and State and
local air pollution control agencies have had programs in place to protect the public from
ground-level ozone. Traditionally these programs have focused on reducing emissions from
motor vehicles and a variety of industrial and chemical processes. As a result, major
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improvements have occurred from these kinds of sources. However, substantial increases in
vehicles miles travelled and other growth factors have made ground-level ozone much more
difficult to control than initially anticipated.
By 1990 there were 98 areas in the country that did not meet the EPA-established national
ambient air quality standard (NAAQS) for ozone. Approximately ISO million Americans lived
in these areas. That same year the Congress passed and President Bush signed into law
sweeping amendments to the Clean Air Act (Act). The 1990 Amendments required a broad
array of programs to further reduce emissions of VOC, NOX and/or other pollutants from the
automobile, petroleum, chemical, steel, utility, and pulp and paper industries, as well as a wide
variety of other large and small sources.
In the 1990 Amendments, the Congress also required for the first time that EPA study and
regulate emissions from consumer and commercial products. In putting these requirements into
place, Congress recognized that national, state and local emission control programs traditionally
focused on emissions from mobile (e.g. cars) and stationary (e.g. factories) sources. Although
those control programs can be effective, Congress was concerned that ozone control programs
were generally ignoring major components of the VOC emissions inventory which could also
be effectively controlled.
In part, the Congressionally mandated program to focus on consumer and commercial
products was based on a 1989 report by the Congressional Office of Technology Assessment
(OTA) entitled Catching our Breath: Next Steps for Reducing Urban Ozone*. The report
indicated that individually small, diverse sources of VOC (so-called "area sources") contribute
significantly to the continuing ozone nonattainment problem. According to the OTA report, a
major source of VOC emissions is the wide range of consumer and commercial products.
Many sectors of industry have been supportive of the requirements contained in the 1990
Amendments to establish a national program to control emissions from consumer and
commercial products and other area sources. Some in industry were concerned that, unless EPA
looked at the consumer and commercial product sector of the inventory, ozone control programs
would have to continue to require increasingly expensive emission reductions from traditional
mobile and stationary sources. Consumer and commercial products, by comparison, may
represent an opportunity for much more cost-effective control. Faced with a broad array of
varying State regulations controlling VOC emissions from their products, several companies that
manufacture consumer and commercial products have also supported national regulations to help
encourage national consistency.
1.2 REQUIREMENTS OF §183(e) - CONSUMER AND COMMERCIAL PRODUCTS
Although control of one small source of VOC emissions may contribute little to overall
ambient air quality, VOC reductions obtained through regulation of multiple small sources could
have a beneficial additive effect. Section 183(e) of the 1990 Amendments requires the EPA to
conduct a study of emissions of VOC into the ambient air from consumer and commercial
products. The objectives of the study are (1) to determine the potential of consumer and
commercial product VOC emissions to contribute to ozone levels which violate the NAAQS for
ozone; and (2) to establish criteria for regulating consumer and commercial products or classes
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or categories of products under the authority of §183(e) of the Act. In establishing criteria for
regulating consumer and commercial products, the EPA must take into consideration (1) the
uses, benefits, and commercial demand of consumer and commercial products; (2) any health
or safety functions served by the products; (3) those consumer and commercial products that
emit highly reactive VOC into the ambient air; (4) those products that are subject to the most
cost-effective controls; and (5) the availability of any alternatives to such consumer and
commercial products that are of comparable costs, considering health, safety, and environmental
impacts. Upon completion of the study, the EPA must submit a report to Congress that
documents the results of the study.
The EPA must also list those categories of products that are determined, based on the
study, to account for at least 80 percent of the total VOC emissions, on a reactivity-adjusted
basis, from consumer and commercial products in areas that violate the NAAQS for ozone. The
EPA must divide the list into 4 groups to establish priorities for regulation. Beginning no later
than 2 years following publication of the list, the EPA must regulate one group every two years
until all 4 groups are regulated.
1.3 SCOPE OF CONSUMER AND COMMERCIAL PRODUCTS UNDER §183(e)
According to §183(e), "the term 'consumer or commercial product' means any substance,
product (including paints, coatings, and solvents), or article (including any container or
packaging) held by any person, the use, consumption, storage, disposal, destruction, or
decomposition of which may result in the release of volatile organic compounds. The term does
not include fuels or fuel additives regulated under section 211, or motor vehicles, non-road
vehicles, and non-road engines as defined under section 216."
The EPA believes that the statutory definition of consumer or commercial product is much
broader than just the traditional "consumer" products (e.g., personal care products, household
cleaning products, household pesticides, etc.). Instead, consumer and commercial products
include all VOC-emitting products used in homes, businesses, institutions, and a multitude of
commercial manufacturing operations. Among these products are a wide range of surface
coatings, metal cleaning solvents, graphic arts inks, adhesives, asphalt paving materials, and
many other products used in manufacturing processes or commercial operations, many of which
have been previously regulated by the EPA and/or by the States.
Throughout this document, "consumer products" refers to those products used in and
around the home, office, institution, or similar settings. The commercial and institutional use
of these or similar products is also included under "consumer products." For example, a floor
wax applied to the floor of the cafeteria of a factory would be considered a consumer product.
The term "commercial products," on the other hand, generally refers to products used in
manufacturing operations or in other commercial activities such as garment drycleaning,
publication printing, and roadway paving. A more thorough discussion of the scope of §183(e)
is presented in Section 2.2. Categories of consumer and commercial products and estimates of
their VOC emissions are presented in Section 2.3 and in Chapter 5.
1.4 EPA'S CONSUMER AND COMMERCIAL PRODUCTS STUDY
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The primary objectives of the study and report to Congress are to educate the EPA and
Congress on consumer and commercial products as contributors to ozone nonattainment, to
identify opportunities for reduction of VOC emissions from the use of these products, to
establish criteria for regulation of consumer and commercial products, and to provide
information which can be used in conjunction with the criteria to list and schedule categories for
regulation.
1.4.1 Organization of the Consumer and Commercial Products Study
The consumer and commercial product study was a comprehensive, integrated effort
directed toward meeting the objectives listed above and in §183(e)(2)(A). This Report to
Congress presents an overview of the findings of the individual studies carried out by the EPA.
Volumes which comprise the consumer and commercial products study are:
(EPA-453/R-94-066-a) Report to Congress
(EPA-453/R-94-066-b) Comprehensive Emissions Inventory
(EPA-453/R-94-066-C) Fate of Consumer Product VOC in Landfills
(EPA-453/R-94-066-d) Fate of Consumer Product VOC in Wastewater
(EPA-453/R-94-066-e) Economic Incentives to Reduce VOC Emissions from Consumer
and Commercial Products
(EPA-453/R-94-066-0 Aerosol Products and Packaging Systems
1.4.2 Contents of the Report to Congress
This Report to Congress contains eight chapters, including this introduction. Chapter 2
presents a summary of findings of the EPA's study of consumer and commercial products and
addresses such topics as (1) scope of products covered by §183(e); (2) emission estimates for
all categories of products subject to §183(e); (3) the role of consumer and commercial products
in the ozone nonattainment problem; (4) control measures and systems of regulation available
under §183(e); (5) the regulatory environment surrounding consumer products; and (6)
opportunities for emission reductions from regulation of specific categories of consumer
products.
Chapter 3 addresses the issue of relative photochemical reactivity as it relates to consumer
and commercial products and includes (1) a description of the reactivity-related requirements of
§183(e); (2) a discussion of the science of photochemical reactivity; (3) an explanation of the
role of relative reactivity in developing ideal ozone control strategies; and (4) methodologies
which could be used now, based on the current uncertainties and limitations associated with
reactivity, to fulfill the requirements of §183(e).
Chapter 4 presents a detailed discussion of the criteria developed by the EPA for
regulating consumer and commercial products under §183(e), describes how the criteria are
being used, and lists the considerations on which the EPA will base the selection of categories
for regulation.
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Chapter 5 through 8 present in-depth summaries of each of the supporting volumes of the
consumer and commercial products study. Virtually all the substantive information contained
in the five volumes is presented in these summaries. They address the comprehensive emissions
inventory (Chapter 5); the fate of VOC in consumer products which are disposed of in landfills
or enter the wastewater stream (i.e., are the VOC emitted to the air, or are they changed or
otherwise kept from being emitted through some physical or chemical process?). (Chapter 6);
economic incentive programs which could be used to reduce VOC emissions from consumer and
commercial products (Chapter 7); and aerosol products and packaging systems (Chapter 8).
1.5 REFERENCES
1. U.S. Congress, Office of Technology Assessment, Catching our Breath: Next Steps for
Reducing Urban Ozone, OTA-O-412, Government Printing Office, Washington, D.C.,
July 1989.
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CHAPTER 2
FINDINGS OF THE CONSUMER AND COMMERCIAL PRODUCTS STUDY
This chapter presents the findings of the EPA's 4-year, comprehensive study of consumer
and commercial products. The objectives of this chapter are to (1) present a concise synopsis
of the EPA's findings; (2) give the reader an appreciation of the breadth of products considered
to be consumer and commercial products; (3) explain the role consumer and commercial
products play in the nation's ozone nonattainment problem; (4) list the control measures and
systems of regulation authorized under §183(e) to control VOC emissions from these products;
(5) describe the current regulatory environment surrounding consumer products; and (6) identify
opportunities for VOC reductions which could be obtained through federal regulation of specific
categories of consumer products.
2.1 SUMMARY OF FINDINGS
A summary of the EPA's findings is presented below. Each of these findings is supported
by the EPA's study of consumer and commercial products. The findings are keyed to other
sections of this report to Congress as indicated by numbers appearing at the end of each entry.
• Failure to meet the national health standard for ozone is a persistent problem. Ozone is
the least understood of the criteria pollutants and is the most intractable to date. Although
some progress has been made through past regulatory efforts, large areas of the country
continue to exceed the health-based national ambient air quality standard (NAAQS) for
ozone. The extent and complexity of the ozone nonattainment problem has caused
attention to be turned toward emission sources beyond the conventional stationary and
mobile sources. In addition, such circumstances have led the EPA to consider innovative
approaches such as seasonal and market-based strategies to obtain emission reductions.
(1.1,2.2)
• To be the most effective, ozone control strategies ideally should be based not only on mass
VOC and NOX emissions but should consider the relative photochemical reactivity of
individual species, the VOC-to-NO, ratios prevalent in specific airsheds, and other factors
which could work together to minimize the formation of ozone with minimum adverse
impacts. Reactivity data on VOC, especially those compounds used to formulate
consumer and commercial products, is extremely limited. Better data, which can be
obtained only at great expense, is needed if the EPA is to consider relative photochemical
reactivity in any VOC control strategy. In the meantime, a practical approach is to act
on the basis of mass VOC emissions. (3.0)
• Consumer and commercial products, while individually small sources of VOC emissions,
contribute significantly to the ozone nonattainment problem. In 1990, consumer and
commercial products emitted approximately 3.3 million tons of VOC hi ozone
nonattainment areas, or about 6 million tons of VOC nationwide. This is approximately
28 percent of all man-made VOC. (2.3, 5.0)
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• The scope of consumer and commercial products subject to §183(e) is very broad and
includes not only household consumer products but many products used commercially and
in industrial manufacturing operations. This vast universe of products ranges from
underarm antiperspirants and deodorants to coatings used in the manufacture of
automobiles. (1.2, 2.2)
• Partially spent consumer products which are disposed of in landfills eventually release
then- residual VOC content. Unless the particular landfill has emission controls applied,
this VOC ultimately enters the ambient air. The EPA was unable to determine what the
extent to which consumer products are disposed of in landfills with controls in place.
Consequently, no adjustment to emission estimates could be made for fate of consumer
product VOC in landfills. (6.1)
• In many cases, VOC contained in consumer products enter the waste water stream and are,
to varying extents, biodegraded instead of being emitted to the ambient air. For example,
ethanol is almost completely biodegraded, while Stoddard solvent undergoes no
biodegradation and is emitted to the air. (6.2)
• Opportunities for emission reductions do exist. With regard to consumer products,
California and other States have issued regulations which limit the VOC content of
approximately two dozen categories of products. These regulations were developed over
several years with extensive interaction with the consumer products industry. The EPA
has estimated that the VOC content limitations imposed by the California regulations, if
applied nationwide, may result in an overall VOC reduction of approximately 25 percent
from the 1990 baseline for those categories. (2.6)
• In developing control measures for consumer products, emission reductions must be
balanced with product efficacy, consumer acceptance, and consideration of which products
are subject to the most cost-effective controls. Reformulation of consumer products may
require lead time and expense for research, product development, testing, and regulatory
agency approval (Food and Drug Administration, Department of Transportation, Federal
Trade Commission, etc.) ~ all of which add to the cost of compliance. Accordingly, the
EPA recognizes these requirements and will duly consider them at the time of rulemaking.
(2.4)
• Consumer education will be essential to successful implementation of control measures for
many consumer and commercial products. Education can be employed alone or in
combination with other control measures. (2.4)
• Economic incentive programs appear to be viable alternatives to command and control
strategies to reduce VOC emissions from consumer and commercial products. Optimal
selection of an economic incentive regulatory strategy depends upon the objectives of the
program. Certainty of emission reductions, minimisation of control and/or implementation
costs, technological innovation, and flexibility afforded by the program are all objectives
which must be considered in selecting a strategy. Tradeoffs are intrinsic to regulatory-
policy design. Consequently, the best regulatory strategy for consumer and commercial
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products depends upon the particular universe of products being regulated and the priority
of objectives. (2.4, 7.0)
• A widely held misconception is that most aerosol products employ chlorofluorocarbons
(CFC's) as propellants and contribute to stratospheric ozone depletion. In 1978, the EPA
banned the use of CFC's in virtually all aerosol products, the exceptions being medical
products, military specification products, and aviation products. Hydrocarbons (propane,
butane, and isobutane), which are VOC, are currently the predominant propellant
compounds. (8.2)
• Aerosol products function as systems composed of the product, the propellant, the valve,
and the container. Hydrocarbon propellants not only expel the product from the container
but serve as diluents in the product formulation. Consequently, seemingly expeditious
measures to reduce VOC content (e.g., changing from an aerosol to a pump spray,
switching to a non-VOC compressed gas propellant, etc.) may not achieve the desired
VOC reduction. (8.2)
2.2 SCOPE OF PRODUCTS SUBJECT TO §183(e)
In order to comply with the requirements of §183(e), the EPA identified the range of
consumer and commercial products to address in the study. Section 183(e) defines "consumer
or commercial product" to mean "any substance, product (including paints, coatings, and
solvents), or article (including any container or packaging) held by any person, the use,
consumption, storage, disposal, destruction, or decomposition of which may result in the release
of volatile organic compounds. The term does not include fuels or fuel additives regulated under
section 211, or motor vehicles, non-road vehicles, and non-road engines as defined under section
216."
Initially, the EPA considered a narrow interpretation of the statutory definition. According
to this interpretation, only household consumer products, including commercial and institutional
uses, would be addressed by the study under §183(e). These are the products that are
considered by the general public to be "consumer products." They include personal care
products, household cleaning products, household pesticides, aerosol spray paints, and other
products used in or around homes, offices, schools, etc. Products used in industrial
manufacturing operations were not included.
However, the statutory definition and legislative history of the 1990 Amendments indicate
that a broader interpretation is warranted. Thus, the EPA currently interprets "consumer or
commercial product" to include all VOC-emitting products used in homes, businesses,
institutions, and a wide range of industrial manufacturing operations. In addition to "consumer
products," the scope of §183(e) includes many "commercial products." These products are
generally not used in or around the home, office, or institution, but in industrial applications
such as metal degreasing, garment dry cleaning, publication printing, roadway paving,
shipbuilding and repair, and the manufacture of numerous products including automobiles,
fiberglass boats, fabric, large appliances, wood furniture, and many others.
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Given the breadth of the statutory definition, there is a need for a clear understanding of
what is meant by ". . substance, product . . or article . ."for purposes of identifying target
entities for developing emission estimates and for listing categories for regulation. This
interpretation is complicated by the fact that products are manufactured using other products and
substances. For example, the manufacture of automobiles (products), involves the use of
coatings (products). These coatings are manufactured using pigments, resins, solvents, and other
ingredients (products). In order to avoid duplicate counting and redundant regulation of
consumer and commercial products, only one stage in this process should be associated with the
term "product" under §183(e).
In establishing boundaries for the meaning of "product," a key question is, "where along
the chain of predecessor products and substances should one go to establish a target entity for
regulation under §183(e)?" The following characteristics were developed to aid in identifying
consumer and commercial "products" to be included in the scope of §183(e):
• The "product" must be an entity which has definition and is clearly identifiable with
regard to the specific function(s) it performs.
• The "product" must be identified in such a manner that it is distinguishable from other
products for the purpose of applying the criteria developed pursuant to §183(e).
Specifically, a product must be able to be compared with other products with regard to
uses, benefits, commercial demand, health and safety functions, nature and magnitude of
emissions, cost-effectiveness of controls, and availability of alternative products.
• The "product" must be capable of being evaluated such that a determination of "best
available controls" can be made, in the event the product is targeted for regulation.
• The "product" must not be an ingredient of another formulated product. However, a
"product" can be something used in the manufacture of an article not considered a
"product" under §183(e). For example, a solvent used in the formulation of paint should
not be considered a "product," but the paint, when applied to an automobile [not itself a
product under §183(e)], should be a "product" within the scope of §183(e).
2.3 ROLE OF CONSUMER AND COMMERCIAL PRODUCTS IN THE OZONE
NONATTAINMENT PROBLEM
As stated in §183(e)(2)(A)(i), one of the objectives of the consumer and commercial
products study was to "determine their potential to contribute to ozone levels which violate the
national ambient air quality standard for ozone." The purpose of this section is to examine how
these products collectively contribute to the ozone nonattainment problem. This relationship is
dependent on (1) the mass VOC emissions from consumer and commercial products; (2) the
relative share of all VOC emissions which can be attributed to these products; and (3) how
individual species of VOC emitted from these products participate in the photochemical reactions
which result in ozone formation. Each of these topics is discussed below, followed by the
EPA's conclusions regarding the role of consumer and commercial products in ozone
nonattainment.
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2.3.1 Emission Estimates
A major component of the study was development of a comprehensive inventory of
emissions from consumer and commercial products. The inventory study is summarized in
Chapter 5. The EPA found that VOC emissions from consumer and commercial products in
ozone nonattainment areas totalled approximately 3.3 million tons in 1990. Table 2-1 presents
emission estimates for the principal categories of consumer and commercial products.
TABLE 2-1
VOC EMISSIONS FROM CONSUMER/COMMERCIAL PRODUCTS
IN OZONE NONATTAINMENT AREAS (1990)
Product Category
"Consumer Products" (EPA Survey)
Personal care products
Household products
Automotive aftermarket products
Adhesives and sealants
FIFRA products (pesticides, etc.)
Coatings & related (except AIM)
Remaining products surveyed
174,115
55,095
106,469
45,467
121,464
89,405
5,194
Architect & Indust Maint (AIM) Coatings
Commercial Adhesives
Tire manufacturing cements
Platen adhesives (textile industry)
Miscellaneous industrial adhesives
26,400
2,092
201,600
Commercial Solvents
Metal cleaning (degreasing) solvents
Industrial cleaning (cleanup) solvents
36,000
150,000
Emissions
Nonattainment
Areas (tons/yr)
597,209
315,000
230,092
290,323
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Product Category
Petroleum drycleaning solvents
Synthetic fiber spinning solvents
Textile industry equipment cleaning
Textile industry spot cleaners
Automotive repair - parts washers
54,600
46,200
68
848
2,607
Commercial Coating Operations
Autobody refinishing
Aerospace coatings
Wood furniture manufacture
Ship building and repair
Metal furniture coating
Flat wood paneling coating
Large appliance coating
Magnet wire coating
Metal can coating
Metal coil coating
Miscellaneous metal product coating
Auto and light truck assembly
Paper, film, and foil coating
Magnetic tape coating
Auto & business machine plastic parts
Flexible package printing
Rotogravure publication printing
Lithographic printing
Letterpress printing
Fabric coating
55,000
107,500
60,000
15,100
63,000
20,000
15,600
4,800
45,000
21,600
218,400
75,000
65,000
5,500
22,000
150,000
20,000
600,000
28,200
21,000
Emissions
Nonattainment
Areas (tons/yr)
1,713,300
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TABLE 2-1 (Continued)
VOC EMISSIONS FROM CONSUMER/COMMERCIAL PRODUCTS
IN OZONE NONATTAINMENT AREAS
Product Category
Fabric printing
Mold release agents
25,200
75,400
Commercial Paving and Roofing
Cutback asphalt paving materials
Asphalt concrete paving materials
Roofing - built-up
Roofing - elastomeric
Roofing - modified bitumen
128,400
360
7,126
9,123
2,276
Other Products and Activities
Fiberglass boat manufacturing
Kerosene space heaters
Camp stoves and lanterns
Artificial fireplace logs
Agricultural pesticide application
Commercial explosives
12,100
39
6
154
15,000
2,422
TOTAL FOR ALL §183(e) CATEGORIES
Emissions
Nonattainment
Areas (tons/yr)
147,285
29,721
3,322,930
2.3.2 Consumer and Commercial Product Emissions in Perspective
In order to assess the extent to which consumer and commercial products contribute to
ozone nonattainment, the VOC contribution of these products must be put into perspective
relative to all man-made sources of VOC emissions. Based on the results of the inventory study,
VOC emissions from consumer and commercial products in 1990 were estimated to be 3.6
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million tons in ozone nonattainment areas, or about 6 million tons nationwide. This is
approximately 28 percent of all man-made VOC emissions. The principal source categories and
their mass VOC emissions are presented in Table 2-2.
TABLE 2-2
SOURCES OF VOC EMISSIONS IN 1990 (NATIONWIDE)
Emission
Source Category
Mobile Sources (Automobiles, etc.)
Consumer/Commercial Products
Petroleum Marketing
Fuel Combustion (Stationary Sources)
Forest, Agricultural, and Other Burning
Petroleum Refineries
Organic Chemicals Manufacturing
Industrial Manufacturing
TOTAL FOR ALL SOURCES
Nationwide
Emissions (tons/yr)
7,920,000
6,000,000
2,460,000
2,300,000
990,000
820,000
550,000
400,000
21,440,000
Share of Total
(percent)
36.9
28.0
11.5
10.7
4.6
3.8
2.6
1.9
100.0
2.3.3 Potential of Consumer and Commercial Products to Contribute to Ozone Nonattainment
»
Although magnitude of mass VOC emissions is an important consideration, the EPA
acknowledges that, ideally, a rigorous determination of the potential of consumer and
commercial products to contribute to ozone nonattainment should also consider the propensity
of individual ingredients to react photochemically with NO, in the atmosphere to form ozone.
Two possible methods of accounting for photochemical reactivity in making this determination
are presented below.
2.3.3.1 Reactivity Scale Method
The potential to contribute to ozone nonattainment could be expressed as the amount of
ozone formed by VOC emitted from consumer and commercial products relative to the ozone
formed by the VOC otherwise present (i.e., how the ambient ozone concentration is affected by
addition of VOC from consumer and commercial products). Using the reactivity scale method,
this relationship can be expressed mathematically as:
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Y CCP(VOG)T.
CCP Ozone Potential = ^ (1)
"
where CCP(VOC)j and T, are the weight-fraction and reactivity, respectively, of consumer and
commercial product VOC species i, and AMB(VOC)j and TJ are the weight-fraction and
reactivity, respectively, of ambient VOC species j. The reactivity factors Tt and r} refer to the
ozone yield (i.e., the amount of ozone produced per amount of VOC present).
The reactivity scale method is simple but requires that reactivity data exist for every VOC
species emitted from consumer and commercial products. Consumer and commercial product
VOC emissions, unlike mobile source (automotive) emissions, generally have not been the
subject of atmospheric studies. Consequently, existing reactivity data on these compounds are
either largely incomplete or uncertain. The method also suffers from uncertainties, mainly in
the reactivity data themselves — the reactivity chemistry for most of these species is not well
known ~ and in the linearity assumption used in equation (1). Overall, the reactivity scale
method, even with adequate data on reactivity, should be viewed as providing only approximate
results.2
2.3.3.2 Air Quality Simulation Model Method
The potential of consumer and commercial products to contribute to ozone
nonattainment can also be estimated through air quality simulation model (AQSM) computations
of ozone formed in the presence, and in the absence, of the consumer and commercial product
VOC, for any set of ambient conditions. Such estimates are clearly more reliable and useful
than those derived by the reactivity scale approach presented above. However, they, also, are
not without significant uncertainties, and are extremely costly to obtain. Uncertainties lie in the
chemistry, dispersion, and emissions components of, or inputs to, the models. To reduce such
uncertainties requires costly research, efforts to obtain reliable and complete input data, and
field-testing of the models. Finally, for universal use, estimates of these products' potential to
contribute to nonattainment should be based on model computations for several "representative"
ozone nonattainment urban atmospheres.2
2.3.4 EPA's Conclusions Regarding the Role of Consumer and Commercial Products
Because of the uncertainties, inconsistencies, and lack of reactivity data on individual
compounds, the EPA concluded that a rigorous determination of the potential of consumer and
commercial products to contribute to ozone nonattainment is not possible at this time. In order
to fulfill the requirements of the Act, the EPA was forced to make the determination that since
consumer and commercial products collectively account for approximately 28 percent of all man-
made VOC emissions, they contribute significantly to ozone formation in nonattainment areas.
This approach, while not a robust evaluation of the causal relationship between consumer
and commercial product emissions and ozone nonattainment, represents the EPA's best effort,
given the uncertainties and inconsistencies of reactivity, to determine the role of consumer and
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commercial products in ozone nonattainment. If, in the future, sufficient information or new
methodologies become available, the EPA may reevaluate this finding.
2.4 CONTROL MEASURES AND SYSTEMS OF REGULATION UNDER §183(e)
Section 183(e) presents specific control measures and systems of regulation to be used by
the EPA to reduce VOC emissions from consumer and commercial products. The term, control
measures, refers to techniques which are applied to products and/or processes to prevent or
reduce emissions. Systems of regulation are various mechanisms by which the appropriate
control measures can be implemented. The following sections describe the control measures
available to the EPA in regulating consumer and commercial products, the systems of regulation
which may be employed to implement these measures, and who may be subject to the
regulations.
2.4.1 General Constraints
2.4.1.1 Regulated Entities
Regulated entities are those persons on which regulations may be imposed in order to
implement the various control measures. Section 183(e)(l)(C) defines regulated entities to be
"(i) manufacturers, processors, wholesale distributors, or importers of consumer or commercial
products for sale or distribution in interstate commerce in the United States, or (ii)
manufacturers, processors, wholesale distributors, or importers that supply the entities listed
under clause (i) with such products for sale or distribution in interstate commerce in the United
States."
2.4.1.2 Best Available Controls
In regulating consumer and commercial products to reduce VOC emissions, the regulations
must require best available controls. Section 183(e)(l)(A) defines best available controls to be
"the degree of emissions reduction that the Administrator determines, on the basis of
technological and economic feasibility, health, environmental, and energy impacts, is achievable
through die application of the most effective equipment, measures, processes, methods, systems
or techniques, including chemical reformulation, product or feedstock substitution, repackaging
and directions for use, consumption, storage, or disposal."
2.4.1.3 Use of Control Techniques Guidelines
Under Section 183(e)(3)(C), the EPA may issue control techniques guidelines (CTGs) in
lieu of regulations where the Administrator determines that the CTGs will be substantially as
effective in reducing VOC emissions in nonattainment areas. In many cases, CTGs can be
effective regulatory approaches to reduce emissions of VOC in nonattainment areas — with the
advantage of not imposing control costs on attainment areas, where benefits of reducing VOC
emissions may be far less or zero. In the case of, for example, small volume consumer products
that are widely used (e.g., personal care products), a CTG might not be effective at reducing
VOC emissions because of difficulties in enforcement. However, for other cases (and for a
potentially large share of nonattainment area VOC emission sources), enforcement and
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compliance can effectively be focused at the source of the VOC emissions, be it the point of
manufacture, the point of end-use, or both. For example, VOC emissions from commercial
products used in industrial settings could be controlled effectively with a CTG that targeted
emissions at the point of end-use, as the population of end users is likely to be readily
identifiable.
2.4.2 Control Measures
Under §183(e), several control measures are available to EPA in reducing VOC emissions
from consumer and commercial products. Although specific measures are listed in the Act, the
EPA is not limited to those measures alone.
2.4.2.1 Reformulation
Reformulation of consumer and commercial products as a means of reducing VOC
emissions involves replacing one or more VOC ingredients with either non-VOC ingredients or
VOC ingredients of such low volatility that they have little propensity to enter the ambient au-
to react to form ozone. Replacement ingredients must be physically and chemically compatible
with the remainder of the formulation and must function in a manner similar to the original
constituent to maintain product integrity and efficacy. Ingredient interactions can complicate
reformulation efforts. For example, replacing a single compound can sometimes affect the
performance of other ingredients. Even the order in which ingredients are combined can affect
the efficacy of some formulations.
Reformulated products must undergo a series of tests before marketing can be considered.
The reformulation process begins by identifying appropriate replacement compounds (in this
case, non-VOC or low-volatility compounds). Alternative ingredients are tested for suitability
based on efficacy of the product, compatibility with other ingredients, shelf life and stability,
feasibility of mass production, and packaging needs. All of these tests, which are considered
essential for product development, are done by the formulator and are not required or monitored
by any regulatory agency.
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires pesticide
products to be registered with the EPA. Under FIFRA, a product is defined as a pesticide if
it is intended to prevent, destroy, repel, or mitigate any "pest," including any fungus, bacterium,
virus, or other microorganism found on inanimate surfaces. Consumer and commercial products
that claim to be antimicrobials (e.g., disinfectants, sterilants, etc.) are also considered to be
pesticides, and are therefore subject to FIFRA registration. Under FIFRA, formulators of
pesticides are required to demonstrate that the product does not cause "unreasonable adverse
effects on the environment." Reformulation of a FIFRA-registered product would therefore
require registration of the new product.
Consumer products may also be regulated by the Food and Drug Administration (FDA).
The FDA has specific requirements which apply to products classified as cosmetics and over-the-
counter (OTC) drugs. The OTC drugs must comply with a monograph issued as part of the
FDA's Over the Counter Drug Review or be subject to a new drug application (NDA). Because
the NDA process is extremely time and resource intensive, compliance with the FDA monograph
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is the more practical means of meeting the FDA requirements. The monograph defines those
ingredients which are safe and effective for use in personal care products classified as OTC
drugs (e.g., underarm antiperspirants). The FDA requires that each OTC drug active ingredient
meet monograph specifications and compendial specifications, and that each active and inactive
ingredient must be safe, not interfere with product efficacy, meet compendia! specifications, and
comply with color additive requirements. Furthermore, each final product formulation must
meet monograph effectiveness requirements.
Also subject to FDA regulation are cosmetics. Cosmetics are not required to undergo
premarket approval by the FDA. However, the law requires that the manufacturer of a cosmetic
product ensure that the safety of each ingredient, as well as the final product formulation, is
substantiated prior to marketing. Furthermore, if the product contains color additives, each such
ingredient must be the subject of an existing FDA color additive regulation approving the use
of the ingredient. The FDA has authority to seize or enjoin the sale of any product that does
not comply with these requirements. Although the manufacturer of a cosmetic bears much of
the responsibility for ensuring safety, a change in formulation necessitates a lengthy and
expensive process of safety evaluation that is very similar to that required by FDA for an OTC
drug.
In developing regulations for consumer and commercial products, the EPA will consider
the additional regulatory requirements which may be triggered by product reformulation.
2.4.2.2 Product Substitution
Product substitution is a control measure that involves replacement of existing products
or processes with available substitutes which result in reduced VOC emissions. Within the
context of §183(e), product substitution implies moving from one product to a different product,
process, or application method. An example of product substitution would be replacement of
an aerosol spray paint with a brush-on paint. Substitution may or may not be a more onerous
control measure than reformulation, depending on whether there would be plant closures,
layoffs, or other adverse impacts resulting from the prohibition of a product or process.
2.4.2.3 Repackaging
Product repackaging is listed as one of the control measures available to the EPA in
reducing emissions from consumer and commercial products. Repackaging is the placement of
an existing product (i.e., the product formulation would not be changed in any way) into
packaging designed such that spillage, leakage, and evaporation are minimized. An example of
repackaging would be replacement of a screw cap container for a cleaning solvent with a squeeze
bottle or other dispenser which would help prevent spillage if the container is upset, and would
minimize evaporation of the solvent while the container is open. Repackaging alone would not
necessitate reformulation of the product.
2.4.2.4 Directions for Use, Consumption, Storage, and Disposal
This measure consists of providing the users of the products specific directions for
handling, using, and disposing of the products in a responsible manner. This technique could
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be employed to reduce VOC emissions from the use, consumption, storage, and disposal of high-
VOC products for which there are no lower-VOC alternatives (e.g., paint thinners, cleaning
solvents, rubbing alcohol, etc.). Although it would be impossible to predict the VOC reductions
•achieved by providing the consumer with directions for use, consumption, storage, and disposal
of a product, this approach could result in some degree of reduction, especially in the case of
high-volume, high-VOC products.
An extension of this control measure would be consumer education. Education concerning
the use of consumer and commercial products may be an important and necessary adjunct to
reformulation, product substitution, repackaging, and directions for use, consumption, storage,
and disposal. Because of the inability to control consumer use, handling, and disposal patterns
once the product is purchased, lack of awareness on the part of consumers can result hi
unnecessary or excessive use of some VOC-containing products. Education that informs and
influences consumers to practice low-VOC emission measures, including informed selection and
proper use, handling, and disposal of consumer and commercial products, is essential as a
control in itself and in conjunction with other control measures to augment their effectiveness.
This measure could be implemented through product labeling, via public information media,
and/or by dissemination of information to other federal agencies and State and local agencies
involved with consumer product safety, recycling, waste disposal, etc.
2.4.3 Systems of Regulation
Section 183(e) gives the EPA a choice of systems of regulation which could be used to
implement the various control measures. These approaches range from product registration to
product prohibition. Economic incentives are also available and could be used alone or hi
conjunction with other approaches and may provide flexibility while promoting development of
lower-VOC-emitting products and/or processes.
2.4.3.1 Product Registration and Labeling
Product registration consists of companies providing information to the appropriate
regulatory agency concerning the products manufactured or marketed by the companies. This
information could range from merely the names of the products and manufacturers to
information on the product formulations, VOC content, and quantity produced. Registration
could enable regulatory agencies to identify the vast universe of manufacturers, processors, and
distributors subject to a specific rule and would facilitate compliance assurance. Another
application of registration would be to provide the regulatory agencies with information which
could be used to establish baseline VOC allocations which could then be used in the
implementation of an economic incentive regulatory approach.
Product labeling is one approach to implementing the control measure described as
"directions for use, consumption, storage, and disposal" of products. Reductions could be
brought about in two ways: (1) product labeling which allows the consumer to make
environmentally informed purchasing decisions; and (2) product labeling which includes
instructions for use, consumption, storage, and disposal of the product in a manner which would
minimize VOC emissions.
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Product labeling has been demonstrated to be an effective means of affecting the
environmental purchasing decisions of consumers. A national survey conducted in 1989 by the
Gallup Organization found that 96 percent of women and 92 percent of men said they would
make a special effort to buy products from companies trying to protect the environment. Eighty-
seven percent of consumers have also stated they were willing to spend 5 to 15 percent more for
environmentally preferable products or packaging.
Environmental labeling has already been employed by some manufacturers to promote the
sale of their products. This "green labeling," however, sometimes tends to mislead the
consumer regarding the true environmental impacts of products. Consequently, the Federal
Trade Commission (FTC) continues to monitor "green labeling" activities and is developing
specific guidance on permissible labeling practices. Accordingly, any rulemaking requiring or
allowing environmental labeling should be carried out with close coordination with the FTC.
2.4.3.2 Self-Monitoring and Reporting
Successful implementation of any control measure requires some degree of compliance
assurance. Because of the vast array of products and regulated entities potentially subject to
§183(e), self-monitoring and reporting by the manufacturers, processors, and/or distributors of
the products may be an effective means of establishing baselines and tracking compliance. This
approach could be complemented by compliance checks and/or audits performed by the
enforcing authorities.
The primary objective of self-monitoring is to make available any information necessary
to determine compliance with an implemented control measure. Self-monitoring in the context
of §183(e) could consist of the regulated entities keeping records of product formulations,
quantities of products sold, types and amounts of feedstocks purchased, names of suppliers
and/or downstream distributors supplied, or combinations of these or other types of information.
The collected information could be accessed by the enforcing agency through requirements for
self-reporting and/or through on-site compliance audits.
In the context of §183(e), reporting could involve submission of information concerning
the identity of a regulated entity, information collected through self-monitoring, or any
information held by a regulated entity which would facilitate compliance assurance. For
example, the most elementary form of reporting would be a requirement for all parties subject
to a particular rule to identity themselves as regulated entities. A more substantive requirement
would be for each regulated entity to report annual sales and formulations for each product
subject to a rule. The content and frequency of required reports would be based on the
enforcement considerations associated with a specific rule.
Because self-monitoring and reporting requirements would require expenditure of time and
resources on the part of the regulated entities, mis approach should be applied judiciously. The
burden imposed on the regulated community should be considered carefully. On the other hand,
certainty of compliance and government resources required for enforcement activities are also
valid considerations. Consequently, successful implementation of any control measure must be
based on consideration of enforcement needs, certainty of compliance, cost to the government,
and burden imposed on the regulated entities.
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2.4.3.3 Prohibitions
Prohibition of certain high-VOC products could also be adopted as a means of reducing
VOC emissions. Because prohibition may have more severe adverse economic impacts than
other systems of regulation, prohibition of individual products, product types, or product forms
should be considered only after other approaches have been exhausted.
2.4.3.4 Limitations
Many existing regulations affecting consumer and commercial products are based on VOC
content limits. For example, coatings are generally limited to a certain number of grams VOC
per liter of coating. Most consumer product regulations promulgated by the States impose
specific limits for percent VOC content by weight.
2.4.3.5 Economic Incentives
Economic incentives are listed among the systems of regulation available under §183(e).
Specifically mentioned are marketable permits and auctions of emission rights. In some cases,
economic incentive programs may be superior to VOC content limitations as strategies to reduce
emissions from consumer and commercial products. In other situations, a combination of VOC
content limitations and economic incentive approaches may provide significant advantages.
The optimal selection of a regulatory strategy depends on the specific characteristics of
the universe of sources being regulated. Potential abatement cost savings, administrative and
monitoring costs, and distributional implications of employing economic incentive strategies to
regulate different consumer and commercial product industries may vary significantly.
Selection of a regulatory strategy also depends upon the program's objectives. For
example, to stimulate technological advancement, a marketable permit program using auctions
may be preferable. Alternatively, if distributional considerations are important, a permit
program with freely granted permits, or perhaps a fee program with rebates, might be
preferable. Similarly, if certainty of emission reductions is a primary objective, (especially if
product efficacy problems exist), marketable permit programs may be preferable, but might be
an undesirable approach if protecting consumers from potential future product price increases
is a primary goal.
Emission fee programs can be used to obtain real and quantifiable reductions in the
emissions of VOC from consumer and commercial products. The basic rationale for these
programs (and economic incentive programs hi general) is to bring the full "social cost" of using
VOC into the economic system. A fee on the emission of VOC would increase the cost of using
the atmosphere as a waste sink. The fee would have the same effect as the prices for the goods
and services exchanged in conventional markets: for example, manufacturers would economize
on then- use of VOC because the "price" of using VOC would be higher, just as they would
economize on the use of labor if wage rates were to increase. Such a fee system would act as
an incentive for manufacturers to reduce the VOC content of products. This is one of several
economic incentive approaches that may be used under §183(e).
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Designing a fee program to reduce VOC emissions from consumer and commercial
products presents many choices. Many of these design options are summarized in Chapter 7.
Tradeoffs are intrinsic to regulatory policy design. The best regulatory strategy for consumer
and commercial products depends upon the particular universe of products being regulated and
the priority of objectives. The EPA will weigh the desirability of economic incentive approaches
in the context of individual rulemakings, in light of public comments and consultation with
interested parties.
2.5 REGULATORY ENVIRONMENT SURROUNDING CONSUMER PRODUCTS
Household consumer products as sources of VOC emissions have been subject to
increasing scrutiny over the past several years. This is due primarily to the intractability of the
ozone nonattainment problem, and the resulting need to focus attention on even the least of VOC
emission sources. Consumer products are recognized as a potential source of emission
reductions by not only the Clean Air Act Amendments of 1990 but by several State and local
air pollution agencies.
2.5.1 The Clean Air Act Amendments of 1990 - Rate of Progress Requirements
The Act, as amended November 1990, classifies areas that exceed national health-based
air quality standards based on the severity of their pollution problem. Specifically, §182(b)
prescribes increasingly stringent measures that must be implemented and sets deadlines for
achieving the standards. The Act also establishes specific interim emission reduction
requirements to ensure than progress toward attainment is sustained. By November 15, 1993,
each area of the country designated as moderate or above for ozone nonattainment was required
to submit to the EPA an implementation plan demonstrating how VOC emissions will be reduced
by 15 percent (from the 1990 baseline) by November 1996. Areas which fail to submit or
implement an approvable plan within the applicable time frame are subject to sanctions in the
form of withheld federal highway funds or requirements for new industrial sources to offset
emissions. Currently, there are 55 areas across the country which are classified as moderate or
above for ozone nonattainment and, therefore, are subject to the 15 percent rate of progress
requirement.
This requirement of the Act has prompted State and local agencies to seek out VOC
emission reductions beyond those which have been obtained through regulation of the
conventional mobile and stationary sources of emissions. Consequently, consumer products are
being targeted for regulation by State and local air pollution authorities.
2.5.2 State and Local Regulation of Consumer Products
Several State and local agencies have adopted rules to regulate various consumer products.
New York's first consumer products rule, 6 NYCCR 235, covering consumer insecticides, air
fresheners, and disinfectants, was adopted in September 1988. Subsequently, New York adopted
a regulation to limit the VOC content of antiperspirants, deodorants, and hair sprays. Since the
late 1980's, Texas has limited the VOC content of windshield washer fluids in Dallas and
Tarrant Counties; other areas of Texas have recently become subject to that rule.
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Because of the severity of its ozone nonattainment problem, California has led the nation
in the move to reduce VOC emissions from consumer products. The California Air Resources
Board (CARB) adopted its regulation for antiperspirants and deodorants in 1990, and has
expanded the consumer products program to include regulations which now cover 27 categories
of products. California's South Coast Air Quality Management District (SCAQMD) and Bay
Area Air Quality Management District (BAAQMD) have implemented local rules for charcoal
lighter fluids and aerosol spray paints, respectively. The SCAQMD charcoal lighter fluid
emission standard and test method are used in the CARB rule. Currently, CARB is nearing
completion of an aerosol spray paints rule.
The Clean Air Act rate of progress requirements have caused several other States to adopt
or begin development of consumer products rules. In September 1993, the State and Territorial
Air Pollution Program Administrators (STAPPA) and the Association of Local Air Pollution
Control Officials (ALAPCO) published a guidance document entitled Meeting the 15-Percent
Rate-of-Progress Requirement Under the Clean Air Act: A Menu of Options to enable the State
and local agencies to develop regulatory programs to meet the November 1996 rate of progress
milestone. Included in the document are chapters covering consumer products and aerosol spray
paints. The STAPPA/ALAPCO recommendations for VOC standards for consumer products
are based on the CARB regulations. The spray paint recommendations are based on the
BAAQMD rule.
Generally, the CARB rule, as presented in the STAPPA/ALAPCO guidance, has been
used as a model by other States in developing their own rules. As of December 1994, States
which had adopted or were in the process of developing consumer products regulations included
Arizona, Connecticut, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island,
Texas, and Wisconsin.
2.6 SPECIAL CONSIDERATIONS CONCERNING CONSUMER PRODUCTS
States have moved to develop rules because consumer products as a group contribute
significantly to the unhealthy levels of ozone pollution that exist in many parts of the country.
In response, industry representatives have urged the EPA to issue national rules limiting VOC
content in many consumer products. Consumer products are used in every household, business,
and institution in the country. Adoption of a multitude of individual State and local regulations
for consumer products, each of which potentially having different applicability, content limits,
labeling, reporting requirements and other features, could prove very disruptive to the national
distribution network for consumer products.
Prompted by these considerations, the EPA calculated projected emission reductions that
may be achievable through federal regulation of consumer products. In the near future, the EPA
will decide whether to include consumer products in its list and schedule for regulations to be
published pursuant to §183(e) of the Act. If a federal consumer products rule is to be of use to
the States in meeting their IS percent rate of progress demonstrations, the rule would have to
be promulgated and in effect (i.e., reductions must be made) no later than November 15, 1996.
In order to develop an estimate of VOC emission reductions which may be obtained
through implementation of a federal rule for consumer products, determinations must be made
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on (1) which product categories might be included in a rule which could be effective by
November 1996; and (2) VOC content limitations for the respective categories covered by the
rule. As an example, the EPA estimated the effectiveness of extending existing State consumer
product rules to nationwide applicability.
For purposes of this demonstration, the product categories selected for inclusion are based
on the STAPPA/ALAPCO guidance (i.e., the CARB rule) and include only those categories for
which the CARB standards will be effective by November 1996. Nationwide emission
reductions were estimated for the product categories covered by the CARB rule by using the
1990 formulation and sales data collected through the EPA's consumer products survey
(discussed in Section 5.1) combined with the VOC content limits listed in CARB's table of
standards. For each product category covered by the survey, the distribution of product sales
(tons of product) versus VOC content (percent VOC) was plotted on a histogram. Emissions
were corrected for fate in wastewater and percent market share captured by the survey as
explained in Section 5.3. For two categories (floor polishes and waxes, and household
adhesives), estimates of emission reductions could not be made because of either inconsistencies
in categorization between the CARB rule and the EPA survey data or limitations of the
histograms. In one case (charcoal lighter materials), the CARB rule is based on an emission
standard (mass of VOC emitted per start) rather than a VOC content limitation.
The first step in performing the emission reduction calculation was to determine each
category's nationwide baseline emissions from the survey data. Then, using the histogram, all
products in that category with VOC contents above the standard were moved into compliance
(i.e., product tonnage was multiplied by the content standard) to yield a new emission estimate.
Products originally at or below the CARB standard were not moved up to the limit; only
noncomplying products were changed.
After applying the above procedure to the 21 categories which could be assessed, emission
reductions were estimated to range from zero percent (for nonaerosol antiperspirants and
deodorants) to 73 percent (for lawn and garden insecticides). The overall, weighted average
reduction was approximately 25 percent. (For the purpose of making a preliminary estimate of
the effectiveness of a federal rule, a similar overall percent reduction for the remaining five
categories was assumed.) As a result, annual nationwide emission reductions through
implementation of a hypothetical federal rule covering all 24 categories was estimated to be
approximately 121,000 tons per year, or about one pound per capita (based on a 1990 U.S.
population of 248 million). Table 2-3 presents the results of this assessment.
2.7 REFERENCES
1. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Alternative Control Techniques - Control Techniques for Volatile Organic
Compound Emissions from Stationary Sources (EPA-453/R-92-018), December 1992.
2. Dimitriades, B., Scientific Bases of the VOC Reactivity Issues Raised by Section 183(e)
of the Clean Air Act Amendments of 1990, U.S. Environmental Protection Agency, Office
of Research and Development, Atmospheric Research and Exposure Assessment
Laboratory, Research Triangle Park, North Carolina, 1994.
2-18
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TABLE 2-3
ESTIMATED EMISSION REDUCTIONS FROM CONSUMER PRODUCTS
Product Category
Aerosol Cooking Sprays
Air Fresheners ' (single phase)
(double phase)
(liq. & pumps)
(sol. & gels)
Auto Windshield Washer Fluids 2
Bathroom and Tile Cleaners 3
Carburetor and Choke Cleaners
Charcoal Lighter Materials 4
Dusting Aids (aerosols)
(other forms)
Engine Degreasers 5
Fabric Protectants
Floor Polishes and Waxes '
(Flexible)
(Nonresilient)
(Wood)
Furniture Maintenance Products
General Purpose Cleaners
Glass Cleaners 7
Hair Sprays
Hair Mousses
Hair Styling Gels
voc
Limit
(percent)
18
70
30
18
3
10, 35(cold)
5, 7(aero)
75
see note
35
7
75
75
7
10
90
25
10
8, 12(aero)
80
16
6
Baseline
Emissions
(tons/yr)
2,720
8,078
12,372
8,029
397
80,522
1,356
5,873
3,961
345
276
2,860
1,097
3,860
3,585
1,413
15,461
179,613
2,421
622
Controlled
Emissions
(tons/yr)
1,768
6,139
10,764
8,029
151
53,145
949
4,522
2,971
169
185
2,317
878
2,895
3,083
579
6,648
150,875
1,743
174
Emission
Reduction
(tons/yr)
952
1,939
1,608
0
246
27,377
407
1,351
990
176
91
543
219
965
502
834
8,813
28,738
678
448
Emission
Reduction
(percent)
35
24
13
0
62
34
30
23
25*
51
33
19
20
25'
14
59
57
16
28
72
2-19
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TABLE 2-3 (Continued)
ESTIMATED EMISSION REDUCTIONS FROM CONSUMER PRODUCTS
Product Category
Household Adhesives '
(aerosol)
(contact)
(constr/panel)
(gen purpose)
Insecticides (crawling bug)
(flea and tick)
(flying bug)
(foggers)
(lawn/garden)
Laundry Prewash (aer & solid)
(other forms)
Laundry Starch Products
Nail Polish Removers '
Oven Cleaners 10
Shaving Creams
Underarm Antiperspirant " (aero)
(others)
Underarm Deodorant " (aero)
(others)
ALL CATEGORIES
vex:
Limit
(percent)
75
80
40
10
40
25
35
45
20
22
5
5
85
5, 8(aero)
5
60
0
20
0
Baseline
Emissions
(tons/yr)
67,608
17,179
3,739
5,753
3,663
8,799
529
337
6,033
6,287
1,825
95
5,456
18,264
1,364
4,566
486,358
Controlled
Emissions
(tons/yr)
50,706
7,215
1,196
2,646
2,234
2,376
354
337
3,740
5,595
1,022
60
5,347
18,264
1,146
4,566
364,788
Emission
Reduction
(tons/yr)
16,902
9,964
2,543
3,107
1,429
6,423
175
0
2,293
692
803
35
109
0
218
0
121,570
Emission
Reduction
(percent)
25*
58
68
54
39
73
33
0
38
11
44
37
2
0
16
0
25
These categories were assessed assuming a reduction of 25 percent based on reduction calculations for the
remaining categories. See text for explanation.
Footnotes continue on the following page.
2-20
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TABLE 2-3 (Continued)
ESTIMATED EMISSION REDUCTIONS FROM CONSUMER PRODUCTS
1. Air fresheners category does not include toilet deodorant blocks.
Current CARB standard for single-phase air fresheners is 70 percent; standard is reduced to 30 percent
1/1/96, but reductions were calculated based on 70 percent limit.
2. Windshield washer emission reduction estimate was calculated assuming that half of the products are
formulated for "cold" areas or seasons. Either a geographic or seasonal applicability provision would need
to be developed.
3. Bathroom and tile cleaners histogram does not specify product form.
4. The CARB charcoal lighter emission standard is 0.020 pounds VOC per start, based on test method specified
in South Coast Air Quality Management District Rule 1174, February 27, 1991. No estimate of emission
reductions was made.
5. Current CARB engine degreaser current standard is 75 percent. This limit is reduced to 50 percent 1/1/96,
but reductions were calculated based on 75 percent standard.
6. EPA survey data on floor waxes and polishes is not separated by type of flooring. No estimate of reductions
was made.
7. Glass cleaners histogram does not specify product form. CARB standard for nonaerosol glass cleaners is
reduced to 6 percent 1/1/96, but reductions were calculated based on currently effective 8 percent limit.
8. EPA survey data on adhesives is separated into 10 categories which do not correspond with CARB
categories. No estimate of reductions was made.
9. Current CARB standard is 85 percent. Standard is reduced to 75 percent effective 1/1/96, but calculation
was based on 85 percent. Acetone, the principal ingredient, is currently being considered by EPA for
exemption from the VOC definition.
10. Oven cleaners histogram does not specify product form.
11. The CARB standards for underarm antiperspirants and deodorants refer to content of "high volatility organic
compounds" (i.e., those VOC with a vapor pressure of greater than 80 millimeters of mercury (mmHg) at
20°C). Because aerosol propellants are the only ingredients of these products with such high vapor
pressures, this measure is, in effect, a limitation on the propellant content of the products.
2-21
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CHAPTER 3
PHOTOCHEMICAL REACTIVITY
Section 183(e) of the 1990 Amendments requires the EPA develop a control strategy for
VOC emissions from consumer and commercial products, taking into account the photochemical
reactivities of such emissions. Specifically, the Administrator is required to (1) determine the
potential of VOC emissions from consumer and commercial products to contribute to ozone
levels which violate the NAAQS for ozone; (2) consider those products which emit "highly
reactive" species of VOC; and (3) list those consumer and commercial products that account for
at least 80% of the VOC emissions on a "reactivity-adjusted" basis in ozone nonattainment areas.
To meet these requirements, the Administrator must have either appropriate, quantitative data
on the ozone-forming potentials, commonly referred to as "reactivities," of all VOC emission
species associated with consumer and commercial products, or some other method for
characterizing the impact of such VOC emissions on ambient ozone. Such data and methods
currently exist but are known to have uncertainties and other limitations.
The purpose of this chapter is to present, explain, and discuss the validity, uncertainties,
and overall utility of existing reactivity data and methods in relation to the requirements of
§183(e). This chapter first discusses the chemistry underlying the reactivity property of VOC.
Limitations of existing reactivity data and the use of such data are discussed, including those
related to the reactivity concept itself, and those associated with experimental error. Finally,
different existing and proposed VOC reactivity classification schemes and reactivity estimation
methods are described and discussed with respect to their relative usefulness in meeting the
requirements of §183(e).
This discussion, which is simplified to the greatest extent possible, is intended to present
the EPA's understanding of the current science in as readable a way as possible for the benefit
of those interested in the reactivity issues related specifically to consumer and commercial
products. Therefore, the emphasis is on pertinent conclusions and on uncertainties inherent in
the scientific evidence underlining those issues, rather than on in-depth and comprehensive
description of the "reactivity" science. This results in occasional simplifications of scientific
concepts.
3.1 THE CHEMISTRY OF "REACTIVITY"
In the presence of oxygen (O2>, and with the stimulus of sunlight radiation, nitrogen
oxides (NO+NO2 or NOX) react in the atmosphere to form ozone (03) and nitric oxide (NO)
through reactions (1) and (2) below. Resultant ozone, however, is rapidly destroyed by reacting
with NO and converting it back to N^, reaction (3). Sources of NOX include combustion
associated with stationary sources (e.g., power plants) and mobile sources (e.g., automobiles).
NO2 + sunlight -» NO + O (1)
O + 02 -» O3 (2)
O3 + NO -* NO2 (3)
3-1
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Ozone, therefore, cannot be accumulated in the atmosphere unless NO is converted back
to NO2 through some other process. Such a process exists, and occurs when VOC pollutants
are present. In the presence of VOC, NO is converted into NO2 through the chain reaction
process shown below1, where "17" is the number of NO2 molecules formed for each VOC
molecule consumed in reaction (3).
ubiquitous OH radicals + VOC - RO2 radicals (4)1
NO NO NO
RO2 •* NO2 + R'O2 -» -» i?NO2 + OH + products (5)
(step 1) (step 2) (step ij)
The ultimate amount of accumulated ozone depends on the nature and concentration of
VOC present and the concentration of NOX. In VOC-deficient and NOx-rich atmospheres ozone
formation is inhibited by NOX due to ozone- and radical-scavenging reactions [mainly reactions
(3) and (6)], and very little ozone ultimately accumulates. Ozone formation is favored in VOC-
rich atmospheres where the ij molecules of NO2 could result in as many as 17 molecules of
ozone.
NO2 + OH -» HNO3 (6)
ry
Different VOC species have different ozone-forming potentials or reactivities^ for four
reasons:
(a) their kinetic reactivities differ, that is, the rates, k0H, at which they react in the
atmosphere [reaction (4)] differ (see footnote 1);
(b) their mechanistic reactivities differ, that is, the amounts of N(>> (and consequent
amounts of ozone) they yield through reaction (5) [and follow-up reactions (1) and
(2)] differ;
(c) they increase or reduce the ambient OH pool to different degrees, thus causing the
other VOC present in air to participate more or less vigorously in the ozone-forming
process; and
1 Besides the reaction with OH, some VOCs are consumed also, to widely varying
degrees, through photolysis and reactions with 03, O-atoms, and NO3 ~ processes which
also result in RO2 radicals. The propensity of a VOC species for such reactions is often
referred to as "kinetic reactivity". However, for the bulk of the VOC species encountered in
polluted atmospheres, the reaction with OH is the main RO2-producing process, and, for this
reason, the term "kinetic reactivity" is used here to denote the rate of reaction, KQH, for
reaction (4).
3-2
-------
(d) they deplete the reaction system of the NOX reactant to different degrees.
Mechanistic reactivity refers to the amount of ozone produced through reaction of a given
amount of a VOC species (i.e., the yield). Many VOC species, such as long carbon-chain
compounds, benzaldehyde, phenol, and others, react relatively fast with HO radicals, but are of
low mechanistic reactivity. Others, such as C4 - Cg paraffins are of relatively low kinetic
reactivity but produce NO2, and potentially ozone also, in high yields. Olefins, polyalkyl-
substituted benzenes, and aliphatic aldehydes are highly reactive in both respects. Low reactivity
VOC can still be significant ozone producers if they occur at high concentrations, and under
favorable conditions [e.g., carbon monoxide (CO)].
The kinetic reactivity of a VOC species (i.e., the rate of reaction) is an intrinsic property
of the molecule, unaffected by other pollutants in the atmosphere. In contrast, the mechanistic
reactivity, and, ultimately, the ozone-forming potential of a VOC species is strongly influenced
also by other VOC and the VOC-to-NOx ratio in ambient air, and other conditions. In general,
conditions that affect the influence of the VOC factor in the ozone-forming process also affect
the mechanistic reactivities and, ultimately, the ozone-producing potentials of VOC.
Specifically, lower VOC-to-NOx ratios and lower-reactivity ambient VOC mixtures tend to
enhance a given VOC species' ozone-forming potential. These effects have two significant
implications:
(1) The concept of VOC reactivity has practical utility only in VOC-limited atmospheres, that
is, in atmospheres in which the influence of the VOC factor on the ozone-forming process
is stronger than that of the NOX factor, and for which atmospheres, therefore, VOC
control is the optimum approach to ozone reduction. Such atmospheres are, for example,
those above the center-city sections of most urban areas. In VOC-rich atmospheres, the
application of reactivity, or any other VOC control measure, will be less effective than
NOX control. VOC-rich atmospheres are, for example, those within "aged" urban plumes,
depleted of NOX, and atmospheres above densely vegetated urban areas.
(2) The ozone-forming potentials of VOC species vary, both absolutely and relative to each
other, with ambient conditions. Thus, reactivity-related VOC-control measures cannot be
expected to have the same impacts in all atmospheres. This is a limitation of the reactivity
concept, but not necessarily a prohibitive one. This is because, for atmospheres for which
VOC control is the optimum approach to ozone reduction, the effect of variation of
ambient conditions on reactivity is small compared to the reactivity differences among
different VOC species.
3.2 THE MEASUREMENT OF REACTIVITY
In early studies, gross measures of reactivity of VOC were obtained through smog
chamber tests in which the various VOC species were tested individually under irradiation
conditions simulating a single solar day.-* Such reactivity data presently exist for a significant
number of VOC species. Later developments led to the requirement to test a VOC species more
realistically, that is, in the presence of an "urban VOC mix", and under irradiation conditions
simulating both single-day and multi-day transport of pollutants in the atmosphere. Such smog
chamber tests generally provide reasonably reliable and useful data, but are tedious, costly, and
3-3
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unreliable for low reactivity VOC. For these reasons, only very few VOC have been tested to
date in this fashion. Furthermore, complete reactivity characterization of a VOC species
requires several smog chamber tests covering the range of VOC-to-NOg ratios, VOC
composition, and radiation conditions occurring in the various nonattainment atmospheres.
These difficulties and requirements led to development of what is referred to as the
method, a method now normally used for identifying negligibly reactive VOC, and the
"Incremental Reactivity" (IR) method', more appropriate for rating reactive VOC. The "kpjj
method" entails experimental measurement of the rate at which the VOC is consumed in reaction
with OH. The method is commonly used for measurement of a VOC's reactivity relative to that
of a reference VOC species. In this method, it is assumed ~ not always a 'valid assumption, as
explained later - that ICQJJ is an indicator of the VOC species' ozone-forming potential. The
IR method entails laboratory studies of the VOC species to derive a mechanistic model
describing the species' atmospheric chemistry, and the use of a computer model to compute an
estimate of the species' contribution to ambient ozone for any set of atmospheric conditions.
Of the two recent reactivity measurement methods, the I£QH method entails measurement
of KQH that can be made very accurately. The method's accuracy, however, with respect to
determining the effect of VOC on ambient ozone is limited due to the fact that ICQJJ does not
reflect ozone potential for all VOC. Specifically, long carbon-chain VOC, some aromatic
oxygenates, and hydroxylamines have relatively high kqjj values but disproportionately low,
even negative, ozone-forming potentials. The IR method is conceptually more valid in this latter
respect, but it also has its drawbacks. Specifically, the accuracy of the IR method, first,
depends on how well the atmospheric chemistry of the VOC is known. Such chemistry has
been judged by University of California at Riverside (UCR) experimentalists to be relatively well
known for only 13 VOC - out of some 328 species or groups of species considered." In
addition to the chemistry uncertainties, the IR data suffer also from a conceptual uncertainty
arising from the fact that ambient conditions affect absolute and relative incremental reactivities.
To illustrate this latter effect, "Maximum Incremental Reactivities" (MIR), derived by UCR for
generally low VOC-to-NOx ratio conditions, were compared with "Maximum Ozone (yield)
Incremental Reactivities" (MOIR), derived for generally higher ratio conditions. Results showed
that the MIR and MOIR values correlate well but not without significant scatter. It should be
stressed, however, that this conceptual uncertainty of the IR method, first, as already mentioned,
is not of serious consequence, and, second, it arises from the chemistry of the ozone process,
and, hence, affects all methods for measuring ozone-potential reactivities.
Given these relative strengths and limitations of the kQH and IR reactivity methods, it is
of interest to know how data by the two methods compare. Such a comparison indicates some
correlation but with a large amount of scatter. It should be noted here that Carter's IR data
compared well with ozone-potential data computed through use of photochemical grid models. '
The overall judgment adopted here, and favored by some (McNair)7 - but not all (Jeffries &
Grouse)8 - experts, is in favor of the IR data, mainly because such data provide the most
appropriate means for quantifying the effect of VOC on ambient, episodic ozone through use of
reactivity methods. The need, however, for continuing research to obtain more reliable MIR data
for VOC emitted from consumer and commercial products is, clearly, an important and urgent
one.
3-4
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The protocol presently favored - but not officially endorsed - by EPA for reactivity
testing of a VOC species, calls, first, for a measurement of the species' kgH reactivity relative
to that of ethane - a species whose reactivity, as explained below, is unofficially used by EPA
as the borderline separating reactive from negligibly reactive organics. If such reactivity is found
to be equal to or lower than that of ethane on a per-grant-of-VOC basis2, and there are no
other VOC-loss reactions, it is concluded that the VOC species can only have negligible Oj.
potential, and no further testing is required. If its k^-reactivity is greater than that of ethane,
then the EPA will assume the VOC species to be reactive unless other evidence is obtained that
shows lower ozone- potential relative to ethane, k/w-reactivity data have been obtained or
estimated for nearly all VOC species of interest.*^ Incremental Reactivity data have been
obtained, estimated, or surmised by UCR researchers for some 328 VOC species or groups of
species. IR data were also compiled by Hartwell Laboratory investigators in England10, and
by the Swedish Environmental Research Institute. These European data, however, were
derived for northern Europe conditions, and, therefore,are less appropriate for use in the U.S..
3.3 REACTIVITY SCALES
Of the various reactivity scales used or proposed in the past, EPA adopted first, in 1977,
a three-class scale ("negligibly reactive", "low-reactive", "reactive") , and later the two-class
scale {"negligibly reactive", "reactive") implied by the "VOC" definition put into effect in
1992. ™ in both cases, "negligibly reactive" VOC are certain listed species judged by EPA —
based mainly on smog chamber and/or kQH data — to have insignificant ozone-forming
potentials. "Reactive VOC" are all those judged to be clearly more reactive than ethane — the
most reactive member of the "negligibly reactives" class. Finally, "low-reactive" VOC are all
those of borderline reactivity, i.e. , those for which existing data do not clearly support inclusion
in either the class of negligibly reactive or the class of reactive VOC. These group-reactivity
scales are practical, but their usefulness is severely limited by the inherent assumption that all
species within the class of "reactives" are of equal reactivity when, in fact, their reactivities
differ by more than an order of magnitude.
In contrast to those first reactivity scales, the more recent kQjj and IR scales entail very
little grouping of VOC, i.e., the various VOC species are assigned reactivity ratings mostly
individually. Assuming that these ratings are accurate, this is yet another advantage of the kQjj
and IR scales over the earlier scales.
3.4 APPROACHES TO DEVELOPING REACTIVITY-BASED CONTROL STRATEGIES
There are two proposed approaches to developing reactivity-based control strategies:
through use of reactivity scales such as those described above, and through application of an air
z Comparison of VOC species reactivities to that of ethane can be made either on a per-
gram-of-VOC basis or a per-mole-of-VOC basis. Given the relatively low molecular weight
of ethane, use of the per-gram basis, obviously, tends to result in more VOCs (high-
molecular-weight ones) falling into the "negligibly reactives* class, relative to the per-mole
basis. EPA's Office of Air Quality Planning and Standards (OAQPS), with responsibility for
regulatory actions in this area, has unofficially adopted the per-gram basis.
3-5
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quality simulation model (AQSM). In the reactivity scale approach, ozone-forming potentials of
different VOC emission mixtures are estimated from mixture composition and species reactivity
data through simple linear summation calculations. Of the two approaches, this is the simpler
but also less credible one, and is of limited geographical scope.
The AQSM approach entails use of airshed models to compute impacts on ambient ozone -
- throughout the urban area - of modifications of the VOC emission mixture. It is the more
credible approach, but is also extremely complex and costly. Both approaches suffer from
uncertainties and other limitations, the seriousness of which depends on the specifics of the
control strategy needed. Application of the two approaches in meeting the three specific
requirements of §183(e) is discussed below.
3.5 MEETING THE REQUIREMENTS OF §183(e)
Reactivity and the causal relationship between VOC emissions and ozone formation is
addressed three times in §183(e), although reactivity is mentioned explicitly only twice. The
following sections present approaches to meeting the reactivity-related requirements of the Act.
3.5.1 Role of Consumer and Commercial Products in Ozone NOTfrflfoiprpCT*
One objective of the study of consumer and commercial products, as stated in
§183(e)(2)(A)(i) is to "determine their potential to contribute to ozone levels which violate the
national ambient air quality standard for ozone . . "
Although reactivity is not mentioned explicitly here, such potential is understood to be the
ozone contribution of the consumer and commercial product VOC relative to that of the ambient
VOC in their totality. A measure of this potential can be obtained from concentration and
reactivity data for all VOC species in the nonattainment atmosphere through a linear summation
calculation, i.e.,
CCP-O^-Potential = - - - - 2L1 (7)
where CCPCVOQj and TJ are the weight-fraction and reactivity, respectively, of CCP VOC
species i, and AMB(VOC): and n are the weight-fraction and reactivity, respectively, of ambient
VOC species j. This reactivity scale method is simple but requires that reactivity data exist for
all VOC emission species emitted by consumer and commercial products. The consumer and
commercial product emissions, however, unlike, e.g., automotive emissions, do not have a
history of studies, and existing reactivity data, therefore, are either largely incomplete or
uncertain. The method also suffers from uncertainties, mainly in the reactivity data themselves -
- the reactivity chemistry for most of these species is not well known - and in the linearity
assumption used in equation (7). Overall, the reactivity scale method should be viewed as
providing only approximate results.
3-6
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The CCP-O3-Potential can also be estimated through AQSM computations of ozone
formed in the presence and in the absence of the consumer and commercial product VOC, for
any set of ambient conditions. Such estimates are clearly more reliable and useful than those
derived by the reactivity scale approach. However, they, also, are not without significant
uncertainties, and are extremely costly to obtain. Uncertainties are in the chemistry, dispersion,
and emissions components of or inputs to the AQSM models, and, to reduce such uncertainties,
requires costly research and efforts to obtain reliable and complete input data and to field-test
the models. Finally, for universal use, estimates of CCP-Oj-Potential should be based on model
computations for several "representative" nonattainment urban atmospheres.
3.5.2 Highly Reactive Compounds
In establishing criteria for regulating consumer and commercial products, §183(e)(2)(B)
requires that the EPA take into consideration each of five factors, including "(ill) [t]hose
consumer and commercial products which emit highly reactive volatile organic compounds into
the ambient air."
In the absence of pertinent guidelines from the Act, the distinction between "reactive" and
"highly reactive" VOC can only be made with considerable arbitrariness. For the classification
to be effective and practical, the "highly reactive" VOC should be considerably more reactive
than the "reactive" ones, and it should be feasible to selectively control such VOC more cost-
effectively than through indiscriminate VOC control. Lacking detailed information related to the
latter criterion, such a classification could not be and was not developed as part of this report
to Congress. Instead, the EPA used the best judgement to develop a rational and practical
classification.
Specifically, "highly reactive" VOC are proposed to be those with MIR > 4, and include:
Ethyl- and trimethyl-amines, methyl nitrite, unsaturated Cy and C4-esters, furan, aliphatic
saturated C < g-aldehydes, unsaturated C3-aldehydes and dialdehydes except glyoxal, C 50,000 ppm"1 min"1 (the KQH value corresponding to MIR = 4, approximately), and
include: Ethyl- and trimethyl-amines, 2-(2-ethoxyethoxy)-ethanol (carbitol), alkyl-styrenes,
polyalkyl-benzenes with 3 or more alkyl substituents, alkyl-phenols, and C>4-olefins.
The above MIR- and KQH-reactivity classifications of VOC are in disagreement with
respect to the reactivity assignments of carbitol, furan, C ^-aldehydes, alkyl-styrenes, dialkyl-
benzenes, alkyl-phenols, and methyl- and ethyl-acetylenes. To resolve these conflicts, the
reactivities of the "disagreement-VOC" were reassessed in the light of the latest evidence
3-7
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regarding atmospheric photochemistry of those VOC, and results were used to develop a
compromise classification, as explained next.
Smog chamber evidence has established that longer carbon-chain paraffins^, and by
reasonable implication, longer carbon chain VOC in general, and carbitol ,, tend to have lower
ozone-producing potentials than suggested by their kQH values. Existing smog chamber data
also suggest that alkyl-styrenes 15, furan 16, C<6-aldehydes 17, and dialkyl-benzenes17 have
ozone-potentials comparable to those of "highly reactive" VOC. Furthermore, phenol is known
to have a propensity for scavenging radicals and, hence, have low, in fact, negative ozone
potential despite its high ICQJJ- Such evidence is judged to support the MIR-derived reactivity
assignment for phenol and alkyl phenols. On the other hand, in the almost total lack of
experimental ozone-potential data for and methyl- and ethyl-acetylenes, these species were
assigned reactivity ratings consistent with the !CQH data. Finally, the existing reactivity data or
judgments on specific VOC species were used through extrapolations - when such extrapolations
could be made reasonably — to derive reactivity ratings for families or groups of VOC.
As a result of the above considerations, a compromise classification was derived that
identifies "highly reactive" and "reactive" VOC as follows:
Highly Reactive VOC: Nitrites, C < g-alkyl-amines, unsaturated esters, furan, C < g-aldehydes,
C < ^-poly-substituted naphthalenes, alkyl-styrenes, polyalkyl-
benzenes, and C < iQ-olefins.
Reactive VOC: All VOC other than the "highly reactive" ones (listed above) and the
"negligibly reactive" ones (identified in the EPA's definition of
VOC n).
3.5.3 Adjustment of Emissions Inventory Data to Account for Relative Reactivity
The third reactivity-related requirement concerns adjustment of emissions data to account
for relative reactivity. Section 183(e)(3)(A) states that "the Administrator shall list those
categories of consumer or commercial products that the Administrator determines, based on the
study, account for at least 80 percent of the VOC emissions, on a reactivity-adjusted basis, from
consumer or commercial products..."
This requires that the various consumer and commercial product categories be assessed
relative to each other with respect to the levels of "highly reactive" or "reactive" VOC emissions
with which they are associated. Such an assessment can be accomplished reasonably well
through use of a somewhat simplistic methodology based on the "highly reactive" and "reactive"
definitions developed and described above.
In order to make the required adjustment to emissions data for a given product category,
the emissions of each "highly reactive" compound could be weighted through application of a
reactivity adjustment factor. This adjustment factor could be equal to the ratio of the MIR of
the highly reactive compound to some reference MIR as shown in equation (8),
3-8
-------
*n*M'*t
Reactivity Adjustment Factort = (8)
where MRl^ is the MIR of the highly reactive species, and MIR^t is the MRI used as the
reference.
In developing this methodology, the EPA considered three choices for MIR^. Recall that
"highly reactive* VOC have been defined above as compounds with MIR > 4. If MIR = 1
were to be selected as the reference MIR, the adjustment factor would be equal to the MIR of
the species, and even emissions of "reactive" VOC would be subject to adjustment. This would
result in over-adjustment of the "highly reactive" VOC. Another possible reference considered
was the MIR of the most reactive of the "reactive" VOC, or MIR = 4. That choice would
result in too little adjustment, since even emissions of "highly reactive" compounds would
receive only small adjustments. The EPA eventually selected the mid-point MIR of the
"reactive" compounds as a reference, or MIR = 1.875. As a result, the reactivity adjustment
factor for any highly reactive VOC can be expressed as shown in Equation (9).
Reactivity Adjustment Factorl = (9)
The emission estimate for a given product category could then be weighted to account for
relative reactivity by applying the adjustment factor to the mass emissions of highly reactive
VOC ingredients as shown in Equation (10).
Adjusted Emissions = Reactive Mass Emissions + £ (HRCf Mass Emissions)(RAF) (10)
where HRC^ is an individual highly-reactive compound, and RAFf is the reactivity adjustment
factor corresponding to that particular compound.
For example, a product category has annual VOC emissions of 100 tons. Included in the
100 tons are 20 tons of formaldehyde (HRCj) and 10 tons of o-xylene (HRC^). The remaining
70 tons is composed of "reactive" emissions. The MIR of formaldehyde and o-xylene are 7.2
and 6.5, respectively. Based on a reference MIR of 1.875, the reactivity adjustment factors for
the two compounds are RAFj = 3.84 and RAF^ = 3.47. To calculate adjusted emissions, the
formaldehyde tonnage is multiplied by 3.84, the o-xylene tonnage is multiplied by 3.47, and the
three terms ("reactives", formaldehyde, and o-xylene) are then added as shown below.
Adjusted Emissions = 70 + (20)(3.84) + (10X3.47) = 181.5 tons (11)
3-9
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The hypothetical product category would have a reactivity-adjusted emissions estimate of
181.5 tons per year. As a result, the emissions from this category would be weighted almost
double compared to a category with similar mass emissions but with no emissions of highly
reactive compounds.
The methodologies presented in this chapter concerning (1) the potential of consumer and
commercial product VOC to contribute to ozone nonattainment; (2) identification of "highly
reactive" compounds; and (3) adjustment of mass emission estimates to account for relative
reactivity represent the EPA' s best effort and are believed by the EPA to be the most appropriate
way to meet the statutory requirements, given the limitations and uncertainties surrounding the
reactivity issue. Should additional information become available, the methodologies and other
information presented in this report to Congress may change.
3.6 REFERENCES
1. NRC (National Research Council) (1991): "Rethinking the Ozone Problem in Urban and
Regional Air Pollution", National Academy Press, Washington, DC, 1991, and references
therein.
2. Carter, W.P.L. (1991): "Development of Ozone Reactivity Scales for Volatile Organic
Compounds", EPA-600/3-91/050, August, 1991.
3. Dimitriades, B., G.P.Sturm, Jr., T.C.Wesson, and E.D.Sutterfield (1975): "Development
and Utility of Reactivity Scales from Smog Chamber Data", RI 8023, US Bureau of
Mines, 1975.
4. Pitts, J. N.,Jr., A. M. Winer, S. M. Aschmann, W. P. L. Carter, and R.Atkinson (1985):
"Experimental Protocol for Determining Hydroxyl Radical Reaction rate Constants for
Organic Compounds", EPA-600/3-85-/058, June 1985.
5. Carter, W.P.L., and R.Atkinson (1989): "Alkyl Nitrate Formation from the Atmospheric
Photooxidation of Alkanes; a Revised Estimation Method", J. Atm. Chem., &, p. 165
(1989).
6. Carter, W.P.L. (1992): Private correspondence to B.Dimitriades, November 5, 1992.
7. McNair, L., A. Russell, and M. T. Odman (1992): "Airshed Calculation of the Sensitivity
of Pollutant Formation to Organic Compound Classes and Oxygenates Associated with
Alternative Fuels", JAWMA, &, p. 174, (1992).
8. Jeffries, H. and R. Grouse (1991): "Scientific and Technical Issues Related to the
Application of Incremental Reactivities, Part U: Explaining Mechanism Differences", Final
Report to Western States Petroleum Association, October, 1991, School of Public Health,
University of North Carolina, Chapel Hill, N.C..
9. Carter, W.P.L. (1994): "Development of Ozone Reactivity Scales for Volatile Organic
Compounds", JAWMA, 44, P- 881, (1994).
3-10
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10. Derwent, R.G., and M.E.Jenkin (1991): "Hydrocarbons and the Long Range Transport
of Ozone and PAN Across Europe", Atmospheric Environment, 25A, p. 1661, (1991).
11. Anderson-Skold, Y., P.Grennfeld, and K.Pleijel (1992): "Photochemical Ozone Creation
Potentials: A Study of Different Concepts", JAWMA, 4.2, p. 1153, (1992).
12. EPA (1977): "Recommended Policy on Control Of Volatile Organic Compounds", Federal
Register, 42, p. 35314, July 8, 1977.
13. EPA (1992): "Part 51 - Requirements for Preparation, Adoption, and Submittal of
Implementation Plans", Federal Register, 5JZ, p. 3945, February 3, 1992.
14. Carter, W.P.L., J.A.Pierce, I.L.Malkina, D.Luop, and W.D.Long(1993): "Experimental
Chamber Studies of Maximum Incremental Reactivities of Volatile Organic Compounds",
Report to CRC, Inc., CARB, SCAQMD, USEPA, UCAR, and Dow Coming Corporation,
April, 1993.
15. Yanagihara, S., I. Shimada, E. Shinoyama, F. Chisaka, K. Saito, and T. Ishii (1977):
"Photochemical Reactivities of Organic Solvents", Fourth International Clean Air
Congress, Japanese Union of Air Pollution Prevention Associations, pp. 472-477, 1977.
16. Sickles, J. E., H, L. A. Ripperton, W. C. Eaton, and R. S. Wright (1978): "Atmospheric
Chemistry of Potential Emissions from Fuel Conversion Facilities. A Smog Chamber
Study", EPA-600/7-78-029, March 1978.
17. Singh, H. B., H. M. Jaber, and J. E. Davenport (1984): Reactivity/Volatility
Classification of Selected Organic Chemicals; Existing Data", EPA-600/3-84-082, August
1984.
3-11
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CHAPTER 4
CRITERIA FOR REGULATING PRODUCTS UNDER §183(e)
4.1 INTRODUCTION
One objective of the study was to establish criteria for regulating consumer and
commercial products under the Act. The Act lists five factors that must be considered in
developing the criteria. This chapter presents the EPA's interpretation of the meaning and intent
of each of the five factors and develops criteria which address each factor. In addition, two
criteria (magnitude of annual emissions and regulatory efficiency) are presented which are not
directly associated with any of the factors required to be considered, but are believed by the
EPA to be important in establishing the schedule for regulations. Throughout this discussion,
factor refers to one of five considerations which the Act requires the EPA to take into account
in establishing the regulatory criteria. Criterion refers to a parameter by which each product
category is to be assessed in order to establish that category's relative priority for regulation.
A summary of the five factors and the corresponding criteria is presented in Table 4-1.
Application of some of the criteria requires that subjective decisions be made, although
others are based on more objective decisions. Where quantitative evaluation is not feasible,
qualitative methods are employed. The use of subjective judgement, because it raises questions
concerning consistency and equity, has been avoided to the greatest extent
possible. The following sections describe the methodology for applying the criteria and for
eventually assigning a rank or score for each product category within the scope of §183(e).
Please note that throughout this chapter a higher score for a given criterion generally
indicates that the product category tends to have higher priority for regulation with respect to
that criterion. Furthermore, a very high or very low score for a single criterion does not
necessarily predict the outcome of the ranking; the composite score obtained from application
of all the criteria will be the primary basis for a category's priority for regulation. It should also
be noted that the EPA plans to establish priorities for regulation based on the criteria presented
in this report to Congress. However, the priorities established may change at any time prior to
the decision to regulate a particular product category if warranted.
4.2 FACTOR 1: USES, BENEFITS AND COMMERCIAL DEMAND
4.2.1 Key Terminology
Use: The purpose for which the product exists.
Benefit: Value from use; usefulness; something for the good of a person or thing.
Commercial Demand: The quantity of a commodity bought at a specific market price.
4-1
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TABLE 4-1
SUMMARY OF FACTORS AND CRITERIA
Factor 1: The uses, benefits, and commercial demand of consumer and commercial products.
• Criterion 1 - Utility
• Criterion 2 - Commercial demand
Factor 2: The health or safety functions (if any) served by such consumer and commercial
products.
• Criterion 3 - Health or safety functions
Factor 3: Those consumer and commercial products which emit highly reactive VOC into the
ambient air.
• Criterion 4 - Emissions of "highly reactive" compounds
Factor 4: The availability of alternatives (if any) to such consumer and commercial products
which are of comparable costs, considering health, safety, and environmental
impacts.
• Criterion 5 - Availability of alternatives
Factor 5: Those consumer and commercial products which are subject to the most cost-
effective controls.
• Criterion 6 - Cost-effectiveness of controls
Additional Considerations
• Criterion 7 - Magnitude of annual VOC emissions
• Criterion 8 - Regulatory efficiency
4-2
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4.2.2
Criteria 1 and 2
Two criteria result from the interpretation of Factor 1. Criterion 1 addresses the uses and
benefits portion of Factor 1. Criterion 2 addresses the commercial demand portion of Factor
1.
4.2.2.1 Criterion 1 - Utility
The terms "use" and "benefit" have similar connotations but distinct meanings. The "use"
or "purpose" is a way to describe or classify a product. Once the purpose of a product is
known, benefits can be assessed. The development of comparative measures for "use" does not
appear to be practicable. It is, however, possible to qualitatively measure or compare the
benefits derived from the use of products. Therefore, because uses can only be measured or
compared in terms of the benefits they provide, Criterion 1 addresses both uses and benefits
through application of the concept of product utility.
Criterion 1 provides a measure of the comparative utility of products. Inherent to the
utility scale is the concept of essentiality, that is, how indispensable a product is to the
consumer. Less essential products rank higher on the scale and more essential products rank
lower. The utility scale is presented below.
Criterion 1: Utility
Utilitarian Lifestyle/aesthetic
Function Function
4.2.2.2 Criterion 2 - Commercial Demand
Commercial demand can be interpreted as the amount of a product society wishes to
purchase at a specific price at a specified time. A high commercial demand and market share
may indicate that a product is valued highly by a large portion of the population, or that it has
an attractive price; a low commercial demand indicates that a product is valued to a lesser
extent, or that its price makes it less attractive. Annual dollar sales is the measure typically used
by economists to indicate commercial demand for a product.
Other indicators of commercial demand that were considered include the total volume or
weight sold, the number of units sold, and price per unit. A measure of total volume or weight
sold may indicate the relative importance of the product to consumers, as does the total annual
4-3
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dollar sales. However, products that are used in larger quantities may be given undue emphasis.
Similarly, a measure of the number of units or the price per unit may, in some cases,
indicate the relative value consumers place on a particular product. The number of units may
be a useful indicator of how widespread the demand is for a product. In general, the greater the
number of units sold, the greater the number of people that use and value a product. However,
this is not always accurate, because the number of units sold depends on the number of units that
are typically used in one year as well as the number of consumers. Furthermore, both number
of units and price per unit may merely reflect the number of applications mat can be
conveniently packaged. An additional complication in applying this factor is that for some
products, such as asphalt concrete, the meaning of a "unit" is not clear.
Initially, the EPA determined that Criterion 2 should represent the (commercial demand
of a product using total annual dollar sales of the product. This preliminary decision was based
on the consideration of total annual dollar sales as a composite measure of units purchased and
price per unit. However, some concerns were raised regarding application of this measure. The
primary point of contention was related to whether a product with high annual sales should
receive low priority for regulation (i.e., higher annual sales may indicate a highly-valued product
which should not be tampered with), or a higher priority for regulation (i.e, high annual sales
may indicate a product with high volume usage resulting in high levels of VOC emissions).
Furthermore, Criterion 2 (dollar sales) may either offset or over-emphasize Criterion 7
(magnitude of VOC emissions) depending on how the EPA applied Criterion 2. For example,
consider a product with high annual sales combined with high annual VOC emissions.
Depending on the "polarity" of Criterion 2 (dollar sales), the effect of Criterion 7 (high
emissions =» score of 5) either would be offset by Criterion 2 (high sales =» score of 1) or would
be duplicated by Criterion 2 (high sales =* score of 5). Clearly, a means of tempering this effect
was needed.
One modification of Criterion 2 was suggested by the consumer products industry. The
industry proposed that it might be better to consider commercial demand based on a proxy,
which is the apparent price consumers are willing to pay for the VOC contained in a product.
This approach could be implemented by expressing commercial demand for a product as dollar
sales per tonnage of VOC emissions. This modification was suggested again and received
general acceptance at a July 1994 meeting of the National Air Pollution Control Techniques
Advisory Committee (NAPCTAC) in Durham, North Carolina.
Criterion 2, as modified, reflects commercial demand expressed quantitatively as annual
product sales ($ thousands) divided by annual VOC emissions (tons).
4-4
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Criterion 2: Demand for
than
1,000
10,000
to
<100,000
greater
than
1,000,000
1,000
to
-------
4.4
FACTOR 3: PRODUCTS WHICH EMIT HIGHLY REACTIVE COMPOUNDS
4.4.1
Kev Terminology
Photochemical Reactivity: A compound's potential to undergo chemical reaction to form
photochemical oxidants in the atmosphere.
Highly Reactive Compound: A compound which falls within one of the ten chemical
classes identified by the EPA to be highly photocnemically reactive under most conditions.
4.4.2 Criterion 4 - Emissions of Highly Rcactjve Compounds
Tropospheric (ground level) ozone is formed through a series of complex chemical
reactions involving VOC and oxides of nitrogen (NOX) in the presence of sunlight. This
phenomenon has been subject to continuing scientific investigation since well before the mid-
1970's when the EPA adopted its present scheme of classifying compounds as reactive or
negligibly reactive for the purpose of defining VOC.
However, in order to address the statutory requirement to consider relative reactivity in
developing criteria for regulating consumer and commercial products, the EPA developed a list
of 9 classes of compounds that are considered to be highly reactive under most conditions. A
discussion of photochemical reactivity and rationale for the list of highly reactive compounds is
presented in Chapter 3. Table 4-2 presents EPA's list of highly reactive compounds.
Criterion 4 places higher priority for regulation on those products which emit highly
reactive compounds. A score of 5 (higher priority) is assigned to products; which emit greater
than 1,000 tons per year of one or more highly reactive compounds in ozone nonattainment
areas. A product whose emissions of highly reactive compounds are less titan one ton per year
receives a score of 1 (lower priority). A product for which the magnitude of emissions of highly
reactive compounds is unknown receives a score of 1.
Criterion 4: Emissions of Highly Reactive Compounds fTons/vrt
than
1
1
to
10
to
<100
gr«at«r
than
1,000
100
to
-------
TABLE 4-2
CLASSES OF "HIGHLY REACTIVE11 COMPOUNDS3
Nitrites
C < 8-Alkyl-amines
Unsaturated Esters
Furan
C<6-Aldehydes
C<14-Poly-substituted Napthalenes
Alkyl-Styrenes
Polyalkyl-benzenes
C<10-Olefins
Alkyl-phenols
4-7
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4.5 FACTOR 4: AVAILABILITY OF ALTERNATIVES
This factor pertains to available, lower- VOC-emitting products and product reformulations.
The language in §183(e)(2)(B)(v), "...available alternatives at comparable cost," implies that
consideration is to be given to products on the market or developed to such a degree that
alternatives are of reasonably acceptable efficacy and have no adverse health, safety, or
environmental impacts.
4.5.1 Key Terminology
Alternative: Something that performs the same function. Alternatives include
reformulated products and substitute products and/or processes.
Comparable costs considering health, safety, and environmental impacts: At this
point, the EPA does not have information on the cost of alternative products. Until more
information becomes available, the EPA has adopted consumer acceptance as a surrogate
measure of cost comparability. Consumer acceptance of consumer products will be determined
based on 1990 market share derived from the results of the EPA's 1993 census survey of
consumer product manufacturers discussed in Sections 2.1 and 5.3. If cost information becomes
available, the EPA will include such costs in its consideration of the availability of alternatives
and the priority for regulation. Furthermore, cost of alternatives will be considered as part of
the rulemaking process for categories listed for regulation under §183(e).
Consumer acceptance: A product commands a "significant" market share. The market
percentage which constitutes a significant market share will vary for each product category. For
example, within a product category containing a great number of products, a small share of that
market may be considered significant. Conversely, the same small share of a category
containing few products may not be significant.
Reformulated Product: A product with the same form and function, but with one or
more ingredients changed to achieve lower VOC emissions.
Substitute: A product of a different form with lower VOC emissions, but that retains the
same function as the original product. A substitute can also be an alternative process or method
of application that performs the same function as the original process but results in reduced VOC
emissions (e.g., brush-on application of paint substituted for aerosol spray painting; high-
volume, low-pressure spray application substituted for conventional spray application; etc.).
4.5.2 Criterion 5 - Availability of Alternatives
This criterion considers both substitutes and reformulated product!! that are currently
available. Information on VOC emissions and relative market shares, available from product
category studies and from the inventory, is used to identify available substitutes and/or lower
VOC formulations. In assessing the availability of acceptable alternatives,, all known impacts
(e.g., product efficacy, health and safety, environmental impacts) are considered.
4-8
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In developing Criterion 5, the EPA recognized that there is a "hierarchy of control
measures" in which some measures are believed to be more onerous than others. Specifically,
reformulation is viewed as less onerous than substitution (i.e. product prohibition). Accordingly,
available reformulation at comparable cost warrants a higher priority for regulation than does
; available substitution at comparable cost. The difference in priority between reformulation and
substitution is not meant to imply that reformulation is more cost-effective than substitution (the
issue of cost-effectiveness is addressed under Factor 5, Section 4.6). Rather, the EPA believes
that because reformulation involves alternatives within the same product form and market
channels, it is therefore less disruptive to the affected industry and to the consumer. Since
substitution involves replacing entire product forms through product prohibition, the potential
exists for greater economic dislocation. While possibly causing no net loss in sales or
employment across the industry, substitution may reduce demand for certain products while
increasing demand for others.
Based on this "hierarchy of control measures," the scale for Criterion 5 assigns the lowest
score (lower priority for regulation) to those products for which no known alternatives exist.
The highest score (higher priority) is assigned to products for which reformulation is possible
(i.e., a lower-VOC product is available, is accepted by the consumer as indicated by a
significant market share, and has comparable efficacy, health effects, and environmental
impacts). Products for which insufficient data exists to make this determination are assigned a
mid-range (neutral) score. The scoring partitions for Criterion 5 are presented below.
Criterion 5: Availability of Alternatives
No available
alternatives
at any cost
Insufficient
data available
on alternatives
Reformulation
available at
comparable cost
Reformulation or
substitution
available, but not
at comparable cost
Substitution
available at
comparable cost
4.6
FACTORS: COST-EFFECTIVENESS OF CONTROLS
4.6.1
Kev Terminology
Control: Measure applied to eliminate or reduce VOC emissions to the ambient air.
4-9
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Best Available Controls: "...equipment, measures, processes, methods, systems or
techniques, including chemical reformulation, product or feedstock substitution, repackaging,
and directions for use, consumption, storage, or disposal." [§183(e)(l)(A>]
Cost-effectiveness: Unit cost per unit of benefit; cost of control per unit of VOC
reduction ($/ton). Most cost-effective means the least cost per ton of VOC reduction.
4.6.2
Criterion 6 - Cost-Effectiveness of Controls
Each product category receives a score of 1 to 5 based on application of one of two
possible rating methods. Categories for which the cost-effectiveness value is known are assigned
a score using Method 1. Categories for which cost-effectiveness data are unavailable are
evaluated by implementing Method 2. Each product or product category will be evaluated using
either Method 1 QI Method 2 as determined by the availability of cost-effectiveness data.
4.6.2.1 Method 1 (Known Cost-Effectiveness Value)
In using Method 1, categories for which the cost of control is very high receive a 1 (low
priority). Categories for which controls are very cost-effective are assigned a 5 (high priority).
Criterion 6: Cost-Effectiveness of Controls (Method 11
Cost per
ton of VOC
removed is
greater
than 2 X
Cost per
ton of VOC
removed
is
>0.5 Z to X
Cost per
ton of VOC
removed is
less than
0.25 X
Cost per
ton of VOC
removed is
>X to 2 X
Cost per
ton of VOC
removed is
0.25 X
to
0.5 X
Where X is equal to $2,000, the existing
emissions.
^-accepted cost-effectiveness value for VOC
4.6.2.2 Method 2 (Cost-effectiveness Value Unknown)
For categories for which cost-effectiveness data are unavailable, scores are assigned by
considering a category's (1) annual VOC emissions and (2) available control alternatives. How
each of these considerations may help predict cost-effectiveness of controls is discussed below.
4-10
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(1)
Annual VOC Emissions
Even without much information about a given category, one would expect that greater
emission reductions could be achieved for a category with a larger magnitude of uncontrolled
emissions. Accordingly, controls for a category with high VOC emissions would tend to be
more cost-effective and would warrant a higher priority for regulation.
(2) Availability of Alternatives
As explained in Section 4.S.2, EPA has adopted a "hierarchy of control measures" in
which some measures are believed to be more onerous than others. A category for which
control measures are least onerous (e.g., reformulation) would warrant a higher priority for
regulation than a category for which the available controls are more onerous (e.g., product
substitution).
Combining (1) and (2} to Obtain a Score
The score for Criterion 6 is obtained by combining the two above considerations by
employing a matrix which incorporates magnitude of emissions (Criterion 7) as the Y-axis and
availability of alternatives (Criterion 5) as the X-axis. The highest score (higher priority) is
assigned to a product with high annual emissions (Criterion 7 = 5) and for which reformulation
is available at comparable cost (Criterion 5=5). The lowest score (lower priority) is assigned
to a product with low annual emissions (Criterion 7 = 1) and for which there is no available
alternative (Criterion 5 = 1).
Criterion 6: Cost-Effectiveness of Controls (Method 2}
Criterion
7 Score
(Emissions)
5
4
3
2
1
Criterion 5 Score (Availability of Alternatives)
< Reformulation Available No Available Alternatives >
5
5
4
4
3
3
4
4
4
3
3
2
3
4
3
3
2
2
2
3
3
2
2
1
1
3
2
2
1
1
4.7 ADDITIONAL CONSIDERATIONS
Section 183(e) states that the EPA must consider the five factors listed, but does not limit
the EPA's discretion to consider other relevant factors. Two additional considerations were
identified by the EPA and are discussed in the following sections.
4-11
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4.7.1 Criterion 7 - Mgnitude of
VOC
Criterion 7 does not specifically address any of the five factors listed in §183(e).
However the EPA believes magnitude of emissions to be an important consideration. Products
with greater VOC emissions would be tend to be targeted for earlier regulation, and would be
assigned a high score. The scoring partitions are presented below.
Criterion 7: Magnitude of Annual VOC Emissions
!••*
than
100
1,000
to
<10,000
gr«at«r
than
100,000
100
to
-------
The output of the numerical scoring exercise will be a list of all categories within the
broad scope of §183(e) ranked by numerical scores assigned through application of Criteria 1
through 7. The list of product categories which will be scheduled for regulation under §183(e)
will be a subset of the categories scored. Actual selection of categories for regulation and
placement of these categories in the four groups will be performed based on consideration of
Criterion 8 (Regulatory Efficiency) which was introduced in Section 4.7.
The approach for exercising Criterion 8 to place categories in Groups I-IV for regulation
includes several considerations. A primary consideration will be to list those product categories
that account for at least 80 percent of baseline VOC emissions, on a reactivity-adjusted basis,
in ozone nonattainment areas. An effort will be made to adhere to the numerical ranking
scheme, but the EPA is prepared to override the numerical ranking based on program
considerations. Furthermore, consideration will be given to listing for early regulation those
categories affected by ongoing rule or control techniques guideline (CTG) development.
The initial publication of the list and schedule for regulations will not be considered final
Agency action. Accordingly, Groups I-IV may be modified such that a product category may
be moved to a different group, delisted altogether, or added to the list. The EPA will make
appropriate adjustments to ensure that we continue meet the statutory requirements of §183(e)
to regulate categories which account for at least 80 percent of baseline emissions. With respect
to the priority for regulation assigned to each product, the EPA will consider public comments
at the time each product is considered for regulation in a rulemaking process.
4.9 REFERENCES
1. Letter from R. Engel, Chemical Specialties Manufacturers Association, to B. Jordan,
U.S. Environmental Protection Agency, August 31, 1993. Comments on draft criteria.
2. U.S. Environmental Protection Agency, Requirements for Preparation, Adoption, and
Submittal of Implementation Plans; Approval and Promulgation of Implementation Plans,
Federal Register. 57 FR 3941, February 3, 1992.
3. Dimitriades, B., Scientific Bases of the VOC Reactivity Issues Raised by Section 183(e)
of the Clean Air Act Amendments of 1990, U.S. Environmental Protection Agency, Office
of Research and Development, Atmospheric Research and Exposure Assessment
Laboratory, Research Triangle Park, North Carolina, 1994.
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CHAPTER 5
COMPREHENSIVE EMISSIONS INVENTORY
This chapter presents a detailed summary of the EPA's inventory of VOC emissions from
consumer and commercial products. The purpose of the inventory effort was to develop
estimates of annual VOC emissions in ozone nonattainment areas for every consumer and
commercial product category subject to §183(e). These estimates, along with other information,
were used to develop a prioritized list of categories to be regulated as required by §183(e).
Eight criteria for regulating consumer and commercial products were developed based on the
factors listed in §183(e). Three of these criteria (emissions of highly reactive compounds,
availability of lower-VOC alternatives, and annual VOC emissions) were evaluated based on the
inventory data. These criteria are discussed in detail in Chapter 4. The emission estimates and
per capita emission factors developed by the EPA can also be used by State and local agencies
in developing emission inventories for specific mixes of products and categories within their
jurisdiction.
5.1 ELEMENTS OF THE INVENTORY
Because of the wide variety of products subject to §183(e), emission estimates were
developed independently for three major subdivisions of the universe of consumer and
commercial products.
5.1.1 Consumer Products (including commercial and institutional uses)
These are products which most people associate with the term "consumer products." This
group includes such products as personal care products, household cleaning products, household
pesticides, automotive maintenance and detailing products, and many others. Institutional and
commercial uses of these or similar products are also considered within the scope of traditional
consumer products. Emission estimates for these categories were obtained through a 1993
census survey of consumer product manufacturers. This segment of the inventory is summarized
in Section 5.3.
5.1.2 Industrial Products Affected by Existing Federal Regulatory Programs
The statutory definition of "consumer or commercial product" is much broader than just
the traditional consumer products and includes virtually all VOC-emitting products used in the
home, by businesses, by institutions, and in industrial manufacturing operations. This segment
of the consumer and commercial products inventory includes those products which are used
industrially and are affected by existing or ongoing regulations developed by the EPA and/or by
the States. These products include a wide range of surface coatings, metal cleaning solvents,
adhesives, inks, agricultural pesticides, asphalt paving materials, and a host of others. Estimates
of VOC emissions from these products were obtained from background documentation developed
for the respective regulations or guidance documents. Emission estimates for previously
regulated categories are based on "residual" emissions (i.e., emissions which continue after
controls have been applied). Estimates for categories associated with ongoing standards
5-1
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development are 1990 "baseline" emission estimates from those categories (i.e, emissions before
any controls have been applied). This segment of the inventory is summarized in Section 5.4.
5.1.3 Products Addressed bv Special Studies
Many consumer and commercial products fall outside the scope of the consumer products
survey and the categories affected by existing or ongoing regulatory programs. This third
segment of the inventory is comprised of products which do not fall within the first two
segments. It includes such products as foods, beverages, and tobacco; small combustion sources
such as kerosene heaters, camp stoves, and artificial fireplace logs; products used in the roofing
and textile industries; and a wide range of miscellaneous products including but not limited to,
mold release agents, automotive parts washers, and products used in the manufacture of
fiberglass boats. Emission estimates for these products were obtained through special studies
conducted by the EPA. These studies were limited to searches of the literature for relevant
scientific investigations in which VOC emissions from these products were characterized and
quantified. This segment of the inventory is summarized in Section 5.5.
5.2 ADJUSTMENTS TO INVENTORY DATA
In accordance with §183(e), an effort was undertaken to develop estimates of VOC
emissions from consumer and commercial products in ozone nonattainment areas. Because the
"raw" data from the consumer products survey and the other sources were primarily for
nationwide mass emissions based on the VOC content of the products, the following factors were
considered in an effort to develop realistic estimates which could be used to satisfy the
requirements of §183(e).
5.2.1 Adjustments for Fate of VOC in Landfills and in Wastewater
Historically, inventories of VOC emissions from consumer and commercial products have
been based on the assumption that all VOC contained in these products eventually volatilize,
enter the ambient air, and are thus available to react to form ozone. However, the VOC in some
products such as soaps, laundry detergents, household cleaners, mouthwashes, disinfectants, etc.
may be combined with water during and/or following use and enter the wastewater stream. In
order to ensure that the inventory results reflected actual VOC emissions rather than VOC
content, the EPA initiated an investigation to identify information on the fate of consumer
product VOC that enter the wastewater stream. This study is summarized in Chapter 6. Based
on this information, and information provided by the major consumer product industry trade
associations 1»2,3,4,5) f^j emission estimates for several product categories reported in this
inventory (primarily household cleaning and laundry products) reflect a "percent VOC content
emitted" of somewhat less than 100 percent.
Another area of concern was that it may be possible for a portion of the unused product
(and VOC content) to remain in the container packaging following disposal in landfills. A study
was undertaken by EPA to determine whether some adjustment of the emission estimates should
be made to account for this phenomenon. Based on the study, also summarized in Chapter 6,
the EPA determined that, because of the scarcity of information and the variability of landfill
operating procedures, it was not possible to adjust the emission estimates to account for fate of
5-2
-------
the VOC in landfills. Consequently, for the purpose of this inventory study, the assumption was
made that any remaining VOC content in the disposed products is eventually emitted to the air.
> •-,- ?t * r
5.2.2 Adjustment to Reflect Emissions in Ozone Nonaittfliff>t!Kff?t AIW
Section 183(e) primarily focuses on VOC emissions in ozone nonattainment areas.
Because much of the emissions data collected reflects nationwide emissions, some adjustment
was necessary to obtain estimates for nonattainment areas. Since emissions from traditional
consumer products are roughly proportional to population, the nationwide estimates from the
consumer products survey were scaled down based on the distribution of population in ozone
nonattainment areas. In 1990, approximately 148 million of the 248 million persons in the U.S.
resided in ozone nonattainment areas (S9.7 percent). Based on this distribution, the nationwide
emission estimates for traditional consumer products weie multiplied by a factor of 0.6 to reflect
emissions in nonattainment areas.
For many categories of industrial products, estimates were developed based on actual
locations of emission sources. Consequently, nonattainment area emission estimates were
developed for those products directly. For any categories for which specific locations of
emission sources were unknown, the population scaling method discussed above was employed.
5.2.3 Adjustment for Photochemical Reactivity
Section 183(e)(3)(A) requires the EPA to "list those categories of consumer or commercial
products that the Administrator determines, based on the study, account for at least 80 percent
of the VOC emissions, on a reactivity-adjusted basis, from consumer and commercial products
in areas that violate the NAAQS for ozone." The inventory study was directed toward
developing estimates of mass VOC emissions in ozone nonattainment areas. Consequently, the
relative photochemical reactivities of individual species were not applied to the inventory data
until later. The methodology followed by the EPA to adjust the emission estimates for purposes
of establishing the "80-percent list" is presented in Chapter 3. Application of the adjustment
methodology and the preliminary category ranking which resulted is discussed in detail in
Section 4.8.
5.3 CONSUMER PRODUCTS SURVEY
One important segment of the inventory of VOC from consumer and commercial products
are the "traditional consumer products" described in Section 5.1.1. In order to develop an
accurate, reliable emission estimate for this segment, the EPA and the consumer products
industry undertook a massive effort to assemble accurate formulation and sales information for
over 24,000 individual consumer products. The following sections describe the survey process
and the results obtained from that effort.
5.3.1 Development of the Survey Approach and Queytjoftnajre,
In anticipation of the Clean Air Act Amendments, the EPA conducted a symposium in
November 1989 on regulatory approaches for reducing VOC emissions from the use of consumer
products. The purpose of the symposium was to initiate a dialogue among the EPA, the States,
5-3
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and industry toward working cooperatively in addressing this source of emissions.
Approximately 100 companies and trade associations participated in the symposium. State
environmental agencies from California, Michigan, New Jersey, New York, North Carolina,
Texas, and Virginia were represented as well. The proceedings of that symposium were
documented in an EPA report (EPA-450/3-90-008, January 1990).
One of the key issues raised by industry representatives at the symposium was the lack of
a reliable, speciated inventory of VOC emissions from traditional consumer products. The
industry demanded that the EPA employ a census survey of consumer product manufacturers and
distributors to develop such an inventory.
In November of 1990 the EPA and the Cosmetics, Toiletries, and Fragrances Association
(CTFA) met twice with the Chemical Specialties Manufacturers Association (CSMA) at CSMA's
headquarters in Washington, D.C. to discuss the plan for developing the inventory. It was
suggested that the best approach for a number of consumer product categories would be through
a survey of the manufacturers of those products. Information for this consumer products survey
would be collected by the EPA via questionnaires distributed under the authority of Section 114
of the CAA. This approach was suggested by the consumer products industry, specifically the
CSMA.
Refinements to the survey approach were made over the next two years by the work group
consisting of EPA, CSMA, CTFA, the Soap and Detergent Association (SDA), other trade
associations, and representatives of several companies (L&F Products, Sherwin-Williams,
Procter & Gamble, Drackett, Gillette, S.C. Johnson Wax, United Industries, Aeropres
Corporation, CCL Custom Manufacturing, Helene Curtis, and Carter-Wallace). This work
group met on several occasions to develop a joint protocol for the consumer products inventory
effort.
In December 1991, the survey questionnaire developed by the work group was sent to nine
volunteer test respondents. The responses from this test were analyzed and the results presented
at a March 1992 meeting of the work group. Revisions to the questionnaire were made and sent
to the work group members for final endorsement.
It was recognized early in the planning of the survey that, due to the large number of
survey questionnaires necessary, Office of Management and Budget (OMB) approval would be
required through the submission of an information collection request (ICR). The CSMA offered
to endorse the ICR and state that the industry and EPA reached a consensus that the Section 114
approach was the most suitable vehicle for gathering the required information. The ICR was
submitted to OMB in July 1992, and approval was granted by OMB in December 1992.
5.3.2 Response to the Survey
The total number of questionnaires mailed was 3,610; however, a number of companies
had responses from more than one division and some companies forwarded copies to companies
mat were not on the original mailing list. These additional sources of survey responses brought
the total number of questionnaires being tracked to 3,802.
5-4
-------
Out of the 3,802 survey questionnaires accounted for in the tracking system, only 1,283
questionnaires (approximately one-third) are included in the No Response category. An
additional 352 (9.3 percent) were returned as undeliverable by the U.S. Postal Service.
Approximately one-quarter of the survey questionnaires were responded to by the company
indicating that they did not manufacture, distribute, or sell any of the products found in one of
the product categories (Company Sheet Only). Responses via either product sheets or data
diskettes were provided by the remaining companies. Thirty responses (0.8 percent) were
obviously inappropriate and could not be used in the survey without lengthy follow-up. The
remaining responses were complete with product information. An additional 35 completed
responses were provided for a company by a third party (e.g. .consulting firm, custom packager,
etc.). There were, therefore, 1,173 complete responses (including product formulation data)
from companies manufacturing consumer and commercial products.
Not all of the 1,173 complete responses, however, could be used in the final analysis. A
number of problems were encountered when the information was attempted to be entered into
the data entry system from both hard copy product sheets and data diskette submissions. In all
cases, attempts were made to contact the company when problems were identified, but these
attempts were not always successful. In many cases, information vital to the project was not
provided, such as the pounds of product sold in 1990. In a number of other cases, products
were inappropriately grouped (i.e., products from more than one category were reported
together). These problems and a number of others were not resolved and 96 such responses
were not included in the final data set. Therefore, the final data set included 1,077 complete
responses.
5.3.3 Information Obtained from the Survey
Consumer products often contain ingredients which are of extremely low volatility (i.e.,
some ingredients evaporate at such a low rate that they do not enter the air to any appreciable
degree). These low-volatility ingredients include surfactants used in shampoos and laundry
detergents, heavy oils used in lubricants, and waxes used in lip balms and underarm
antiperspirants. Furthermore, if volatility is not considered, many consumer products contain
100 percent VOC by definition6 even though portions of their contents do not become available
to react with NOX in the atmosphere to form ozone. This phenomenon would severely hinder
efforts to evaluate products with to regard to availability of lower VOC alternatives, since in
some cases all the products in a category (even the ones which don't enter the air) may be of
equal VOC content. The EPA recognized this problem and examined the possibility of
collecting information only on ingredients which readily enter the air.
Consequently, the EPA adopted a volatility threshold which applies to ingredients reported
in the survey. For purposes of the survey, the term "reportable VOC" (RVOC) was coined to
indicate ingredients to be reported through the survey. The term RVOC includes a subset of
compounds defined by the EPA to be VOC and is not to be construed as a modification of the
5-5
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EPA's definition6. A consumer product ingredient is an RVOC if it is a VOC by EPA's
definition and meets one of the following criteria:
1. The ingredient compound exists as a solid at room temperature: (20°C) but readily
sublimes (becomes a vapor at room temperature). Examples include para-
dichlorobenzene, naphthalene, and camphor.
2. The ingredient compound exists as a solid at room temperature (20°C) but becomes
a vapor at the temperature at which the product is used. Examples include
components of hot-melt glues, plug-in air fresheners, etc.
3. The ingredient compound has a vapor pressure greater than 0.1 millimeter of
mercury (mmHg) at 20°C.
4. The vapor pressure for the ingredient compound is unknown, and the compound's
empirical formula contains 12 or less carbon atoms.
Several States have adopted consumer product rules which are based on these same
volatility criteria. The status of State and local regulatory activities concerning consumer
products is discussed in Section 2.6.
Table 5-1, the principal output of the survey, presents content and emission data for each
product category surveyed. Specifically, this table provides information for each category on
(1) number of products reported; (2) product sales reported (tons); (3) RVOC content reported
(tons); (4) estimated market coverage (i.e. what percentage of the market for a particular
category was captured by the survey); (5) adjusted product sales (reported sales scaled up based
on market coverage); (6) adjusted RVOC content (reported content scaled up based on market
coverage); (7) RVOC content emitted (i.e. , the percentage of the product's RVOC content which
enters the ambient air after fate adjustments); (8) tons of RVOC emitted nationwide; (9) pounds
of RVOC emitted per 10,000 persons; and (10) RVOC emissions in ozone nonattainment areas
(tons).
Items 1, 2, and 3 were obtained directly from the survey responses. Item 4 (market
coverage) was estimated based on information furnished by CSMA, CTFA, and SDA following
their reviews of the initial results of the survey and lists of companies responding in each
category1'2'3. Adjusted product sales (item 5) and adjusted RVOC content (item 6) were
obtained by dividing reported sales and reported RVOC content by the estimated market
coverage percentage. The adjustments were made in the following manner:
_ Tonna*e top01** _ = AdjustedTonag e
Estimated Market Coverage
Percent RVOC emitted was obtained by multiplying the RVOC content by a fate
adjustment factor. The adjustment factor ranged from 1 percent to 100 percent and was based
on information supplied by CSMA, CTFA, and SDA1'2'3*4'5. The fate adjustments were made
5-6
-------
to account for products which enter the wastewater stream and subsequently biodegrade rather
than being emitted to the air. A fete adjustment factor of 100 percent means that all the RVOC
content of the product is emitted to the air. Conversely, an adjustment factor of 1 means that
only 1 percent of the RVOC are emitted.
Probably the most useful of the items in Table 5-1 are items 9 and 10. Data on emissions
in ozone nonattainment areas will be used by the EPA in determining which categories will be
targeted for regulation under §183(e). The per capita emission factors (in this case, pounds of
RVOC emitted per 10,000 persons) will enable the EPA, States, and local environmental
agencies to develop emission estimates for specific combinations of products based on
population. This is by far the most comprehensive and accurate set of emission factors ever
developed for consumer products.
In order for the EPA to assess the availability of lower-VOC alternatives, histograms were
prepared for individual product categories which show the distribution of market share (by tons
of product sold) at various levels of RVOC content. On these histograms, tons of product sold
is plotted against RVOC content levels in 5 percent increments. By examining the histograms,
the EPA can identify the distribution of high-VOC and low-VOC products and can use this
information to assess the possible emission reductions which could be obtained from a given
VOC limit. This information can also enable the EPA to determine (for a given category) to
what extent lower-VOC alternatives are accepted by consumers. Due to space limitations, these
histograms were not included in the inventory report.
Another useful output of the survey is a compilation of formulations for every product
reported. Except in the confidential files of survey responses, the formulations are not identified
by product brand name or manufacturer. To further protect the confidentiality of the
formulation data, the products are presented in descending order of RVOC content within each
category. This compilation is quite voluminous; for example, there were over 1,100 individual
formulations of aerosol spray paints reported. Consequently, these formulations could not be
included in the report, but can be used during the regulatory phase.
Another important output of the survey is information on individual chemical species
contained in consumer products. This information will allow the EPA to identify those products
which contain highly reactive compounds, compounds which are considered to be hazardous air
pollutants, and/or toxics. Speciated content data can also provide needed information to EPA
offices for use in risk assessment.
5-7
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5.4 INDUSTRIAL PRODUCTS AFFECTED BY EXISTING FEDERAL PROGRAMS
This segment of the consumer and commercial products inventory includes those products
which are used industrially and are affected by existing or ongoing regulations developed by the
EPA and/or by the States. These products include a wide range of surface coatings, metal
cleaning solvents, adhesives, inks, agricultural pesticides, asphalt paving materials, and a host
of others. Estimates of VOC emissions from these products were obtained from background
documentation developed for the respective regulations or guidance documents. Emission
estimates for previously regulated categories are based on "residual" emissions (i.e., emissions
which continue after controls have been applied). Estimates for categories associated with
ongoing standards development are 1990 "baseline" emission estimates from those categories
(i.e, emissions before any controls have been applied).
5.4.1 Emission Estimates
The purpose of this inventory study was to develop estimates of VOC emissions in ozone
nonattainment areas. Accordingly, the estimates presented in this report reflect nonattainment
area emissions. For many of the industrial products discussed in this section, estimates were
developed based on actual locations of emission sources, and include only those emissions in
nonattainment areas. For categories for which specific locations of sources; are unknown, the
scaling method discussed in Section 5.2 was used to apportion emissions based on population
distribution.
Table 5-2 presents a summary of VOC emissions in nonattainment areas attributable to
industrial products and activities subject to §183(e) for which federal regulatory programs are
existing or under development. Section 5.4.2 contains descriptions of the products and processes
listed in Table 5-2.
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TABLE 5-2
VOC EMISSIONS IN NONATTAINMENT AREAS
FOR PRODUCTS AFFECTED BY EXISTING FEDERAL
REGULATORY PROGRAMS
Category
Architect & indust maint coatings
Automobile refinishing products
Aerospace paints and coatings
Wood furniture coatings
Ship and boat coatings
Metal furniture coatings
Flat wood paneling coatings
Large appliance coatings
Magnet wire coatings
Metal can coatings
Metal coil coatings
Other metal product coatings
Auto and light truck assy coatings
Paper, film, and foil coatings
Magnetic tape coatings
Business mach plastic part coating
Automotive plastic part coatings
Flexible packaging printing
Rotogravure publication printing
Lithographic printing
Letterpress printing
Tire manufacturing cements
Miscellaneous industrial adhesives
Nonattainment
Emissions
(tons/yr)
315,000 a
55,000 a
107,500
60,000
15,100
63,000 a
20,000 a
15,600 a
4,800 a
45,000 a
21,600 a
218,400 a
75,000
65,000
5,500
5,500
16,500
150,000
20,000
600,000
28,200 a
26,400 a
201, 600 a
Year
of
Estim
1990
1990
1990
1990
1990
1985
1985
1985
1985
1985
1985
1985
1990
1985
1990
1990
1990
1990
1990
1990
1985
1985
1985
Ref
7
8
9
10
11
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
Federal
Control
Measure
B^
A, Bb
Mb, Cb
Mb, Cb
A, M5, Cb
C, N
C
C, N
C
C, N
C, N
C
C, N
C
C, N, M
Cb, N
Cb
C, Mb
C, N, M6
A
C, N
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TABLE 5-2 (Continued)
VOC EMISSIONS IN NONATTAINMENT AREAS
FOR PRODUCTS AFFECTED BY EXISTING FEDERAL
REGULATORY PROGRAMS
Category
Metal cleaning (degreasing)
Industrial cleaning solvents
Petroleum drycleaning solvents
Agricultural pesticides
Cutback asphalt paving materials
Synthetic fiber spinning solvents
Fabric coating
Fabric printing
TOTAL FOR THIS TABLE
Nonattainment
Emissions
(tons/yr)
36,000
150,000 a
54,600 a
15,000 a
128,400 a
46,200 a
21,000 a
25,200 a
2,611,100
Year
of
Estim
1990
1990
1985
1987
1985
1985
1985
1985
Ref
12
13
12
14
12
12
12
12
Federal
Control
Measure
C, N, M
A
C, N
A
C
N
C, N
Nonattainment area emission estimates were obtained by adjusting nationwide estimates according to the
distribution of nationwide population in nonattainment areas in 1990. Estimates for categories without this
footnote were developed for nonattainment areas and needed no adjustment.
148 million (nonattainrnent areas)
248 million (nationwide)
59.68%
60%
b Document or regulation currently being developed
A Alternative Control Techniques Document (ACT)
B Regulation requiring Best Available Controls under |183(e)
C Control Techniques Guidelines Document (CTG)
M Maximum Achievable Control Technology (MACT) Standard
N New Source Performance Standards (NSPS)
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5.4.1 Architectural and Industrial Maintenance Coatings
The U.S. architectural and industrial maintenance (AIM) coating industry is composed of
roughly 500 manufacturers. This wide array of AIM coatings are used by do-it-yourself,
professional, and industrial painters. These coatings include house paints, wood finishes, cement
coatings, roof coatings, traffic paints, and industrial maintenance coatings. For purposes of
regulation, AIM coatings have been further classified into numerous coating categories. These
categories include:
Alkali Resistant Primers
Anti-fouling Coatings
Bituminous Coatings & Mastics
Chalkboard Resurfacers
Concrete Protective Coatings
Extreme High Durability Coatings
Flat Coatings
Flow Coatings
Graphic Arts Coatings
High Temperature Coatings
Industrial Maintenance (I/M) Coatings
Lacquer Stains
Mastic Texture Coatings
Multi-Color Coatings
Nuclear Power Plant Coatings
Pre-Treatment Wash Primers
Quick Dry Coatings
Roof Coatings
Sanding Sealers
Shellacs
Swimming Pool Coatings
Traffic Marking Paints
Waterproofing Sealers
5.4.2 Automobile Refmishing Products
Antenna Coatings
Anti-Graffiti Coatings
Bond Breakers
Concrete Curing Compounds
Dry Fog Coatings
Fire-Retardant/Resistive Coatings
Floor Coatings
Form Release Compounds
Heat Reactive Coatings
Impacted Immersion Coatings
Lacquers
Magnesite Cement Coatings
Metallic Pigmented Coatings
Non-Flat Coatings
Ornamental Metal Lacquers
Primers and Undercoaters
Repair/Maint Thermoplastic Coatings
Rust Preventative Coatings
Sealers
Stains
Thermoplastic Rubber Coatings
Varnishes
Wood Preservatives
The steps involved in automobile refinishing include surface preparation, coating
application, and spray equipment cleaning. Each of these steps can be a source of VOC
emissions. Emissions can be reduced by using waterborne surface preparation products, and by
using coatings that are inherently low in VOC, such as urethanes. Emissions could also be
reduced by reformulating conventional coatings to lower their VOC content. Improved transfer
efficiency reduces VOC emissions by decreasing the amount of coating overspray. Gun cleaning
equipment that controls evaporative losses also recirculates solvent for several cleanings to
reduce solvent use.
Gun cleaning is a source of solvent emissions. Spray equipment can be cleaned manually
with little to no control of evaporative emissions or with gun cleaning equipment designed to
reduce solvent consumption, evaporation, and worker exposure. Solvent may be emitted from
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gun cleaning equipment both during actual cleaning operation (active losses) and during standby
(passive losses). An estimated 60 percent reduction in VOC emissions is achieved by shops that
switch from cleaning guns manually to a gun cleaner.
5.4.3 Aerospace Coatings
The most common coatings used are die broad categories of non-specialized primers and
topcoats. There are also numerous specialty coatings ranging from temporary protective coatings
to radiation effect coatings designed to shield aircraft from radar detection. Coatings are applied
to aerospace vehicles and components using several methods of application. The methods most
commonly used are spraying, brushing, rolling, flow coating, and dipping. Spray application
systems include conventional air spray, airless spray, air-assisted airless, electrostatic, and high
volume low pressure spray. Emissions from coating applications occur from 'the evaporation of
the solvents during mixing, application, drying, and overspray.
5.4.4 Wood Furniture Coatings 10
Wood furniture coatings are used in the manufacture of furniture. Adhesives are used in
assembling furniture components, in laminating veneers, and in installing upholstery. Solvents
are used to thin coatings, to remove coatings from furniture that did not meet specifications, and
to clean equipment.
Formaldehyde may be emitted from conversion varnishes, a type of coating used to finish
kitchen cabinets and some office furniture. Styrene may be emitted from some ultraviolet light
cured coatings and polyester coatings.
5.4.5 Ship and Boat Coatings ^
Emissions from shipyard operations are primarily VOC emissions that result from painting
operations. Emissions of VOC from painting operations result in three components: (1) organic
solvent in the paint "as supplied" by the paint manufacturer, (2) organic solvent in the thinner,
which is added to the paint prior to application and becomes part of the paint "as applied", and
(3) any additional volatile organic released during the cure. The organic solvents from both
components are emitted as the applied paint dries/cures. This organic solvent portion of a paint
is composed of a mixture of different solvents that perform either of two equally important
functions: (1) reduce viscosity so the paint can be atomized as it leaves the spray gun, or (2)
provide essential surface characteristics of the paint once it is applied. Solvents used for
atomization typically have low boiling points and flash to a vapor upon leaving the spray gun.
These solvents evaporate relatively quickly during initial drying to prevent excessive flow.
Solvents responsible for imparting the desired surface characteristics must have higher boiling
points and subsequently evaporate more slowly man atomizing solvents to allow sufficient
leveling and adhesion. Of the solvents used in marine paints, most are VOC.
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5.4.6 Metal Furniture Coatings 1A
Metal furniture coating consists of the application of prime and top coatings to any piece
of metal furniture or metal part included in the categories of household furniture, office
tfumiture, public building and related furniture, and partitions and fixtures. Typically, the metal
i substrate is first cleaned, rinsed in a phosphate bath, and oven-dried to improve coating
.adhesion. If a prime coat is necessary, the part may be dipped, sprayed, or flow coated and
then dried in a curing oven. Subsequent topcoats, or in the event no prime is required, the
single topcoat is usually by spray. The freshly coated parts are conveyed to the oven through
a flash-off tunnel during which the coating "flows out" to a uniform thickness and some of the
solvent evaporates. The parts are baked in single or multi-pass ovens at 15Q-230°C.
Specific emission sources on the coating line are the coating application, the flash-off area,
and the bake oven. On the average conveyorized spray coating line, it is estimates that about
40 percent of the total VOC emissions come from the application station, 30 percent from the
flash-off area, and 30 percent from the bake oven. In addition, fugitive emissions also occur
during mixing and transfer of coatings.
5.4.7 Flat Wood Paneling Coatings ^
A typical flat wood coating facility applies stains and varnishes to natural plywood panels
used for wall coverings. Other plants print wood grain patterns on particle board panels that
were first undercoated with an opaque coating to mask the original surface. Coatings applied
to flat wood paneling include fillers, sealers, "groove" coats, primers, stains, basecoats, inks,
and topcoats. Most coatings are applied by direct roll coating. Filler is usually applied by
reverse roll coating. The offset rotogravure process is used where the coating and printing
.operation requires precision printing techniques. Other coating methods include spray
'techniques, brush coating, and curtain coating. A typical flat wood paneling coating line
includes a succession of coating operations. Each individual operation consists of the application
of one or more coatings followed by a heated oven to cure the coatings.
Emission of VOC from a flat wood coating occurs primarily at the coating line, although
some emissions also occur at pain mixing and storage areas. All solvent that is not recovered
can be considered a potential emission.
5.4.8 Large Appliance Coatings
Large appliance products include kitchen ranges, ovens, microwave ovens, refrigerators,
freezers, washers, dryers, dishwashers, water heaters, and trash compactors. A "large appliance
surface-coating line" consists of the coating operations for a single assembly line within an
appliance assembly plant. Typically, the metal substrate is first cleaned, rinsed in a phosphate
bath, and oven dried to improve coating adhesion. If a prime coat is necessary, the part may
be dipped, sprayed, or flow-coated and dried in a curing oven. Subsequently, the topcoat is
applied, usually by spray. The fresh coated parts are conveyed through a flash-off tunnel to
evaporate solvent and cause the coating to flow our properly. After coating and flash-off, the
parts are baked in single or multipass ovens at 150-230°C. Major emissions occur at the
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application (spray booth) area, flash-off area, and the curing oven. Fugitive emissions occur
during mixing of coatings.
5.4.9 Maenet Wire Coatings
12
Magnet wire coating is the process of applying a coating of electrically insulating varnish
or enamel to aluminum or copper wire for use in electrical machinery. The uncoated wire is
unwound from spools and passed through an annealing furnace to mate the wire more pliable
and to burn off oil and dirt left from previous operations. The wire passes from the furnace to
the coating applicator. At a typical applicator, the wire acquires a thick coating by passage
through a coating bath. The wire is then drawn vertically through an orifice or coating die
which scrapes off excess coating and leaves a film of the desired thickness. The wire is routed
from the coating die into an oven where the coating is dried and cured. A typical oven has two
zones. The wire enters the drying zone, held at 200°C, and exits through the curing zone, held
at 430°C. A wire may pass repeatedly through the coating applicator and oven to build a
multilayered coating. After the final pass through the oven, the wire is rewound on a spool for
shipment. There are approximately 30 plants nationwide which coat magnet wire.
The oven exhaust is the most important emission source in the wire coating process.
Solvent emissions from the applicator are low due to the dip coating technique.
5.4.10 Metal Can Coatings ^
The coatings used depend on the type of can and the type of product to be packed in the
can. A "three-piece" can is made from a cylindrical body and two end pieces. A large metal
sheet is first roll coated with both an exterior and an interior coatings, then cut to size, rolled
into a cylinder (body) and sealed at the side seam. A bottom end piece formed from coated
metal is then attached to the body. The can interior may then be spray coated before the can
is filled with a product and sealed with the top end piece. A "two-piece can body and bottom
is drawn and wall ironed from a single shallow cup. After the can is formed, exterior and
interior coatings are applied by roll coating and spraying techniques, respectively. The can is
then filled with product and the top end piece is attached.
Solvent emissions from can coating operations occur from the application area, flash-off
area, and the curing/drying oven. Emissions vary with production rate, VOC content of coatings
used, and other factors.
5.4.11 Metal Coil Coatings 12
The metal coil coating industry applies coatings to metal sheets or strips that come in rolls
or coils. The metal strip is uncoiled at the beginning of the coating line, cleaned, and then
pretreated to promote adhesion of the coating to the metal surface. When the coil reaches the
coating application station, a coating is applied, usually by rollers, to one or both sides of the
metal strip. Some coil coatings are applied by electrodeposition. The strip then passes through
an oven to cure the coating and is then water or air quenched.
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Approximately 90 percent of the total VOC content of the coating evaporates in the curing
ovens. Of the remaining 10 percent, about 8 percent evaporates at the applicator station and 2
percent at the quench station. The rate at which VOC emissions occur is determined by the
operating parameters of the line, including: (1) the width of the metal strip, (2) the VOC and
solids content of the coating, (3) the speed at which the strip is processed, (4) the thickness at
which the coating is applied, and (5) whetliei emission abatement equipment has been installed.
5.4.12 Other Metal Product Coatings ^
The original equipment manufacturers discussed here have been referred to by a variety
of names, including coaters of miscellaneous metal parts. The category includes hundreds of
small- and medium-sized industries and their companies which coat metal parts for which more
specific regulatory guidance was not published as part of the guideline series (i.e., can, coil,
wire, automobile and light-duty truck, metal furniture, and large appliances).
Organic emissions from coating miscellaneous metal parts and products are emitted from
the application, flash-off area, and the bake oven (if used). The bulk of VOC emitted by lines
which spray or flow coat, evaporates from the application and flash-off areas. For dip-coating
operations, the bulk of the VOC is emitted from the flash-off area and bake oven. Fugitive
.emissions also occur during mixing and transfer of coatings.
5.4.13 Auto and Light Truck Assembly Coatings ^
The automobile and light-duty (less than 8,500 pounds gross vehicle weight) truck
assembly industry receives parts from a variety of sources and produces finished vehicles ready
for sale to vehicle dealers. The automobile and light-duty truck coating process is a multistep
operation performed on an assembly line producing up to 90 units per hour. There were about
;65 automobile or light-duty truck assembly plants in the United States in 1984.
Body surfaces to be coated are cleaned with various materials which may include solvents
to remove oil and grease. Then a phosphaling process prepares the surface for the prime coat.
The primer is applied to protect metal surfaces from corrosion and to ensure good adhesion of
the topcoat. Primer may be solvent-based or waterborne. Solvent-based primer is applied by
a combination of manual and automatic spraying, flow coat or dip processes. Waterborne
primer is most common now and is most v>flen applied in an electrodeposition (EDP) bath. The
prime coat is oven cured before further coating. When EDP is used to apply primer, the
resulting film may be too thin and rough to compensate for all surface defects, so a guide coat
(primer-surfacer) is usually applied and ove:i~cured before the topcoat application. Recent
developments in EDP technology produce a thicker dry film which in some cases eliminates the
need for the guide coat. On some vehicles an additional coating called a chip guard or anti-chip
primer is applied along the bottom of the ikoi s and fenders. These flexible urethane or plastisol
coatings help protect susceptible parts of the coated vehicle from damage by stones or gravel.
The topcoat (color) is then applied by a combination of manual and automatic spraying.
The topcoat requires multiple applications to ensure adequate appearance and durability. An
oven bake may follow each topcoat application, or the individual coats may be applied wet-on-
wet with a final oven back.
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Solvent emissions occur in the application and curing stages of the surface coating
operations. The application and curing of the prime coat, guide coat, and topcoat accounted for
a majority of the VOC emitted from most assembly plants in the past. Conversions to lower
VOC content coatings and more efficient application equipment has reduced the contribution of
these operations to total plant-wide VOC emissions at many assembly plants. Final topcoat
repair, cleanup, adhesives, sound deadeners, and miscellaneous coating sources account for the
remaining emissions. Approximately 70 to 90 percent of the VOC emitted during the application
and curing process is emitted from the spray booth and flash-off areas, and 10 to 30 percent
from the bake oven.
5.4.14 Paper. Film, and Foil Coatings
12
Paper is coated for a variety of decorative and functional purpose!! with a variety of
coatings which may be waterbome, organic solvent-borne, or solventless extrusion type
materials.
The coating of pressure sensitive tapes and labels (PSTL) is an operation in which a
backing material such as paper, cloth, or cellophane is coated one or more times to create a tape
or label that sticks on contact. Adhesives and release agents are the two primary types of
coatings applied in this industry. Essentially all of the VOC emissions from the PSTL industry
come from solvent-based coatings which are used to produce 80 to 85 percent of all PSTL
products.
In the solvent-based coating process, a roll of backing material is unrolled, coated, dried,
and rolled up. The coating may be applied to the web by knife coater, blade coaler, metering
rod coater, gravure coater, reverse roll coater, or a dip and squeeze coater. After the coating
has been applied, the web moves into a drying oven where the web coating is dried by solvent
evaporation and/or cured to a final finish. Direct-fired ovens are the most common type used.
Drying ovens are typically multizoned with a separate hot air supply and exhaust for each zone.
The temperature increases from zone to zone in the direction in which the web is moving, thus
the zone maintained at the highest temperature is the final zone that the web traverses before
exiting the oven. A large drying/curing oven may have up to six zones ranging in temperature
from 43°C to 204°C.
The main emission points from paper-coating lines are the coating applicator and the oven.
In a typical paper-coating plant, about 70 percent of all emissions are from the coating lines.
The other 30 percent are emitted from solvent transfer, storage, and mixing operations. Most
of the VOC emitted by the line are from the first zone of the oven. Fugitive emissions from
solvent transfer, storage, and mixing operations can be reduced through good housekeeping
practices, such as maintaining lids on mixing vessels, and good maintenance, such as repairing
leaks promptly.
By definition, all PSTL products have an adhesive coating. It is generally the thickest
coating applied and the source of 85 to 95 percent of the total emissions from a line. In an
uncontrolled facility, essentially all of the solvent used in the coating formulation is emitted to
the atmosphere. Of these uncontrolled emissions, 80 to 95 percent are emitted from the drying
oven. A small fraction of the coating solvent may remain in the web after drying. The
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remaining 5 to 20 percent of applied solvent is lost as fugitive emissions by evaporation from
a number of small sources such as the applicator system and the coated web upstream of the
drying oven. Some fugitive losses also occur from storage and handling of solvent, spills, and
: mixing tanks, and during cleaning of equipment, such as a gravure roll.
5.4.15 Magnetic Tape Coatings ^
Organic solvent, metal-oxide particles, and suitable resins are combined to form the
coatings used by magnetic tape coating operations. The coating equipment consists of an unwind
roll for the plastic film substrate, a coating applicator, a drying oven, and a windup roll for the
coated tape. The coating mixture is supplied to the plastic film substrate by the coating
applicator (often via some sort of roll or rotogravure coater). The plastic film is carried through
the drying oven where organic solvent evaporates. The plastic substrate with the dried magnetic
coating is then rewound at the end of the line. Slitting operations to produce the consumer
product are almost always performed later as an off-line operation.
Roughly 10 percent of the solvent used by a plant evaporates from mix and storage tanks.
Another 10 percent evaporates from the coating applicator and the flash-off area between the
coater and the oven. The remainder evaporates in the drying oven and is exhausted through the
oven exhaust stack.
5.4.16 Business Machine Plastic Parts Coatings
12
Plastic parts for business machines are coated for several reasons. Exterior coatings are
applied to improve appearance, color match, and provide chemical resistance. Emissions from
plastic parts coating occur in the spray booth flash-off area and back oven. Up to 90 percent
of all VOC emissions come off in the spray booth.
5.4.17 Automotive Plastic Parts Coating
These coatings are used to finish interior and exterior plastic parts used in automotive and
other transportation equipment. Examples include bumpers, bumper covers, body panels,
dashboards, and other interior and exterior parts. Emission sources are similar to other coating
operations.
5.4.18 Flexible Packaging Printing ^
The image areas on the image cylinder of a flexographic press are raised above the
nonimage areas. A distinguishing feature is that the image carrier is made of rubber which is
attached to the cylinder. A feed cylinder which rotates in an ink fountain delivers ink to a
distribution roll, which in turn transfers ink to the image cylinder, following transfer from the
image cylinder to substrate, the ink dries by evaporation in a high velocity, low temperature
(< 120°F) air dryer. Some solvent is absorbed into the web. Typical ink solvents are alcohols,
glycols, esters, hydrocarbons, and ethers. An estimates 21,400 flexographic presses were in
operation in the United States in 1984.
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The major emission points from a flexographic press are the ink fountains, feed cylinder,
distribution roll, image cylinder, printed web, and dryer exhaust. The potential amount of VOC
emissions is equal to the total amount of solvent consumed by the printing plant if none of the
ink reacts to form an organic by-product. This includes the solvent in the raw inks, solvent in
any extenders used, the solvent added at the press, and clean-up solvent.
5.4.19 Rotogravure Publication Printing
12
In the rotogravure printing process, image areas are recessed relative to nonimage areas.
The rotating cylinder picks up ink from an ink trough or fountain. Excess ink is scraped from
the blank area by a steel doctor blade. The ink is then transferred directly as the roll contacts
the web. The web is then dried in a low temperature dryer. Typical ink solvents include
alcohols, aliphatic naphthas, aromatic hydrocarbons, esters, glycol ethers, ketones, and
nitroparaffins. It is estimated that there were approximately 1,600 rotogravure presses in the
United States in 1984.
The major emission points from a rotogravure press are the ink fountains, wet printing
cylinders, wet printer web, and drier exhaust. The total amount of organic solvent consumed
by the printing plant is the maximum potential VOC emission (if no reaction by-products are
formed during the drying operation). This consists of solvent in the raw ink, solvent contained
in any extenders used, solvent added at the press, and solvent used for cleanup.
5.4.20 Lithographic Printing 12
Lithography is a printing process characterized by a planographic image carrier (i.e., the
image and nonimage areas are on the same plane) which is mounted on a plate cylinder. The
image area is made water repellant while the nonimage area is water receptive. Rotation of the
place cylinder causes the image plate to first contact an aqueous fountain solution which typically
contains up to 25 weight percent isopropyl alcohol. This solution wets only the nonimage area
of the plate. The image plate then contacts the ink which adhered only to the image area. In
offset lithographic printing, the ink is transferred from the image plate to a rubber-covered
blanket cylinder. The blanket cylinder then transfers the image to the web. Lithographic heatset
inks, containing approximately 40 volume percent solvent, require a heated dryer to solidify the
printed ink. Other lithographic inks, containing about 5 volume percent solvent, dry by
oxidation or by absorption into the substrate.
Emission points on a web-offset lithographic printing line include the ink fountains and
associated inking rollers, the water fountains and associated dampening rollers, the plate and
blanket cylinders, the dryer, and the final printed product. Alcohol is emitted from the
dampening system and the plate and blanket cylinders at a rate of about 0.5 kilograms per
kilogram of ink consumed. Wash-up solvents are a small source of emissions from the inking
system and the plate and blanket cylinders. When heat-set inks are printed, the drying oven is
the major source of VOC emissions with 40 to 60 percent of the ink solvent evaporating from
the oven.
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5.4.21 Letterpress Printing 12
Letterpress is the oldest form of moveable type printing, with the image areas raised
relative to the blank or nonimage areas. The image carrier may be made of metal or plastic.
Viscous ink is applied to the image carrier and transferred directly to paper or other substrate.
Letterpress is the dominant printing process for periodical and newspaper publishing.
Newspaper ink is composed of petroleum oils and carbon black, but no volatile solvent The
ink "dries" by adsorption into the substrate. Web presses printing on nonporous substrates
employ solvent-borne inks which dry by evaporation. Sheet-fed presses employ solventless inks
which dry by air oxidation. There are over 10,000 commercial letterpress printing plants in the
United States.
The major VOC emission points on web letterpress printing lines are the image carrier and
inking mechanism of the press, the dryer, the chill rolls, and the printed product. About 60
percent of the solvent in the ink is lost in the drying process. Use of washup solvents contribute
to overall VOC emissions.
5.4.22 Tire Manufacturing Cements *
The tire manufacturing process generally consists of four main steps: (1) compounding
of raw materials, (2) transforming the raw materials into tire components and preparing the
components for assembly, (3) assembling the components (tire building), and (4) molding,
curing, and finishing of the assembled components into the final product. Each of these steps
is a potential source of VOC emissions.
Tire components are made in several parallel operations. Rubber stock and other raw
materials, including wire and fabric, are used to make tire tread, sidewalls, cords, belts, and
beads. The major source of VOC emissions during this step is the evaporation of VOC from
solvent-based cements. Tire building is the assembly of the various tire components to form an
uncured or "green" tire. The assembly takes place on a collapsible, rotating drum. Organic
solvents may be applied to some tire components in this step to further "tackify" (make sticky)
the rubber. Green tires are then sprayed on the inside with lubricants and on the outside with
mold release agents before molding and curing in automatic presses.
Each of the four production steps may include one or more sources of VOC emissions.
Organic solvent-based green tire spraying, undertread cementing, sidewall cementing, tire
building, tread end cementing, and bead cementing contribute 97 percent of the total VOC
emitted from tire production.
5.4.23 Miscellaneous Industrial Adhesives
Adhesives are used for joining surfaces in assembly and construction of a large variety of
products. Adhesives allow faster assembly speeds, less labor input, and more ability for joining
dissimilar materials than other fastening methods. By far the largest use of adhesives is for the
manufacture of pressure sensitive tapes and labels. Other large industrial users are automobile
manufacturing (including especially attachment of vinyl roofs), packaging laminating, and
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construction of shoes. Adhesives may be waterborne, organic solvent-borne,, or hot-melt. Only
organic solvent-borne adhesives have the potential for significant VOC emissions.
The VOC emissions from solvent-baaed adhesives are a result of the evaporation of the
solvents in the adhesive. Emissions arise mainly at the point of application and in many cases
are swept from the area with local ventilation systems. Essentially all of the organic solvent in
an adhesive is emitted to the atmosphere as the adhesive dries. Adhesives vary widely in
composition but a typical solvent-borne adhesive might contain 80 weight percent solvent so that
approximately 0.8 kg of VOC evaporates for every kg of adhesive used.
5.4.24 Metal Cleaning (Degreasing) Solvents ^
Solvent metal cleaning (degreasing) uses organic solvents to remove soluble impurities
from metal surfaces. Organic solvents include petroleum distillates, chlorinated hydrocarbons,
ketones, and alcohols. Industrial uses include solvent metals cleaning include automobiles,
electronics, appliances, furniture, jewelry, plumbing, aircraft, refrigeration, business machinery,
and fasteners.
Methods of solvent metal cleaning include cold cleaning, open top vapor degreasing, and
conveyorized degreasing. Cold cleaning uses all types of solvents with the solvent maintained
below its boiling point. Open top vapor degreasers use halogenated solvents heated to their
boiling points. Both cold cleaners and open top vapor degreasers are batch operations.
Conveyorized degreasers are loaded continuously and may operate as vapor degreasers or as cold
cleaners.
For cold cleaners, emission sources are as follows: (1) bath evaporation, (2) solvent
carry-out, (3) agitation, (4) waste solvent evaporation, and (5) spray evaporation. Unlike cold
cleaners, open top vapor degreasers lose a relatively small proportion of their solvent in the
waste material and as liquid carry-out. Most of the emissions are vapors that diffuse out of the
degreaser into the work place. These fugitive emissions escape to the atmosphere through doors,
windows, and exhausts. Emission sources for conveyorized degreasers include bath evaporation,
carry-out emissions, exhaust emissions, and waste solvent emissions. Carry-out emissions are
the largest single source.
5.4.25 Industrial Cleaning Solvents
A variety of cleaning solvents are used by industry to remove contaminants such as
adhesives, inks, paint, dirt, soil, oil, and grease. Parts, products, tools, machinery, equipment,
vessels, floors, walls, and other work areas are cleaned for a variety of reasons including
housekeeping, safety, operability, and to avoid product contamination. Solvents are used in
enormous volumes and a portion evaporates during use, making cleaning fluids a major source
of emissions of VOC.
The EPA conducted a study which focused on the cleaning practices employed in six
industries (automotive, electrical equipment, metal furniture, photographic supplies, packaging,
and magnetic tape). On average, 25 percent or more of the solvent that was used for cleaning
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purposes by the six industries was lost by spillage or evaporation. This value varied
significantly among industries depending on the type of cleaning performed.
All use of solvent for cleaning can be evaluated on the basis of one of only nine general
types: cleaning of spray guns, spray booths, equipment, large manufactured components, small
manufactured components, floors, tanks, lines, and parts. Within each group, however, there
is considerable variation, including differences in cleaning techniques, soils removed, solvency,
and a likely host of others.
5.4.26 Petroleum Drvcleanine Solvents
12
Dry cleaning is a service industry, involved in the cleaning of apparel or renting apparel.
Basically, the industry is segregated into three areas based on customers and types of services
offered. These areas are: (1) coin-operated, (2) commercial, and (3) industrial. The industry
is also subdivided according to the type of solvent used which are: petroleum solvents,
perchloroethylene (perc), and trichlorotrifiuorethane (Freon-113*). Freon-113 and perc will not
be discussed further since they are considered negligibly reactive. Dry cleaning operations are
similar to detergent and water wash operations. There are approximately 6,000 facilities in the
United States with petroleum dry cleaning equipment.
Emissions of VOC escape from dryers, washers, solvent filtration systems, settling tanks,
stills, and piping and ductwork associated with the installation and operation of these devices.
Because of the large number of variations in the types of equipment and operating practices, in
dry cleaning plants there is a large variation in emission rates. For that reason, details on
emission factors or typical plant emission rates will not be discussed here. The emission sources
in dry cleaning plants can be characterized in two broad groups - vented and fugitive emissions.
Solvent is vented from article dryers, solvent stills, and filter and article drying cabinets. The
largest source of vented emissions is from article dryers. Fugitive emissions occur from all
equipment in dry cleaning facilities, however, these emissions vary greatly since they are
dependent on equipment operating and good housekeeping practices. The major fugitive
emission sources are solvent or k'quid leaks from pipes or ductwork, and wet or not completely
dried articles, used-wet filters, and solvent and still waste which are all left in open containers
in or outside dry cleaning facilities.
5.4.27 Agricultural Insecticides and Herbicides
8
Insecticides are used in agriculture to destroy or control populations of harmful insects.
Herbicides are chemical weed killers that are used extensively on farms and other areas.
Herbicides are grouped using a multiple-classification system based on selectivity, mode of
action (contact versus translocation), timing of application, and areas covered. Herbicides are
classed as selective when they are used to kill weeds without harming the crop and as
nonselective when the purpose is to kill all vegetation. Contact herbicides kill the plant parts
to which the chemical is applied, whereas translocated (systematic) herbicides are absorbed by
roots or above-ground parts of plants and then circulate within the plant system to distant tissues.
Pesticides may be applied as liquids, dry solids, or gases. Liquid pesticides are applied
as a spray of water or oil droplets containing a solution or suspension of active ingredients.
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Pesticides formulated as dusts or granules are normally applied dry. Pesticides that exist in a
gaseous state at ambient temperature and pressure may be applied either as gases or pressurized
liquids or as solids that vaporize upon release. This type of pesticide application is known as
fumigation.
Emissions of VOC from pesticide applications are the result of volatilization of the active
ingredient (AI), organic solvents, emulsifiers, and other organic compounds that may be used
in the formulation.
5.4.28 Cutback Asphalt Paving Materials
12
Liquefied asphalts are generally prepared by cutting back or blending asphalt cement with
petroleum distillate or by emulsifying asphalt cement with water and an emulsifying agent.
Heated asphalt cement is generally used to make asphalt pavements such as asphalt concrete.
Cutback and emulsified asphalt are used in nearly all paving applications. In most applications,
cutback and emulsified asphalt are sprayed directly on the road surface; the principal other mode
is in cold mix applications normally used for wintertime patching.
Emissions from cutback asphalt occur as the petroleum distillate (diluent) evaporates; the
average diluent content in the cutback is 35 percent by volume. The percentage of diluent to
evaporate is dependent on the cure type. The emission factors are: slow cure (SC) - 20 to 30
percent of diluent content, average 25 percent; medium cure (MC) - 60 to 80 percent, average
70 percent; rapid cure (RC) - 70 to 90 percent, average 80 percent. These factors are
independent of the percent of diluent in the mix within the normal range of diluent usage for
cutback asphalts.
5.4.29 Synthetic Fiber Spinning Solvent ^
Synthetic fibers are manufactured as continuous filaments (which may then be chopped into
staple) of modified cellulose or manmade polymers. They are used to manufacture carpets,
apparel, industrial textiles, rope, tires, cigarette filters, and composite materials. There are three
broad manufacturing classifications: melt spinning, solvent spinning, and reaction spinning.
Typical polymers suitable for solvent spinning are acrylics, modacrylics, acetates,
triacetates, rayon, and spandex. Solvent spinning can be subdivided into two types of processes,
wet or dry. Both first require the polymer to be dissolved in a suitable solvent at a ratio of
about three parts solvent to one part polymer. In wet spinning, the polymer solution is extruded
through a spinneret that is submerged in a liquid that extracts the solvent, thereby precipitating
the polymer filament. In dry spinning the polymer solution is extruded into a zone of heated
gas that evaporates the solvent leaving the polymer filament behind.
5.4.30 Fabric Coating
12
Fabric coating involves the application of decorative or protective coatings to a textile
substrate. A large segment of this industry is application of rubber coatings to fabrics. More
specifically, for purposes of the regulatory program, fabric coating is the uniform application
of (1) an elastomeric or thermoplastic polymer solution, or (2) a vinyl plastisol or organisol,
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across all of erne (or both) side of a supporting fabric surface or substrate. The coating imparts
to the fabric substrate such properties as elasticity, strength, stability, appearance, and resistance
to abrasion, water, chemicals, heat, fire, or oil. Coatings are usually applied by blade, roll
coater, reverse roll coater, rotogravure coater, or dip coater.
The basic fabric coating process includes preparation of the coating, the application of the
coating to the substrate, and the drying/curing the applied coating. The web substrate is
unwound from a continuous roll, passed through a coating applicator and drying/curing oven,
and then rewound.
The major sources of VOC emissions in a fabric coating plant are the mixer and coating
storage vessels, the coating applicator, and the drying oven. The relative contribution of these
three areas are estimated at 10 to 25 percent, 20 to 30 percent, and 45 to 70 percent,
respectively. The potential VOC emissions from a fabric coating plant are equal to the total
solvent used at the plant.
5.4.31 Fabric Printing 12
Fabric printing is application of a decorative design to a fabric by intaglio (etched) roller
(another name for rotogravure), rotary screen, or flat screen printing operation. The fabric web
passes through the print machine where a print paste is applied to the substrate. After leaving
the print machine, the web passes over steam cans or through a drying oven to remove water
and organic solvent from the printed product.
The most significant source of VOC emissions in a fabric printing plant is the drying
process, either the steam cans or the ovens. Other emissions occur as fugitive VOC. These are
as evaporation from wastewater streams, open print paste barrels, printing troughs, the printing
rollers and screens, "strikethrough" onto the backing material, and from the printed fabric before
it reaches the drying process.
5.5 PRODUCTS ADDRESSED BY SPECIAL STUDIES
Several categories of products fall beyond the scope of Sections 5.3 and 5.4. These
categories were the subjects of special studies carried out by the EPA to develop 1990 emission
estimates based primarily on information in the literature. For those products for which data
on emissions was not available, any useful information (e.g., VOC content, function of the
product, etc.) was summarized and included in the inventory report. Specific methodology is
discussed for each category included. The estimates presented in Table 5-3 have been scaled
down based on population in ozone nonattainment areas using the adjustment factor discussed
in Section 5.2.
5.5.1 Construction Materials
5.5.1.1 Building Materials and Indoor Air Sources ^
Since the mid-1970's, a growing number of complaints have surfaced regarding the indoor
environment to which occupants of modem buildings are exposed. Energy efficiency also
became increasingly important during this time. Consequently, new buildings were being built
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TABLE 5-3
VOC EMISSIONS IN NONATTAINMENT AREAS FOR
PRODUCTS COVERED BY SPECIAL STUDIES
Category
CONSTRUCTION MATERIALS
Particle board
Plywood
Wallpaper
Carpeting
Roofing - built-up
Roofing - elastomeric
Roofing - modified bitumen
Asphalt concrete paving materials
SMALL COMBUSTION SOURCES
Kerosene space heaters
Camp stoves, lanterns, heaters
Commercial explosives
Artificial fire logs
TEXTILE INDUSTRY
Platen Adhesives
Equipment cleaning solvents
Spot Cleaners - Screen Printers
Spot Cleaners - Woven Goods
Spot Cleaners - Knit Goods
Nonattain Area
Emissions
(tons/year) a
*
*
*
*
7,126
9,123
2,276
360
39
6
2,422
154
2,092
68
848
0*
0*
Year
1989
1989
1989
1991
1990
1990
1990
1990
1990
1990
1990
1990
1990
Ref
15
15
15
15
16
16
16
17
15
15
15
15
18
18
18
18
18
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TABLE 5-3 (Continued)
VOC EMISSIONS IN NON ATTAINMENT AREAS FOR
PRODUCTS COVERED BY SPECIAL STUDIES
Category
MISCELLANEOUS PRODUCTS
Mold Release Agents
Automotive Repair - Parts Washers
Fiberglass Boat Manufacturing Products
TOTAL FOR ALL SPECIAL STUDIES
Nonattain Area
Emissions
(tons/year) a
75,400
2,607
12,100
114,621
Year
1989
1987
1990
Ref
16
17
19
This category was investigated and is discussed in the inventory report, but an emission
estimate could not be developed based on the available information.
Nonattainment area emission estimates were obtained by adjusting nationwide estimates
according to the distribution of nationwide population in nonattainment areas in 1990.
Estimates for categories without this footnote were determined specifically for
nonattainment areas and needed no further adjustment.
148 million (nonattainment areas)
248 million (nationwide)
= 59.68%
60%
These activities resulted in no VOC emissions. However, cleaning is performed using
exempt (non-VOC) organic solvents (e.g., 1,1,1 trichloroethane, etc.)
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with less outside air infiltration, thus confining more indoor air pollutants. Since the early
1980's, much work has been done by the EPA and other groups to identify and measure VOC
emission rates from building materials and consumer products in small test chambers and
laboratories.
The building materials source category contains a number of different product lines, each
with a variety of manufacturers and manufacturing methods. For the purposes of this report,
the term building materials refers to carpet, plywood, particle board, chipboard, fiberboard,
treated lumber, gypsum board, laminated plastics, insulation, linoleum, and wallpaper. Each
of these materials has been found to have the potential of emitting various types of VOC during
their expected lifetime. These materials are present in many kinds of structures including
apartments, automobiles, commercial buildings, hospitals, mobile homes, nursing homes, office
buildings, residences, and schools. Previous studies of building materials have shown emissions
to be very dependent upon test variables such as air exchange rate, temperature, humidity,
product loading (area of product/volume of test chamber), and age of material. To date, much
research has been conducted to determine the concentrations of speciated VOC in the ambient
air surrounding building materials. This research has been performed in chamber tests,
laboratory experiments, and on-site tests of various types of buildings. However, only a limited
number of these studies have developed emission rates for these materials. Several short term
tests (i.e., days and weeks) have specified emission rates calculated as an average for the
duration of the experiment. However, based on the current available literature, no long term
tests (i.e., one year) have been conducted to determine an annual average speciated VOC
emission rate from any one specific type of building material. Therefore, no annualized total
or speciated VOC emission estimates from building materials can be developed at this time.
5.5.1.2 Roofing Materials 16
A modern roof design normally includes a structure to carry loads, insulation to control
heat flow, a barrier to control air and vapor flow, and vapor retarders to prevent water retention.
Several different types of roofs have been developed to accomplish these objectives. The main
types of roofs used today are sloped roofing materials (e.g., asphalt shingles, wood shakes and
shingles, slate roofs, thatched roofs, etc.), built-up roofing (BUR), elastomeric (primarily
ethylene-propylene-diene monomer, or EPDM), thermoplastic, modified bitumen (MBR), and
liquid-applied roofing.
The total amount of commercial/industrial roofing performed in 1989 was approximately
3.3 billion square feet, with 1.3 billion square feet as BUR, 1 billion square feet as EPDM, and
0.7 billion square feet as MBR. These three roofing types make up over 90 percent of the
commercial roofing market.
In 1970, BUR was 90 percent of the roofing market; in 1989 it was less than 40 percent.
In the BUR application process, several layers of felts, insulations, and other materials are
applied using hot asphalt, asphalt emulsions, or asphalt mastics. Coal tar may be used in place
of asphalt.
A typical BUR reroofing job begins with surface preparation of the roof by removing the old
roof and surfacing material (e.g., gravel). After the surface is prepared, an asphalt primer is
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applied if the deck is constructed of concrete. Next, a base ply or insulation layer is applied
using hot asphalt or cold process asphalt. Several layers of felts are then attached to the roof
with an intermediary layer of asphalt between each layer. A cap sheet layer is then applied,
followed by a flood coating of asphalt to seal the roof. Flashing, vents, and other areas of the
roof receive a layering of flashing cement to provide extra sealing capabilities in these areas.
Solvent cleaners are used to remove asphaltic materials from tools and may also be used by
workers to clean their hands. Emissions points for BUR are the application of roofing materials
using asphaltic compounds, flashing cements, asphalt primers, and cleaning operations.
Elastomeric roofing consists of natural and synthetic rubbers and rubberlike materials.
The most common elastomeric roofing material is ethylene-propylene-diene monomer (EPDM).
Three methods have been identified for the application of EPDM roofing systems: loose-laid
and ballasted, comprising 70 percent of the total; fully-adhered, comprising 20 percent of the
total; and mechanically-fastened, comprising 10 percent of the industry. A typical fully-adhered
EPDM roofing process involves removing the old roofing system, surfacing materials, and
debris, leaving a clean substrate. EPDM sheets are laid side-by-side with a three inch overlap
and are bonded to the roof using bonding cement. The seams are cleaned and primed in
preparation for taping. Tape is applied to each seam leaving a waterproof surface. General
cleaning operations are carried out daily to remove roofing materials from skin, tools, clothing,
etc. Emissions result from the use of primers, cements, and cleaners.
The MBR process is very similar to the BUR category. Modified bitumen sheets are
constructed using asphaltic materials like BUR felts and plies, but are augmented by adding
thermoplastic materials like styrene-butadiene-styrene (SBS) or atactic polypropylene (APP).
These plasticizers lend greater elongation and roof movement tolerance. The modified bitumen
sheets are typically built-up in the factory. Fewer layers of modified bitumen sheets are applied
in a typical roofing job than in a BUR job since the MBR sheets are already built up.
Modified bitumen can be applied in several ways, including hot asphalt, propane torch-
activated adhesive and self-adhering sheets; squeegee-applied cold adhesives; and spray-applied
cold adhesives. The most common means of attaching MBR are hot asphalt, torch activation,
and self-adhering sheets, representing 99 percent of the market.
5.5.1.3 Asphalt Concrete Paving Materials 17
Generally, paved roads are constructed of either bituminous asphalt concrete or portland
cement concrete. Asphalt concrete is blended at a facility that may be located several hours
from the job site. The hot asphalt concrete mixture (hot mix) is blended and maintained at
approximately 300°F until being laid and compacted. The major constituent of asphalt concrete
is aggregate, a mixture of sand and gravel. Asphalt, a derivative of the bottom cut in the
distillation of crude oil, serves as the binder for the aggregate.
An estimated 460 to 500 million tons of hot mix was prepared in 1991. This estimate
does not include cutback asphalt. Approximately 5 percent of the hot mix is asphalt. Asphalt
concrete contains low concentrations of VOC when properly prepared. A common test to
determine the suitability of asphalt concrete is the "loss on heating" test. When heated, if more
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than O.S percent volatilizes, the material is rejected. In practice, asphalt concrete typically
contains about 0.0025 percent VOC.
Based on 500 million tons of asphalt concrete used annually, the usage of asphalt cement
in this material (5%) is estimated to be 25 million tons nationwide. At a typical VOC content
of 0.0025 percent, the asphalt cement contains approximately 600 tons of VOC. It is assumed
that all the VOC contained in the concrete are emitted.
In the asphalt paving industry, regular equipment cleaning currently is performed using
high pressure water sprays rather than solvents, although this has not always been the practice.
However, many construction crews coat the truck and hopper beds with diesel fuel to prevent
sticking. The asphalt concrete absorbs any excess liquid, which ultimately evaporates. Diesel
fuel is also used to clean shovels and rakes. There is insufficient data to develop an estimate
of these additional emissions.
5.5.2 Small Combustion Sources
5.5.2.1 Kerosene Space Heaters "
Kerosene heaters are typically used as a supplemental heat source in areas in which: 1)
residential central heating systems are not installed, 2) inadequate heat is available and/or 3)
temperatures are extremely cold. Kerosene heaters usually supplement other heating sources
such as electric, fuel oil and gas furnaces. Portable kerosene heaters are limited to supplemental
heating because the kerosene tank on each heater is too small to provide continuous heating
without constant refilling.
Kerosene heaters can be divided into three main categories: (1) convective (white flame),
(2) radiant (blue flame) and (3) hybrid (two-stage). The most popular type of portable kerosene
heater among consumers is the convective heater. These three types of heaters are described
below.
1) The convective (white flame) heater operates at relatively high combustion
temperatures. It uses a relatively simple unobstructed wick.
2) The radiant (blue flame) heater operates at lower temperatures than does the
convective heater. It uses a cylindrical wick. Flames extend up from the wick into
a perforated metal baffle, consisting of two concentric cylinders inside a glass
plenum. After the warm up period the metal baffle glows red hot, causing a portion
of heat to be output as radiative heat.
3) The hybrid (two-stage) heater is similar to the radiant heater, except a second
chamber is located above the radiant element where more combustion air is
introduced. In this region the flame temperature is allowed to rise, the color
becomes white, and secondary combustion of unburned hydrocarbons with an
increase in carbon monoxide production occurs before the combustion product
leaves the burner. This type of heater incorporates features from both radiant and
convective heaters; thus it is appropriately named "hybrid."
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Although kerosene heaters are a logical choice for supplementing a central heating source,
their lack of exhaust ventilation has prompted a considerable amount of research on the effects
of emissions from kerosene heaters on indoor air quality. These studies have quantified
emissions rates and provide the basis for a general methodology to estimate emissions from
portable kerosene heaters.
The major VOC pollutant from portable, unvented kerosene heaters is the unburnt
combustible formaldehyde (HCHO). Significant quantities of formaldehyde are produced and
emitted to an indoor atmosphere under the conditions which portable heaters are normally
operated.
5.5.2.2 Camp Stoves and Lanterns ^
Camp stoves, camp lanterns and portable heaters are used in the U.S. for various outdoor
activities including backpacking and camping, or work in open areas. Two primary kinds of
camp stoves sold in the U.S. are backpack type single burner stoves and family type two or
three burner stoves. These stoves are designed to bum Coleman* fuel (GyH^, regular
unleaded gasoline, kerosene, or propane gas. Other fuels used less frequently include aviation
gas, starter fluid (ethyl ether), butane and isobutane. Many camping supply stores sell propane
and butanes as liquefied gases in pressurized containers.
Camping lanterns used include single or dual mantle lanterns which burn propane gas,
Coleman* fuel, unleaded gasoline or kerosene. Portable heaters, used for outdoor heating jobs,
include the standard single-head or double-head bulk mount types which are usually designed
to operate on propane gas.
Given the limited time and the difficulty in obtaining all the relevant information, it was
not possible to accurately calculate the total annual VOC emissions from this product category
during this study. Based on the information provided by Coleman* from the use of Coleman*
stoves and lanterns, a first approximate estimate of total VOC emissions per year was calculated
to be less than 10 tons of unbumt Coleman® fuel. Emissions calculation data are not provided
due to the lack of more accurate emissions concentrations which should include fugitive
emissions.
5.5.2.3 Artificial Fireplace Logs and Other Fire Starting Materials 15
Fire starting materials are products used to aid or initiate the combustion process of
various consumer products. Fire starting materials include solid and gel starters, and alternative
combustion materials such as self-starting charcoal and artificial fire logs. These products may
be used for household fireplaces and for outdoor cooking purposes as in grills and camp stoves.
These materials may be used throughout the year. However it is not likely to expect as much
camping or outdoor activities in the winter as in the summer.
Solid starters usually consist of wood shavings held together with paraffin wax. The actual
percentages by volume/weight of these components could not be found at this time although
the material was found to be similar to manufactured fire logs. The Department of Ecology,
State of Washington stated that products of combustion due to the burning of one type of solid
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starter are not found to be any more polluting than the burning of artificial fire logs. Gel
starters are usually alcohol-based products. Alco Brite* manufactures a gelled alcohol fuel
called Cook 'n' Heat Fuel* which contains 1000 ppm ethanol and 200 ppm methanol. Other
similar gel products include the Snap-On-Stove* and Alco Brite* Fire Starter. It was not
possible during this study to find out whether Alco Brite has performed any emissions testing
of its products. Another manufacturer makes a product known as Mautz Fire Ribbons which
consists of a standard petroleum-based solvent, usually p-naphtha, mixed with clay. This product
consists of 95 percent solvent and is often used to start fires in bar-b-que grills and torches. No
other product types or consumption data from solid or gel starters were located during the time
period of this study.
Artificial household fire logs are made by compressing sawdust and petroleum wax.
Canadian Firelog Ltd. makes a product that contains cedar sawdust (38 percent), paraffin wax
(61 percent), calcium carbonate (0.75 percent) and copper sulfate (0.5 percent). One source
indicated that the product composition of fire logs does not vary drastically from manufacturer
to manufacturer. A representative from Duraflame Firelogs estimated that approximately 40
to 60 percent of households in the U.S. use artificial fire logs and of these 15 percent are
regular users and up to 30 percent are occasional users. He projected that between 10 to 12
million log cases, each weighing 30 to 36 pounds are sold each year in the U.S.
In 1987, Canadian Firelog Ltd. had research conducted to test atmospheric emissions from
the burning of their product. The test was conducted by measuring stack emissions from a wood
burning stove. This testing measured emissions for various products of combustion including
polynuclear aromatic hydrocarbons (PAHs). The results of the studv indicated that the total
PAHs were at minimal concentrations of no greater than 0.02 mg/m . Using the information
from their study it is possible to estimate emissions from similar products. The assumption
made here is that the composition of artificial fire logs does not greatly vary from manufacturer
to manufacturer and therefore emissions will be similar.
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5.5.3 Products Used in the Textile Industry 18
The textile industry includes facilities involved in the following activities:
fiber preparation followed by manufacturing of yam and thread;
manufacturing of woven fabrics, knit fabrics, carpets, and rugs from yam;
dyeing and finishing of fiber, yam, fabric, knit, and woven apparel;
manufacturing of apparel and other articles from yarn; and
manufacturing of nonwoven fabrics and other miscellaneous textiles.
Both man-made and natural fibers are processed. Examples of the latter group include
cotton, wool, silk, flax, and jute while the former include such fibers as rayon, polyester,
acetate, and nylon. Blends of these fibers may also be processed.
Estimates of VOC emissions can be made for certain solvent-containing products mat are
used in the textile industry. In this study, estimates were calculated for emissions from:
• parts washer solvents used by garment screen printers;
• platen adhesives; and
• spot cleaners.
Garment screen printers primarily use parts washer solvents to clean ink from press parts.
Most garment screen printers also use platen adhesives. Spot cleaners may be used in any textile
facility that produces a finished product (e.g., thread, yam, fabric, garments, etc.).
In some instances, it is difficult or impossible to estimate emissions from a specific
product. For example, estimates of emissions from winder cleaners are complicated by the fact
that facilities may use products that contain very different amounts of solvent. Estimates of
emissions from cot adhesives pose a similar problem since some facilities use fiber-,
metal-, or plastic-lined cots that do not require adhesive. The same difficulty is encountered
when attempting to determine emissions from the screen cleaners used in garment screen printing
facilities. Some facilities use products containing 100 percent petroleum distillates while others
use water-based products containing d-limonene. Similarly, the screen reclaimers that are used
may or may not contain solvent. Although data were collected during the site visits on each of
these specific products, this information may not represent the true distribution of their use
within the industry and, therefore, cannot be extrapolated on a national basis for emission
estimates.
5.5.3.1 Parts Washer Solvent
Two factors may affect the emission of solvent from parts washers: evaporation from the
sink and evaporation from depleted solvent that is splattered or carried out of the washer on wet
parts. In general, newer models of parts washers are designed so that the solvent returns by
gravity to the reservoir, where it is less likely to evaporate. Therefore, for the purposes of this
estimate, emissions due to evaporation from the sink will be ignored. In some instances, these
emissions may be significant (e.g., at a facility where an older parts washer with an open
reservoir is used). Exact measurements of solvent depletion through carryout are not available.
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Therefore, an assumption that 10 percent of the solvent is lost during the interval of usage was
used for this calculation.
The emission estimates are also based on usage data collected from site visits to three
garment screen printing facilities. The amount of parts washer solvent used by a printer will
depend not only on the number of press pieces cleaned but also, to some extent, on the number
of garments printed. Therefore, an estimate of the amount of parts cleaning solvent used per
garment was Cjlcu1**1*1 and used to determine emissions.
5.5.3.2 Platen Adhesive*
The emissions estimates for platen adhesives were determined from two sources of data:
(1) platen adhesive usage data; and (2) the total number of garment screen printing facilities.
The outcome of the estimate shows that 4,935.9 tons of platen adhesives are used by garment
screen printers each year. Water-based platen adhesives account for 2.6 percent, or 126.6 tons,
of the usage. Yearly VOC emissions are 3,486.4 tons, of which 37.6 percent is from VOC
propellants. Non-VOC organic chemicals emissions are 797.1 tons; 1,1,1-TCA and MeC^
account for 44.0 and 56.0 percent, respectively, of this amount.
5.5.3.3 Spot Cleaners
Only emissions from garment screen printers and finishers of woven or knit goods were
determined in this section. Garment screen printers use 3,256.3 tons of VOC-based spot
cleaners each year. Finishers of woven and knit goods use spot cleaners which contain no VOC
but which contain 1,1,1 trichloroethane. Therefore, no VOC emissions can be attributed to the
use of spot cleaners in these two segments of the industry.
5.5.4 Miscellaneous Consumer and Commercial Products
5.5.4. 1 Mold Release Agents 16
A mold release agent (MRA) can be generically described as any substance used to control
or eliminate the adhesion of a material to itself or to another material. The MRA prevents the
molded product from sticking to the mold so that the product can easily be removed in one
piece. Factors such as penetration, chemical reaction and compatibility, low surface tension,
surface configuration, and differences in polarity between the two materials influence adhesion
between materials. MRA's may also be known as abherents, anti-blocking agents, external or
surface lubricants, parting agents, and slip aids. The MRA consists of the active ingredient (the
ingredient mat actually causes the abhesion) and a carrier or additive that is used to apply the
MRA. The active ingredient is most often inert, that is, it contains no VOC. The carriers and
additives often contain VOC, although non-VOC carriers and additives may be used. Major
industrial applications for MRA's include casting, molding, forming, and materials transfer
operations in a wide variety of industries, including plastic (or polymer) processing, rubber,
metal processing, glass, food processing, textiles, printing, and others.
The category is divided into two major types of agents: topical coatings and semi-
permanents. Topical coatings, which currently dominate the MRA market, are further divided
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into external MRA's and internal MRA's. External MRA's operate much in the same manner
as oil, lard, and nonstick sprays operate on cookware. Abherents can be applied to a surface
by standard coating methods such as spraying, brushing, dusting, dipping, electrostatic powder
coating, and plasma arc coating. The product (e.g., resin, metal, rubber, glass, etc.) is injected,
laid, rolled, sprayed, etc., in the mold where the product is cured. The part is then released
from the mold and the MRA is reapplied to the mold.
Internal MRA's, typically metallic stearates, are agents that are added to the resin itself.
While there is no consensus as to how such agents work, one hypothesis is that the MRA
migrates to the surface of the resin, that is, to the part/mold interface, during the interval
between the injection and the ejection. The agent then acts as an external release agent,
essentially lubricating the boundary. A number of factors influence the performance of internal
MRA's, including solubility in the resin, rate of migration, lubricity, melting point of the
additive, and extent of electrostatic inhibition.
Semipermanent*, or multiple release products, are a relatively new concept in release
agents. Semipermanents allow a large number of processing cycles to occur before re-
application of the MRA is needed. They are usually water- or solvent-based with the latter
predominantly used in heat-cured systems. They can be used to coat the mold or can be applied
to become an integral part of the mold. Advantages include low buildup, promotion of excellent
part surface and finish, minimal transfer to the part, high release efficiencies, low or non-
toxicity of some products and high temperature stability (up to 37S°C).^
Emissions from MRA use can occur at several points in the application process and depend
primarily on the mode of application. With external MRA's, VOC emissions will occur from
the application of sprays and liquids. Emissions points are the applicator, the mold and the
product. With internal MRA's, emissions may occur from the surface of the mold and the
surface of the product. However, most internal mold release agents are not mixed with additives
and carriers, and therefore, there would be no VOC emissions. Emissions points for application
and use of semipermanents are similar to those of external MRA's. However, since these
MRA's are not applied as frequently as externals, their relative emissions (assuming the same
VOC content as a comparable external MRA) will be lower.
Another source of emissions from the MRA application process involves clean up
activities. Mold surfaces are cleaned at regular intervals to increase the efficiency of the MRA.
Many of the products used in clean up are solvents with high VOC contents (e.g., mineral
spirits, trichloroethylene).
5.5.4.2 Products Used in the Manufacture of Fiberglass Boats 19
The fiberglass boat manufacturing and repair industry consists of about 1,800 facilities.
These facilities employ about 47,000 people and are located in 34 of the 48 continental United
States. About 88 percent of these establishments are small operations, employing less than 50
people. States that have a large number of boat manufacturing facilities include California,
Florida, Illinois, Indiana, Michigan, North Carolina, South Carolina, Tennessee, Texas, and
Washington.
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The most common fiberglass boat production method is open contact molding. This
method consists of laying up plies of fiberglass reinforcement impregnated with resin on an open
male (convex) or female (concave) mold. For manufacturing boats, a female mold is generally
preferred since it yields a smooth outer surface which is more desirable for hulls and decks.
The layers are built up to the desired thickness and allowed to cure.
The initial layer of resin is formed without any reinforcing material by spraying gel coat
(unsaturated polyester resin, catalyst, and pigments) into the empty mold to a precise thickness.
After allowing the gel coat to cure fully, laminates of resin and fiberglass are applied by
machine lay-up, hand lay-up, or spray lay-up. Machine lay-up involves the simultaneous
mechanical application of fiberglass reinforcement material and is generally reserved for large
hull boats; e.g., sailboats with deep keels. In hand lay-up, resin is brushed or sprayed on the
tacky surface of the gel coat, the fiberglass reinforcement material is placed into the mold, then
the laminate is completely wet out with resin and rolled by hand to remove air pockets and other
imperfections. The spray lay-up method uses a chopper gun which simultaneously deposits
chopped strand fiberglass and catalyzed resin on the mold, after which rollers are used, as in
hand lay-up, to remove entrapped air.
Two alternative closed molding methods which have been experimented with in the
fiberglass boat manufacturing industry are bag molding and resin transfer molding (RTM). Bag
molding uses a bag or flexible membrane to apply vacuum or pressure during the molding
operation. Vacuum bag molding applies pressure against the laminate by drawing a vacuum
under a cellophane, vinyl, or nylon bag which covers the laminate. Pressure bag holding forces
the bag against the laminate using compressed air or steam. In the RTM process, fiberglass
reinforcement consisting of continuous or chopped strand glass fiber mats is placed between
halves of a mold. After the mold is closed, catalyzed resin is injected into the mold and allowed
to cure. The mold is then opened and the finished part removed. The major technical difficulty
in using this process for boat manufacturing is that resin void spaces may occur, rendering the
part unusable. Also, highly skilled labor is required for RTM to be successful.
VOC emissions from fiberglass boat manufacturing consist mainly of acetone and styrene.
There are four areas in the fiberglass boat production process where VOC may be emitted to the
atmosphere: resin storage, production, assembly, and waste disposal. The major emissions
sources are exhausts from gel coat spray booths, room exhausts from the lamination area, and
evaporation of acetone or other solvents during cleanup. Emission factors for resin application
in open contact molding range from 5 to 13 Ib styrene per 100 Ib of styrene used. Emissions
from gel coat application and curing are 26 to 35 Ib per Ib of styrene monomer used. Cleaning
solvent emissions, primarily acetone, can account for 36 percent of the total VOC emissions and
are about equal to 56 percent of the styrene emissions.
5.5.4.3 Automotive Repair Parts Washers l7
A large variety of services may be offered by an automotive repair facility. In addition
to engine maintenance, these facilities may repair and service brakes, transmissions, and cooling,
air conditioning, and electrical systems. Parts cleaning is common to most facilities and often
involves the use of a parts washer.
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These washers, which may be maintained and serviced by the facility itself or by an
outside company, usually consist of a sink which covers a drum containing solvent and a pump
with a filtered intake. The pump circulates solvent from the drum to the sink through a flexible
hose. A brush, sometimes mounted to the nozzle of the hose, is used to aid cleaning. Many
newer models have a lid that closes to reduce solvent loss through evaporation. Some older
parts washers consist of a grate over an open reservoir of solvent. Self-contained systems for
immersing parts in solvent for several hours are widely used.
The solvents used in parts washers can vary, but most are based on petroleum distillates.
One commonly used solvent contains 85 percent petroleum distillates. Carburetors are usually
cleaned by immersion in cleaners that may contain other solvents. One such solvent system used
for carburetors is 2-butoxy-l-ethanol and n-methyl-pyrolidine. Other solvents may include
methlyene chloride.
Emissions can be attributed to evaporation from the sink and solvent loss through
splattering, spillage, or incomplete drainage of cleaned parts. For older washers, evaporation
occurs even when the cleaner is not in use. In newer models, the solvent is returned to the
drum, and the sink is equipped with a cover to reduce emissions when the cleaner is not in use.
Typical parts washers have a storage capacity of 20 gallons. The washers are usually serviced
every 30 days, when the dirty solvent is collected and clean solvent installed in the machine.
Estimates of VOC emissions from these cleaners were made based on the assumption that
10 percent (2 gallons) of the solvent is lost during the typical service interval of 1 month. The
annual losses are estimated to be 157 pounds per machine. In 1990, there were approximately
55,000 repair facilities nationwide. Assuming one machine per shop, nationwide emissions were
estimated to be 4317 tons per year.
5.6 REFERENCES
1. Letter from D. Fratz, Chemical Specialties Manufacturers Association, to B. Moore, U.S.
EPA, Office of Air Quality Planning and Standards, Comments on raw survey data
concerning compounds reported, percent VOC emitted, and market share reporting, March
25, 1994.
2. Letter from J. Graf, Cosmetic, Toiletry, and Fragrance Association, to B. Moore, U.S.
EPA, Office of Air Quality Planning and Standards, Comments concerning percent VOC
emitted and market share reporting, May 6, 1994.
3. Letter from R. Sedlak, Soap and Detergent Association, to B. Moore, U.S. EPA, Office
of Air Quality Planning and Standards, Comments on percent VOC emitted and market
share reporting, May 16, 1994.
4. Letter from D. Fratz, Chemical Specialties Manufacturers Association, to B. Moore, U.S.
EPA, Office of Air Quality Planning and Standards, Further comments concerning
compounds reported and percent VOC emitted, June 27, 1994.
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5. Letter from R. Sedlak, Soap and Detergent Association, to B. Moore, U.S. EPA, Office
of Air Quality Planning and Standards, Further comments on percent VOC emitted from
laundry and dishwashing products, August 8, 1994.
6. U.S. EPA, Requirements for Preparation, Adoption, and Submitted of Implementation
Plans; Approval and Promulgation of Implementation Plans, Federal Register. 57 FR
3941, February 3, 1992.
7. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Architectural and Industrial Maintenance Coatings, Draft Report, September
1994.
8. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Alternative Control Techniques - VOC Emissions from Automobile Reftnishing,
(EPA-453/R-94-031), April 1994.
9. Aerospace Paints and Coatings NESHAP - Proposed Rule under 40 CFR Part 63, 59 FR
29216, June 6, 1994.
10. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Wood Furniture Coatings NESHAP - background for proposed rule (under
development)
11. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Alternative Control Techniques - Surface Coating Operations At Shipbuilding
and Ship Repair Facilities, (EPA-453/R-94-032), April 1994.
12. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Alternative Control Techniques - Control Techniques for Volatile Organic
Compound Emissions from Stationary Sources, (EPA-453/R-92-018), December 1992.
13. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Alternative Control Techniques - Industrial Cleaning Solvents, (EPA-453/R-94-
015), February 1994.
14. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Alternative Control Techniques - Control of VOC Emissions from Agricultural
Pesticide Application, (EPA-453/R-92-011), March 1993.
15. U.S. EPA Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina, Technical Memoranda on Non-Survey Categories of Consumer and Commercial
Products, TRC Environmental Corporation, Chapel Hill, North Carolina, 1993.
16. U.S. EPA Air and Energy Engineering Research Laboratory, Research Triangle Park,
North Carolina, Source Characterizations and Emission Estimates for Mold Release Agents
and Roofing Applications, Southern Research Institute, September 1993.
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17. U.S. EPA Air and Energy Engineering Research Laboratory, Research Triangle Park,
North Carolina, Evaluation of Volatile Organic Emissions Data for Nonprocess Solvent
Use in 25 Commercial and Industrial Business Categories, (EPA-600/R-94-019), Research
Triangle Institute, February 1994.
18. U.S. EPA Air and Energy Engineering Research Laboratory, Research Triangle Park,
North Carolina, Nonprocess Solvent Use in the Textile Industry, Research Triangle
Institute, August 1993.
19. U.S. EPA Air and Energy Engineering Research Laboratory, Research Triangle Park,
North Carolina, Project Summary - Assessment of VOC Emissions from Fiberglass Boat
Manufacturing, (EPA-600/S2-90/019), Radian Corporation, June 1990.
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CHAPTER 6
FATE OF CONSUMER PRODUCT VOC
IN LANDFILLS AND WASTEWATER
The two studies summarized in this chapter were undertaken in order to determine whether
adjustments to VOC inventory data should be made to account for the VOC in consumer
products which enter landfills or wastewater and, due to physical or chemical mechanisms, do
not enter the ambient air. It is important to keep in mind that the purpose of the studies is to
establish the ultimate fate of consumer product VOC other than emissions to the ambient air.
The purpose was not to determine the impact of consumer products on landfills and/or
wastewater treatment systems.
6.1 FATE OF CONSUMER PRODUCT VOC IN LANDFILLS
This study was initiated by EPA with the specific objective of investigating the fate of
VOC in consumer products disposed of in municipal landfills. This effort was undertaken in
order to determine whether the VOC remaining in spent consumer product containers is
ultimately emitted to the air, and whether the EPA's emission estimates should be adjusted to
account for fates other than emission to the air. Key factors in this determination are landfill
operating practices, characteristics of the packaging, and chemical/physical properties of the
VOC.
6.1.1 Landfill Design
The two major approaches to landfilling are the trench method and the area method.
Results of the 1987 EPA survey of MSW landfills indicate that about 70 percent of the landfills
in the United States use the trench method and 28 percent use the area method, while 6 percent
use another method (some landfills use a combination of methods).
The trench method is based on excavating trenches that are designed to hold the amount
of waste expected to be received during a single day. Trenches are typically 100 to 400 feet
long, 3 to 6 feet deep, and IS to 25 feet wide. The waste is spread in layers 1.5 to 2 feet thick
and then compacted before the next layer is applied. The trench method is most suitable on flat
or gently rolling land with a low groundwater table.
The area method involves spreading waste over the natural ground surface or landfill liner.
Waste is deposited in layers of less than 2 feet in depth, which are then compacted before
successive layers are applied. The area method is often used in areas such as California, where
natural depressions (e.g., canyons) are abundant. If the landfill site has a high water table, the
trench method may not be feasible and the area method must be used. The number of layers
is restricted by safety considerations and limitations placed on the landfill by the community or
by permit.
The basic landfill cell is common to various landfilling methods. A cell is an area of the
landfill that is designated to be filled within a day and closed at the end of the day. Waste is
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spread in the designated area and compacted, and more waste is applied and compacted until
waste operations are concluded for that cell. A daily cover is then applied and compacted,
resulting in a completed cell, of usually less than 8 feet in height. Series of cells at the same
height constitute a lift. Intermediate cover is generally placed between lifts. The working face
of a cell can extend to the facility boundaries and may be designed to accommodate a specific
number of vehicles unloading at the same time. It is kept as small as possible in order to reduce
the problem of litter control. Waste is compacted into the cell at compaction densities ranging
from 500 to 1,500 lb/yd3. Most landfills achieve waste densities on the higher side of this
range.
6.1.2 Factors Affecting VOC Release *Q thq Atmosphere
The fate-determining mechanisms for the VOC in landfills can be divided into two groups:
(1) VOC-release mechanisms primarily associated with landfill operating practices, and
(2) potential chemical and physical mechanisms that take place within the landfill system.
Superimposed on these two groups are the physical and chemical characteristics [i.e., physical
state (solid, liquid, vapor), vapor pressure, boiling point, molecular weight, solubility,
adsorption properties, and reaction potential] of the individual VOC.
Volatile organic compounds in consumer product residuals placed in landfills may be in
one of three physical states: gas, liquid, or solid. The following factors determine how and
when the residual VOC will be released following placement in the landfill:
• Landfill operating practices,
• Characteristics of product packaging,
• Physical and chemical properties of the VOC, and
• Existence of emission controls at the landfill.
These factors are interrelated in terms of how they affect the fate of the VOC. Whether
a consumer product is in the process of being placed in a landfill or has already been buried will
determine which factor predominates.
Figure 6-1 presents a flowchart identifying potential pathways for VOC in consumer
product residuals once they are placed in a landfill. A detailed discussion of factors that affect
each step in a given pathway are presented below, followed by a discussion focused on the
potential physical and chemical pathways for the VOC of interest in this study.
6.1.2.1 Landfill Operating Practices
Waste handling prior to disposal and the use of landfill equipment to crush and compact
waste will cause most product containers to be ruptured or broken almost immediately upon
entering the landfill. Once garbage is compressed in trucks (which exert a pressure of up to
50 Ib/in^) and crushed and compacted by landfill machinery, it is highly likely that most plastic
and glass containers will be crushed or ruptured. Although metal containers are more durable
than plastic or glass, they will probably be affected in a similar manner. These theories are
supported by a study of residential refuse delivered to a landfill that found 95 percent of
household product containers empty.
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Newly received waste at a landfill is likely to remain in contact with the ambient air for
several hours while the waste is covered and possibly compacted. Landfill operators crush and
compact the received waste and use an earth cover at the end of the day. Therefore, consumer
product residuals will probably be exposed to the air for a period of time after initial placement.
The physical and chemical characteristics of a VOC will determine whether it enters the air
immediately or is actually buried in the landfill and follows a different pathway (e.g.,
absorption, chemical reaction, biodegradation). The various pathways that VOC may take in
a landfill are discussed in more detail later in this section.
6.1.2.2 Product Packaging
Some landfills do not extensively process (i.e., compact, spread, or excavate) waste once
it is placed in the landfill. This allows product containers to remain intact and VOC are released
over a period of time. One of the factors affecting the rate of VOC release when product
residuals remain in the container is the type of product packaging. For example, in aerosol
products, VOC may leak from the container through failed gaskets or o-rings. With nonaerosol
products, VOC may escape through seals in the caps and covers of product containers. Over
time, the product packaging and seal materials will degrade and VOC will be released more
readily.
With containers made from plastic (e.g., polyethylene, polypropylene, polyethylene
terephthalate), release of VOC may occur through permeation, as all plastics can be permeated.
This phenomenon is generally a function of the type of material stored, wall thickness of the
container, surface area of the container, and temperature. For example, in the case of
polyethylene, high permeation rates are observed for propane and isobutane because of the
chemical similarity to polyethylene and the low molecular weight of these gases.
Because of the large amount of time required for plastics to degrade, it is unlikely that
degradability affects the fate of VOC in plastic containers. The VOC in plastic containers still
intact once buried in a landfill will likely be released by permeation through the container wall
or leakage through failed seals.
Decomposition (e.g., corrosion) of metal containers as well as degradation of sealant
materials and subsequent leakage is likely play a role in the release of VOC. Chloride, which
is often present in municipal waste, is a strong promoter of corrosion in acidic media and will
attack steel and aluminum. Although aluminum is resistant to acids in general, it will deteriorate
rapidly in strong basic media. Presence of water in the landfill resulting from moisture in the
waste, precipitation, and/or leachate recirculation is expected to hasten corrosion of metal
containers. Although corrosion of the entire container is expected to occur over a long period
of time, VOC in the container will escape sooner through cracks and corroded seams.
Approximate decomposition times for tin-plated steel and aluminum cans exposed to the
air have been estimated at 100 years, and 100 to 500 years, respectively, depending on the
availability of sunlight and rainwater. In one study where metal cans were subjected to varying
environmental conditions (pH, temperature, and corrosivity), the shelf-life estimated for tin-
plated steel and aluminum containers ranged from 1 year to greater than 50 years.
6-3
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Most glass containers will be broken either in the compactor truck before the container
is placed in a landfill or as it is being placed or subsequently compacted and crushed. It is
possible, however, that some consumer product glass containers will remain intact once placed
in a landfill. Under such circumstances, release of VOC from glass containers depends on
factors similar to those for metal and plastic containers, as most glass containers use either a
metal or plastic top to contain and seal the product. Although glass containers are practically
non-degradable, the top may degrade or corrode and eventually allow VOC to be released.
6.1.2.3 Physical and Chemical Properties of VOC
In addition to landfill operating practices and product packaging characteristics, the fate
of a VOC in consumer products discarded in landfills is dependent on the specific physical and
chemical properties of the VOC. Volatile organic compounds with high vapor pressures (i.e.,
high volatility) will be released more readily than those with low vapor pressures. Also, VOC
with high permeabilities will escape from plastic containers more readily than those with low
permeabilities. Volatile organic compounds with high solubilities will tend to dissolve in the
landfill leachate and be released to the air more slowly than nonsoluble VOC with similar rates
of volatilization. Also, prior to release from a product container, some VOC in a specific
formulation may degrade to other VOC or non-VOC. This will occur over a period of time, as
most formulations are characterized by shelf-life or date of expiration.
Once residual VOC are released from product containers as a result of crushing and
compacting, leakage, corrosion, or permeation, there are five major mechanisms that can take
place within the landfill:
Volatilization,
Absorption,
Adsorption,
Chemical reaction, and
Biodegradation.
Mass transfer processes, including convection, diffusion, and displacement, facilitate these
mechanisms by moving of VOC within the landfill. For municipal landfills, landfill gas
convection is by far the predominant transport mechanism. As it flows through the refuse,
landfill gas sweeps vapors present in the landfill to the surface. In addition to these transport
processes, other activities may also result in transport of VOC to the landfill surface. Examples
include methane gas explosions and excavation of inactive or closed landfills.
The potential for each of the mechanisms listed above is dependent on the physical and
chemical properties of the VOC (e.g., physical state, vapor pressure, molecular weight,
solubility, adsorption characteristics, reaction potential) and the prevailing environmental
conditions within the landfill (e.g., moisture content, pH, temperature, soil characteristics, age
of refuse, and presence of bacterial).
6-5
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Major factors affecting volatilization of VOC in consumer product residuals following
release from product containers include:
• Concentration of the individual compound in the landfill,
• Properties of the individual compound (e.g., physical state, vapor pressure), and
• Landfill conditions (e.g., temperature, moisture content).
Volatilization of a compound is controlled by the equilibrium between the vapor and liquid
phases within the landfill system. Organic compounds in a landfill will evaporate until vapor
concentration equilibrium is reached at the landfill temperature and pressure. Higher
temperatures and lower pressures in the landfill will yield higher volatilization rates. Also,
higher vapor pressures of consumer product ingredients will yield higher volatilization rates.
An alternative pathway for VOC in a landfill following release from product containers
is absorption in the water in the surrounding medium. Potential sources of water are
groundwater or leachate recirculation. The primary factor that determines the potential for
absorption is the solubility of a VOC in water. For example, VOC with a high vapor pressure
(e.g., low molecular weight paraffins) are insoluble in water and will remain in vapor form,
whereas aromatic hydrocarbons are much more soluble in water. Other factors that affect the
absorption rate include relative concentrations in vapor/liquid phases and temperature. Also,
the presence of slightly soluble compounds (e.g., chloroform, benzene, alcohols) will enhance
the solubility of other VOC.
The VOC volatilization rates following absorption in water will be determined by the
vapor pressure and solubility of the compound and temperature of the medium. Compounds
with higher vapor pressure-to-solubility ratios will volatilize more rapidly. Also, higher
temperatures and lower pressures in the landfill will enhance vaporization rates.
Adsorption onto solids within the landfill is another pathway for VOC released from
product containers. The potential for this pathway is dependent on the adsorptive characteristics
of the VOC with respect to different types of solids and soils present in the landfill. For
example, high-molecular-weight and low-vapor-pressure VOC are likely to be adsorbed on soils,
as has been observed for halogenated hydrocarbons and some paraffins. As in the case of
volatilization following absorption in water, the potential for desorption or evaporation of VOC
from the soil or solid surface will depend on temperature and pressure in the landfill.
Chemical reaction between VOC released from different product containers is a possible
mechanism for production and/or destruction of VOC. These reactions may occur as a result
of contact .between reactive wastes placed in the landfill or reactive gases generated in the
landfill. Reactions with other wastes can speed, slow, or end the volatilization process. The
primary factor affecting the rate of chemical reaction is the composition of the refuse in the
landfill. For example, 1,1,1-trichloroethane (not defined as a VOC) will degrade into 1,1-
dichloroethene and possibly further into vinyl chloride in the presence of bare aluminum.
Possible chemical reactions are also affected by the landfill temperature and pH, but only if the
reactive compounds are present. Higher temperature can result in either increased or decreased
reaction rates.
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Higher-molecular-weight organic constituents in landfill wastes may be decomposed by
naturally occurring bacteria. The product of this decomposition can be a lower-molecular-weight
constituent with a higher vapor pressure or volatility. For example, it has been shown that
microbial involvement causes trichloroethylene to degrade to 1,2-dichloroethylene.
Biological decomposition of one organic compound into another is affected by the
composition of the landfill refuse and the landfill conditions (i.e., temperature, pH) supporting
biological activity. The best overall indicator of biological activity is the rate of landfill gas
generation. Landfill gas, consisting primarily of methane and CO2 (approximately 50/50 split)
with small amounts of VOC, is produced by microorganisms in the landfill under anaerobic
(without oxygen) conditions.
Factors that affect biodegradation rate include:
Refuse composition,
Refuse moisture content,
Refuse age,
Landfill temperature, and
Landfill pH.
Biological degradation is a potential pathway for a majority of the VOC of interest in this
study, with the exception of certain chlorinated VOC that are toxic to the bacteria in the
landfill. 1 * Biodegradation of consumer product residual VOC may be expected to be significant
for approximately the first 6 years, as biological activity in a typical landfill peaks within 6 years
of initial waste placement and declines steadily afterwards.
6.1.2.4 Emission Controls and the Fate of Consumer Product VOC in Landfills
Whether a landfill has a gas emission collection and treatment system (e.g., flares,
turbines, internal combustion engines) in-place will have an impact on the extent to which
VOC's from consumer products in landfills will be emitted to the air. The collection efficiency
of a collection system as well as the VOC reduction effectiveness of the treatment system will
affect the extent to which VOC emissions are reduced. Landfills with well designed gas
collection and treatment systems can eliminate about 50 to 60 percent of the VOC emissions to
the air.
The two basic options for controlling and treating landfill gas are combustion and
purification. Combustion control can be applied with or without energy recovery. Controls that
do not involve energy recovery include flares and afterburners. Options that involve energy
recovery include gas turbines, internal combustion engines, and boiler-to-steam turbine systems,
all of which generate electricity from combustion of landfill gas.
Purification techniques (adsorption, absorption, and membranes) process raw landfill gas
into pipeline-quality natural gas. All purification techniques involve removal of water before
removing carbon dioxide (CO2). The water is removed by either absorption with glycols or
adsorption with silica gel, alumina, or molecular sieve. The nonmethane hydrocarbons removal
method depends on the CO2 removal technique chosen and the composition of the landfill gas.
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Usually the same techniques used for CO2 removal are also used to remove nonmethane
hydrocarbons by simply adding an extra absorption, adsorption, or condensation step. Standard
natural gas pipelines generally do not accept halogenated compounds and sulfur derivatives.
Consequently, the removal of these compounds from landfill gases is a significant part of process
design.
The proposed new source performance standards (NSPS) for landfills (scheduled for
promulgation in August 1995) will require certain new landfills to install gas collection systems
and combust the captured gas. It is estimated that these regulations will reduce VOC emissions
from new landfills by approximately 70 percent. This, in turn, will have an effect on the
amount of VOC's ultimately emitted from consumer products that enter landfills.
Although an increasing number of landfills employ collection systems, the EPA was unable
to determine what portion of discarded consumer products are disposed of in landfills with
controls in place. Consequently, no adjustment to emission estimates could be made to account
for the fate of consumer product VOC in landfills.
6.1.3 Conclusions of the landfill ]Fate Study
The major findings of this study are summarized below. In reviewing these conclusions,
it is important to consider the limitations and the scarcity of the information available for use
in this study.
• There is limited information available on the potential fate mechanisms for VOC in
consumer product residuals placed in municipal landfills. A large portion of the
information identified is qualitative in nature and derived from studies conducted in
environments other than those representative of subsurface or municipal landfill
environments.
• Landfill operating practices (e.g., landfilling methods, the use of liners, the use of
covers), product packaging characteristics (e.g., metal, glass, plastic), and physical
and chemical properties (e.g., volatility, solubility, adsorptivity) of the VOC
determine how and when the residual VOC in a consumer product container will be
released following placement in the landfill.
• Once the VOC in consumer product residuals are released, their ultimate fate is
dependent on the specific physical and chemical properties of the VOC and the
environmental conditions (e.g., temperature, moisture content, pH) within the
landfill.
• Based on the review of available information, the majority of the VOC/ VOC groups
included in this study are likely to be affected by three mechanisms in the landfill:
volatilization, absorption, and biodegradation. Adsorption and chemical reaction are
likely to be less significant fate mechanisms.
6-8
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TABLE 6-1 ULTIMATE FATE OF VOC AND VOC GROUPS
Emitted
to Air
asVOCa
Emitted
. to Air
asnon-VOC*
Absorbed
in Water
Adsorbed
on Solids
Paraffins and Isoparaffins
Aliphatic Hydrocarbons
Butane
Isobutane
Petroleum Distillates
Propane
VM&P naphtha
Aromatic Hydrocarbons
Toluene
Xylene
Chlorinated Hydrocarbons
Alcohols
Ethanol
Isopropanol
Ethylene Glycol
Propylene Glycol
jCetones
Acetone
aVia volatilization, evaporation, and desorption.
t>Via chemical reaction and/or biodegradation.
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6.2 FATE OF CONSUMER PRODUCT VOC IN WASTEWATER
Many emissions inventories assume that all VOC in consumer products will eventually
volatilize to the air. However, the VOC in some products, such as soaps, laundry detergents
and household cleaners, may be combined with water before being completely or even partially
volatilized. This study summarizes the fete of VOC associated with consumer products once
they are introduced into the wastewater treated by publicly-owned treatment works (POTW's).
It should be noted that no quantitative data have been developed that estimate the portion of a
given product that actually gets washed down the drain.
6.2.1 Consumer Products MffSt LJKffly tQ Enter WflStCWflter
Recent EPA studies aimed at expanding the available information describing formulation
data and VOC emissions potential from consumer products have yielded formulation data for
nearly 50 product categories. These categories include both aerosol and nonaerosol products and
vary greatly in their VOC content. In addition, the typical use and disposal of these consumer
products play a critical role in determining the contribution of a specific product category to
domestic wastewater.
The typical use and disposal practices associated with each of these consumer product
categories were studied to determine which of the categories may have a significant impact on
domestic wastewater. The categories were rated as follows, based upon the probability of
discharging VOC into wastewater:
Rating Rationale
Low Any product category not typically used or disposed of by
means of a sanitary drain or any product category with
formulation data void of VOC.
Moderate Any product category that requires clean-up in water or
any product used in a manner that residual components
would be removed by washing or bathing.
High Any product category that requires use or disposal in a
sanitary drain.
A list of the consumer product categories evaluated during this study and their potential for
entering the wastewater stream is provided in Table 6-2.
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TABLE 6-2
POTENTIAL FOR CONSUMER PRODUCTS TO ENTER WASTEWATER
Product Type
Adhesives (Consumer)
Air Fresheners
Anti-static Sprays
Auto Antifreeze
Auto Cleaners
Brake Cleaners
Carburetor & Choke Cleaners
Carpet Deodorizers
Car Polishes & Waxes
Caulking & Sealing Compounds
Engine Degreasers
Engine Starting Fluids
Hair Care Products (hair sprays)
Herbicides & Fungicides
Insect Sprays
Lubricants & Silicones
Moth Control Products
Paints, Primers & Varnishes
Prewash Stain Removers
Shoe Polishes
Starch & Fabric Finish
Undercoatings
Waxes & Polishes
Window & Glass Cleaners
Windshield Deicer
Animal Insecticides
Colognes, Perfumes & Aftershaves
Floor Waxes & Polishes
Hair Removers
Hair Spray
Insect Repellents
Metal Cleaners & Polishes
Oven Cleaners
Personal Deodorants
Pharmaceuticals
Rug & Upholstery Cleaners
Spot Removers
Styling Mousse
Suntan Lotions
All Purpose Cleaners
Disinfectants
Drain Openers
Liquid Detergents
Shaving Lathers
Tile & Bathroom Cleaners
Product
Form*
A/N
A/N
A/N
N
A/N
A
A
N
N
A/N
A
A
A/N
A/N
A/N
A/N
A/N
A
A/N
A/N
A
A/N
A/N
A/N
A/N
A/N
A/N
N
A
A/N
A/N
N
A/N
A/N
A
A/N
A/N
A
A
A/N
A/N
N
N
A
A/N
Potential for VOC
Entering Wastewater
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
High
High
High
High
High
High
*A = aerosol, N = nonaerosol and A/N = both aerosol and nonaeroaol products.
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6.2.2 Principal Product Ingredients Entering Wastewater
Formulation data for each of the consumer product categories established as "High" or
"Moderate" in their potential to reach domestic wastewater were reviewed. Whenever multiple
formulation data within a specific product category were available, a "typical" product formula
was developed by assuming equal market share for each of the formulations and averaging the
specific constituents across each formula. If formulation data were only provided in ranges, the
upper extremes of all reported ranges were used to identify potential VOC constituents.
A list of target VOC constituents contributing to the composition of domestic wastewater
through the use or disposal of consumer products was developed by compiling the VOC
constituent data from the "typical" product formulation for each category. Detailed quantitative
determinations about the amount of these materials discharged into the wastewater were not
attempted since national consumption data and market share information were not available for
specific product formulations in all product categories.
Analyzing a product's potential to enter wastewater and reviewing either actual product
formulation data or generic formulations identified five compounds that could enter wastewater
from consumer products at potentially significant levels. These five compounds are ethanol,
isopropanol, a-terpineol (pine oil), propylene glycol and Stoddard solvents. The VOC grouping
called Stoddard solvents is defined as a mixture of 85 percent n-nonane and 15 percent trimethyl
benzene isomers and is representative of solvents that are actually a complex mixture of various
compounds (e.g., mineral spirits). Table 6-3 lists each compound, the consumer product
categories in which it is found, the potential for entering wastewater and the average weight
percent of the compounds in the formulation of each product.
The Stoddard solvents group and isopropanol are the only compounds listed in Table 6-3
which have the potential to volatilize rapidly from wastewater. A standard measure of the
potential for a compound to volatilize from water is the Henry's law constant (H). H is equal
to the vapor pressure of a compound in atmospheres (atm) divided by a compound's solubility
in water in moles per cubic meter (mol/nr) and is expressed in units of atm-nr/mol. The
potential for a compound to be volatile in water is characterized as follows:
• Low if H is less than 1 x 10~7 atm-m3/mol, the substance is less
volatile than water and its concentration will increase as water
evaporates.
• Moderate in the range of 10"7 < H < 10~5 atm-m3/mol, the
substance volatilizes slowly at a rate dependent on H with the gas-
phase resistance dominating the liquid-phase resistance by a factor
of ten. Therefore, the rate is controlled by slow molecular
diffusion through air.
• High when H is greater than 10~5 atm-nr/mol, volatilization from
water is rapid.°
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Henry's law constants for ethanol, isopropanol, a-terpineol, propylene glycol and
Stoddard solvents and the potential for each to volatilize from water are listed in Table 6-3.
As these data show, two compounds have both the potential to enter wastewater from
commercial/consumer products and the potential for significant volatilization: Stoddard solvents
and isopropanol. Ethanol and propylene glycol are moderately volatile, while a-terpineol is
essentially non-volatile.
Analyzing a product's potential to enter wastewater and reviewing either actual product
formulation data or generic formulations identified five compounds that could enter wastewater
from consumer products at potentially significant levels. These five compounds are ethanol,
isopropanol, alpha-terpineol (pine oil), propylene glycol, and Stoddard solvents.
TABLE 6-3
VOLATILITY OF CONSUMER PRODUCT VOC IN WATER
Compound
Ethanol
Isopropanol
« -Terpineol
Propylene Glycol
Stoddard Solvents
'The value for Stoddard Solvents was estimated
benzene.
Henry's Law Constant
(atm-nr/mol)
3.03 x 10'5
l.SOx 10"4
3.55 x 10'7
1.50 x 10'6
8.49s
from a mixture 85 percent n-nonane
Potential for
Volatility in Water
Moderate
High
Moderate
Moderate
High
and 15 percent trimethyl
The categories of consumer products that are most likely to be disposed of into a
municipal or community sewer system were analyzed. The analysis included:
• Determining the potential for products from each category to enter the sewer
• Estimating the national annual consumption of each product type
• Determining the percent by weight of each VOC species in each product type
• Calculating the annual consumption of each VOC species for each product type
• Estimating the daily per capita usage of each VOC species by product type
• Calculating the daily per capita releases of each VOC species down-the-drain
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The product categories Liquid Dish Detergent, Liquid Laundry Detergent, All-Purpose
Cleaners, Tile and Bathroom Cleaners, and Shaving Lather were all assumed to be disposed of
down-the-drain through use with water and were designated as having a high potential for
entering a POTW. The product category Disinfectants was assumed to be used in a manner
likely for down-the-drain disposal for liquid formulations, but with only moderate potential for
aerosol formulations (e.g., aerosol disinfectants used as room deodorizers and/or as surface
sanitation). The remaining product categories included in the analysis for this effort (Hair
Sprays, Styling Mousse, Insect Repellents, Aftershaves, Oven Cleaners, Perfumes and Colognes,
Suntan Lotions and Animal Insecticides) were assumed to have a moderate potential for entry
into the wastewater stream.
6.2.3 Pathways for VOC Release from Municipal Wastewater Systems
Components of the municipal wastewater system include a sewer collection network,
treatment facilities and an outfall and/or disposal facility, depending on the ultimate fate of
various wastes. A typical system has at least one POTW; the expression "POTW" specifically
identifies the treatment operations. However, the term POTW has often been used to encompass
all functions of the municipal wastewater system. To avoid confusion, this discussion presents
each major functional component of the system (i.e., collection, treatment and disposal).
Location, size and configuration of the wastewater system are determined by the location
of sources and the nature and magnitude of waste constituents. No single system uses all of the
processes presented here: some combination of the devices and processes discussed in the
following pages is employed to meet the particular treatment needs and capital limitations.
Wastewater is collected or received from several sources including homes, institutions,
industries, stormwater, and infiltration. The collection and conveyance system encompasses
collection from the point of waste generation to entrance into the wastewater treatment works,
including the various drains, sewers and pumps necessary to deliver the water to the treatment
system. However, municipalities maintain and operate only the conveyance network from the
street sewer to the treatment plant.
The wastewater collection process actually starts where the wastewater is generated, most
often in buildings. Plumbing fixtures empty into batteries of horizontal drains and vertical stacks
which discharge into the building drain. Approximately five feet from the building, this drain
becomes the building sewer which empties into the street sewer.
Other necessary building drainage features include traps and vents. Traps hold a water
seal that obstructs and prevents foul odors and noxious gases, insects and vermin from passing
through the drainage pipes and sewers into the building. Vents to the atmosphere are used to
equalize the difference in air pressure and prevent failure of the water seal caused by the
entrainment of air in the plumbing fixtures.
Gravity sewers are designed as open channels flowing partly full, or at most, just filled,
using free or gravity flow. Sewer grades are constructed steeply enough to maintain the
wastewater flow at self-cleaning velocities of 2 to 2.5 feet per second. Except in large sewers,
manholes are built at all junctions with other sewers, at all changes in direction or grade, and
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between 300 and 500 feet apart at a minimum. Construction materials for gravity sewers include
vitrified-clay, asbestos-cement pipes and fiberglass reinforced plastic.
Where conditions are not suitable for gravity flow, a pumping or lift station can lift
flows through a force main into a higher-lying gravity sewer. The lift station is an arrangement
of pumps, electric motors, sets, piping, valves, strainers, controls and alarms with a ventilation
•fan, sump pump, dehumidifier, lights and space heater assembled in an enclosed structure.
Other optional equipment includes pressurized sewers and vacuum sewers. (Pressurized sewer
force mains full flow and are laid parallel to the ground surface.) Some system designs have
provisions for comminuters or grinders and pumps to discharge nonclogging wastewater from
individual systems through pressurized pipes.
The potential for VOC to be emitted from a conveyance system has been discussed in the
literature. Mathematical models based on fluid mechanics, air exchange rates, drag at the air-
wastewater interface, barometric pressure gradient, temperature differences, "breathing losses"
due to changes in liquid level and forced ventilation have been proposed. The consensus in the
literature is that releases from conveyance systems are rather limited.
The potential for releasing VOC is expected to be greatest in the first physical treatment
processes in a POTW for two reasons: the amount of VOC in the wastewater is greatest as the
waste stream first enters the plant and the increase in surface area and turbulence associated with
primary treatment will allow greater volatilization than would be expected in the conveyance
system. However, physical treatment processes occurring after biological treatment are expected
to play a less important role since most VOC would be greatly reduced by the time wastewater
reaches these processes.
The potential for removal of VOC without creating emissions is greatest with biological
treatment. This potential is due to microbial organisms that rapidly consume organic
compounds, turning them into cellular material, and adsorption of organics to the highly organic
sludge. However, the greater surface area found in the bubbles in aerated activated sludge
basins and on the surfaces of trickling filters creates a high potential for volatilization.
Therefore, the potential for the VOC to be consumed by the microbial flora of the biological
treatment process is tempered by the potential for greater volatility due to increased air-water
interface area.
The potential for VOC emissions from treated wastewater in outfall and disposal
processes is determined by the process type and the efficiency of the biological treatment used
to remove the VOC. Emissions would be expected to be greater in aeration processes than in
a process such as landfilling of sludges and slurries.
6.2.4 Computer Models for Estimation of Fate of VOC in Model POTWs
This section reviews the methods available to estimate the fate of VOC in POTW's. The
VOC of interest in this study include ethanol, isopropanol, or-terpineol (pine oil), propylene
glycol and Stoddard solvents. The configurations of three model POTW's are also considered
in this section of the report.
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There are three basic approaches for estimating the fate of individual and total VOC
associated with consumer products within POTW's:
• Field measurement of VOC emissions in the different units of the
POTW plants
• Performing of an overall mass balance in the plant by calculating
the difference between the VOC mass present in the influent and
effluent streams
• Utilization of mathematical models with algorithms for estimating
VOC removal rates due to volatilization, biodegradation, and/or
adsorption to solids
The first approach is impractical due to limitations in ambient VOC monitoring
techniques for some processes. Additionally, day-to-day differences in wastestreams and
conditions make any measurements difficult to use. The second approach is certain to
overestimate ambient VOC emissions, since it does not account for other competing VOC
removal mechanisms such as biodegradation and adsorption to solids and biomass. The third
approach is less expensive and faster than actual field measurements and allows for a better
estimate of the fate of VOC than the overall mass balance approach. The third approach, using
computerized mathematical models, was adopted for this study.
Documentation on existing models for waste treatment facilities and (conveyance systems
(sewer lines) was collected and reviewed to determine the applicability of each model to this
project. When documentation of the model was not available, as in the case of the conveyance
system, the model was evaluated based on information taken from published studies using the
model. »2 Three comprehensive models were identified for the waste treatment facilities, one
model was identified for the conveyance system and two alternative models for some POTW
treatment units were identified. Table 6-5 shows a summary of the models identified and the
corresponding offices responsible for the model's availability and/or development.
The following criteria were used to evaluate the models:
Removal mechanisms and treatment units modeled
Input requirements and the availability of input data
Output provided by the model and the degree of conservatism exhibited
Model testing and validation
Model advantages and limitations
Applicability to the POTW project
Three comprehensive models applicable to VOC emissions from POTW's were evaluated
in this study: BASTE, SIMS, and CHEMDAT7. Each has certain limitations with respect to
its ability to calculate VOC emissions from POTW's.
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TABLE 6-4
SUMMARY OF THE MODELS IDENTIFIED
Model Party Responsible for Model
Availability and/or Development
Surface Impoundment Modeling EPA/Control Technology Center
System (SIMS) version 2.0 Radian Corporation
CHEMDAT7 EPA/Office of Air Quality Planning and
Standards
Bay Area Sewage Toxics Emission Civil Eng. Dept., Univ. of California, Davis,
(BASTE) Model CH2M-Hill/Bay Area Air Toxics Group
Corsi Modela Civil Eng. Dept., Univ. of California, Davis
Pincince Model Camp Dresser & McKee, Boston, MA
Reaeration Model Tsivoglou and Neal (1976) WPCF 48(12):2669
"This model was developed by Dr. Richard Corsi using an adaptation of the Parkhurst-Pomeroy model to
predict oxygen absorption in sewers. This model is not documented.
The SIMS and CHEMDAT7 models use many of the same algorithms. Neither model
allows changes in temperature or changes in the compound's chemical and physical properties.
The effect of these changes on the emission rates of compounds with low Henry's law
coefficients, such as alcohols, can be significant. The models also perform steady-state mass
balances, not allowing fluctuations on pollutant inlet concentration and flow rate, and assume
that the wastewater in the impoundments is well mixed, which is not the case with sedimentation
tanks and aeration basins. Finally, they do not include algorithms to calculate the adsorption
of VOC on solids and the emissions from units comprising the head works.
The BASTE model does allow for temperature changes and will model all aspects of a
POTW, including split flows and multiple processes. However, BASTE is limited in the
chemicals it will allow to be input into the model, and the VOC analyzed in this study could not
be used with BASTE.
Despite their limitations in estimating VOC emissions from a POTW, either SIMS or
CHEMDAT7 could have been used in this effort. However, the SIMS model presented certain
advantages over CHEMDAT7 (discussed below) and was considered more appropriate for this
study. Since the SIMS model was easier to use and manipulate, had a shorter execution time,
and included algorithms to calculate emissions from weirs and other wastewater collection
devices, it was utilized for this study.
P6.2.4 Results of Modeling of VOC Fate in Wastewater Processes
The fate of each of the five selected VOC was evaluated using computerized
mathematical models. The approach selected for this analysis was based on a review of
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currently available modeling techniques for VOC removal from POTW's. The estimated
emissions of VOC from the conveyance system (sewer lines) leading to the model POTW's were
based on Corsi's studies of VOC emissions in hypothetical sewer reaches. The results from
modeling the conveyance system were used to provide the inputs for the model POTW's. The
estimations for VOC removal from the treatment units of model POTW's relied on a
combination of three models: SIMS, the Trivoglou and Neal reaeration model, and the Pincince
model for clarifier weir loss. The modeling of both the sewer system and the POTW's was
performed for a steady influent flow and VOC concentration.
The steps involved in estimating VOC removal from a POTW included:
• Acquisition and preparation of input data
• Estimation of VOC losses in the sewer lines using the results of
the Corsi studies
• Estimation of VOC losses at individual units in the POTW using
a combination of three models: SIMS, the Pincince algorithms for
clarifier weirs, and the Tsivoglou and Neal reaeration model for
headworks processes
• Analysis of the results obtained from the modeling
The loss rates for each selected VOC were calculated for three POTW size
configurations, each with a different flow rate. Additionally, three cases were applied to each
POTW configuration:
• Case 1: default SIMS algorithms for clarifier weirs used
with influent VOC concentrations at values
calculated from Section 2
• Case 2: SIMS algorithms used with influent VOC
concentrations at two times the calculated values
• Case 3: Pincince algorithms for clarifier weirs were used
in place of the SIMS algorithms with influent
VOC concentrations at calculated values
Nine permutations among the three sizes and three cases were used with the model
POTW's for each of the five compounds. A summary of the modeling results is presented in
Table 6-5.
The greatest variability in removal rates between the selected VOC was driven by
emissions to air. This variation in removal rates was found in the model conveyance systems
and with several processes within the model POTW's. Within the conveyance systems the
compounds with low Henry's law coefficients (i.e., alcohols) were stripped at a much lower rate
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than Stoddard solvents, which have a very high tendency to volatilize. The percentage of total
VOC removal for the small sewer line was approximately twice the percentage removal for the
medium and large sewer lines. This could be explained by the larger gas volume above the
wastewater surface, which dominates the transfer process, associated with shallow flows and
longer residence time in the system.
Within the model POTW's, the less volatile compounds (ethanol, propylene glycol, and
a-terpineol) showed greatest potential for air emissions at the primary clarifier weir when the
SIMS algorithms were used (Cases 1 and 2). Isopropanol had the potential for emissions at both
the primary clarifier weir .and the aeration basins. However, the overall removal of alcohols,
when compared between model POTW's, was similar within each case, since biodegradation was
the main removal mechanism for this chemical group.
Substitution of the Pincince clarifier weir algorithms for the default SIMS weir algorithms
(Case 3) resulted in changes in emissions to air which differed from the other two cases and
were dependent upon the nature of the compound being modeled. There were practically no
changes in the air emissions of Stoddard solvent. This model compound is highly volatile and
was stripped in the aeration basins for the small POTW and in the grit chambers for the medium
and large POTW's (i.e., before the clarifier weirs were reached). However, there were
noticeable reductions in the emissions of the less volatile compounds, such as the alcohols. The
reduction in emissions calculated using the Pincince algorithms seemed to be related to the
Henry's law coefficient for the compound being modeled. The greatest reduction in air
emissions at clarifier weirs between Case 3 and Case 1 results was seen for a-terpineol (94
percent difference) and the lowest was seen for isopropanol (47 percent difference). These
differences are most related to the Henry's law coefficient for these compounds.
The results from the Pincince algorithms (Case 3) for VOC emissions from clarifier weirs
were found to be closer to the results reported in other studies than those predicted by the default
SIMS algorithms. Therefore, Case 3 results have been used in the remainder of this discussion
of results.
Results of the VOC air emissions estimates and corresponding percent mass removal by
biodegradation and emissions to air for each case studied are presented in the report. The effect
of doubling the initial VOC concentration was to increase the air emissions by the same factor
in each of the model POTW's. This could be explained by the fact that most of the equations
used in the modeling process are directly proportional to the initial VOC concentration.
The overall percent removal, however, remained virtually the same. The overall VOC
air emissions from the use and disposal of consumer products were calculated using the results
obtained when the Pincince clarifier weir models were used in the POTW's. The total VOC air
emissions for the small sewer line and POTW were estimated at 0.1171 tons/yr: 31 percent
emitted during the wastewater transportation to the POTW and 69 percent emitted at the POTW
itself. For the medium and large sewers and POTW's, the total VOC air emissions were
1.386 tons/yr and 16.09 tons/yr, respectively. Approximately 14 percent of the VOC was
emitted at the sewers and 86 percent at the POTW's.
Stoddard solvent was removed 100 percent in the three sewer-POTW systems, mainly
through volatilization. The total removal for the alcohol compounds was approximately
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99 percent for ethanol, 98 percent for alpha-terpineol, 91 percent for isopropanol, and 90 percent
for propylene glycol. Biodegradation was the main removal mechanism for this group,
accounting for over 96 percent of the total removal for ethanol and o-terpineol; 87 percent of
the total removal for propylene glycol; and 76 percent of the total removal for isopropanol.
6.2.5 Conclusions of the Wastewater Fate Study
Consumer products were evaluated to determine which of the categories may likely enter
domestic wastewater. All categories were rated as low, moderate, and high based upon the
probability of discharging VOC into wastewater. The product categories found to have the
highest potential to discharge to wastewater include liquid dish detergent, liquid laundry
detergent, all-purpose cleaners, tile and bathroom cleaners, and shaving lather. They were all
assumed to be disposed of down the drain through use with water and were designated as having
a high potential for entering a POTW. Liquid formulation disinfectants were assumed to be used
in a manner likely for down the drain disposal, but aerosol formulations have only a moderate
potential. Hair sprays, styling mousse, insect repellents, aftershaves, oven cleaners, perfumes
and colognes, suntan lotions, and animal insecticides were assumed to have a moderate potential
for entry into the wastewater stream.
The VOC emissions can occur at any step in wastewater treatment where the wastewater
comes in contact with air. The greatest potential is in processes where turbulence increases the
water-air interface. The potential for releasing VOC is expected to be greatest in the physical
treatment processes. These processes include screening, sedimentation, flotation and filtration
to remove materials which can damage or foul subsequent treatment and process equipment.
There are two reasons for this high potential: the amount of VOC in the wastewater is greatest
as the waste stream first enters the plant and the increase in surface area and turbulence
associated with primary treatment will allow greater volatilization than would be expected in the
conveyance. The potential for removal of VOC without creating emissions is greatest with
biological treatment. This potential is due to microbial organisms that rapidly consume organic
compounds, turning them into cellular material, and adsorption of organics to the highly organic
sludge. However, the greater surface area found in the bubbles in aerated activated sludge
basins and on the surfaces of trickling filters creates a high potential for volatilization.
Therefore, the potential for the VOC to be consumed by the microbial flora of the biological
treatment process is tempered by the potential for greater volatility due to increased air-water
interface area. There is also some potential for VOC emissions from treated wastewater in the
wastewater outfall and sludge disposal process. Emissions would be expected to be greater in
aeration processes than in processes such as landfllling of sludges and slurries.
Fate analyses were reported for specific classes of VOC in the consumer product
categories addressed by this evaluation. For aliphatic alcohols, biodegradation represents the
principal removal mechanism for simple alcohols in wastewater. Glycols are also primarily
removed by biodegradation. Empirical rules for biodegradation also suggest that straight-chained
alkanes are highly susceptible to microbial degradation and probably do not enter the domestic
wastewater stream in significant quantities. In addition, these compounds are generally used as
propellants and volatilize during product use. They would therefore, not be found in wastewater
streams. Most chlorinated aliphatic hydrocarbons and aromatic compounds are removed by
volatilization. Petroleum products are removed by biodegradation. In general, biodegradation
6-20
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is the principal removal mechanism for most of the selected VOC from consumer products in
wastewater, with the exception of Stoddard solvents, which are mostly air-stripped in aeration
basins.
The fate of each of the five selected VOC identified as having the potential to enter the
wastewater stream in significant quantities was evaluated using computerized mathematical
models. The approach selected for this analysis was based on a review of currently available
modeling techniques for VOC removal from POTW's.
TABLE 6-5
FATE OF SELECTED CONSUMER PRODUCT VOC IN WASTEWATER
Compound
Ethanol
Isopropanol
Stoddard Solvents
Propylene Glycol
a-Terpineol (pine oil)
Total (weighted)
Percent
Emitted
3.7
14.6
100.0
3.0
0.7
12.2
Percent
Biodegraded
95.4
75.5
0.0
86.7
97.1
86.3
Percent Remaining
in Effluent
0.9
9.9
0.0
10.3
2.2
1.5
1. Corsi, Richard L. et al. Assessment of the Effects of Ventilation Rate on VOC
Emissions from Sewers. Presented at the 82nd Annual Meeting of the Air & Waste
Management Association. Anaheim, CA. June 1989.
2. Corsi, Richard L. Prediction of Cross-Media VOC Mass Transfer Rates in Sewers
Based Upon Oxygen Reaeration Rates. Presented at the 82nd Annual Meeting of the
Air & Waste Management Association. Anaheim, CA. June 1989.
6-21
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CHAPTER 7
ECONOMIC INCENTIVES TO REDUCE VOC EMISSIONS
FROM CONSUMER AND COMMERCIAL PRODUCTS
This chapter presents a summary of the EPA's preliminary assessment of the feasibility
and desirability of employing federal economic incentive programs to reduce VOC emissions
from the use of consumer and commercial products. Section 183(e)(4) lists "..economic
incentives (including marketable permits and auctions of emissions rights).." among the systems
of regulation authorized to be used to achieve emission reductions from consumer and
commercial products. This investigation of economic incentives was undertaken to evaluate the
desirability of different regulatory strategies that may be appropriate under §183(e).
The principal tasks of the study are to examine alternative economic incentives and to
compare them to a hypothetical command-and-control program. VOC content standards, which
would consist of product-specific limitations on maximum VOC content (grams of VOC per unit
of product). It is the basis of comparison because the ultimate purpose of this investigation is
to search for the most desirable instrument in the set of potentiahinstruments, which obviously
would include instruments based on command-and-control.
The purposes of comparison are to determine how well the instruments accomplish
certain policy objectives and to appraise their ability to cope with the complexities inherent in
the task of environmental regulation. The specific bases of comparison are the following:
program costs and initial information requirements when effects are uncertain.
monitoring and enforcement.
flexibility in distributing the economic impacts of regulation.
adaptation to economic growth.
incentives for technological innovation and diffusion, and
unintended damages.
These criteria ensure a fairly comprehensive examination of the issues involved in designing
environmental policy instruments. Further, a broad basis of comparison more fully reflects
differences between economic incentives and command-and-control approaches.
This report does not serve as the final assessment of economic incentive strategies to
reduce VOC from the many consumer and commercial products that may ultimately be
regulated. Rather, it serves as a general assessment of the most prominent economic incentives
for reducing air pollution, and it serves to set the stage for the future development of more
detailed and industry-specific economic incentives.
Economic incentives may be particularly appropriate for the control of VOC from
consumer and commercial products. The emissions source of concern is the use of the product
but not the manufacture. This aspect of the pollutant leads to the existence of a great many
small sources for which "end-of-pipe" control is practically infeasible. The products are very
diverse. The types of consumer and commercial products and product forms number in the
thousands. Product diversity reflects the adaptation of products to consumer demands, which
7-1
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vary from region to region and change from one year to the next. The core of the dynamics of
consumer and commercial product industries is product innovation-each year, manufacturers and
importers introduce hundreds of new products. In these circumstances, economic incentives may
have great advantages over command-and-control strategies, such as VOC content standards,
because (1) the Agency may need to accumulate less information on product technology and on
performance; and (2) manufacturers have more flexibility to find the best balance between
reducing VOC emissions and satisfying consumer demands. :
Many VOC have specific characteristics that influence die design of a regulatory
program. VOC are assimilative and uniformly mixed implying that emissions do not accumulate
in the atmosphere and the concentration of ozone is independent of the location of sources in the
airshed. Therefore, economic incentive programs need only to target total emissions of the
pollutant rather than ambient concentrations of ozone.
Emission fees and emissions trading are the economic incentive most commonly proposed
for the purposes of air pollution control. A comparison of these designs mates explicit the
requirement for the consideration of certain fundamental policy issues, including the tradeoffs
between: (1) certainty over the cost of emission reductions versus certainty over the quantity
of emissions reduced, (2) the cost of control emissions versus administrative, monitoring, and
enforcement costs, and (3) distributional flexibility versus the provision of incentives to advance
technology. This report examines these tradeoffs in some detail.
Emission fee programs can be used to obtain real and quantifiable reductions in the
emissions of VOC from consumer and commercial products. The basic rationale for these
programs (and economic incentive programs in general) is to bring the full "social cost" of using
VOC into the price of the product. A fee on the emission of VOC would increase the cost of
using the atmosphere as a waste sink. The fee would have the same effect as the prices for the
goods and services exchanged in conventional markets: for example, manufacturers would
economize on their use of VOC because the "price" of using VOC would be higher, just as they
would economize on the use of labor if wage rates were to increase.
products
Designing a fee program to reduce VOC emissions from consumer and commercial
ts presents many choices. Many of these design options are summarized in Table 7-1.
7-2
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Quantity-based emissions trading programs are alternative ways to generate economic
incentives to obtain real and quantifiable reductions in the emissions of VOC from the use of
consumer and commercial products. The two types of trading programs studied in this report
are marketable emission permit programs and emissions averaging programs. Particular
emphasis is given to emission permit programs because of their unique advantages and other
unique characteristics.
The distinguishing characteristics of marketable emission permit programs are inter-
source trading of emissions and the cap on the aggregate, absolute quantity of emissions. Unlike
emission fee programs, VOC content standards, and emissions averaging programs, the absolute
quantity of emissions is fixed in marketable permit programs. The restriction ensures the
achievement of the environmental goal regardless of changes in the economy including the
expansion of existing and entry of new sources (e.g., companies) of emissions. Emission
averaging programs also rely on emissions trading and are most cost-effective when trades occur
between companies, but they characteristically place an upper limit on emission rates instead of
total emissions. The nature of the environmental goal is an essential difference between
marketable permit programs and emissions averaging programs.
Table 7-2 summarizes many of the design options for marketable emission permit programs.
In all emission trading programs that allow external trades, companies have the incentive
to seek potential trading partners. Opportunities for trade exist when the incremental or
marginal cost of emission reductions differ in the industry. The consumer and commercial
products industry is diverse, and manufacturers very probably will reduce emissions through
unique combinations of product reformulation, packaging redesign, and reducing production.
Therefore the marginal cost of emission reductions is likely to vary from company to company,
and the company for which a reduction is more expensive will pay another company (i.e., one
with lower costs) to reduce emissions. The benefit to the former company is reduced costs, and
the benefit to the latter, increased profits.
Table 7-3 compares the performance of economic incentives and hypothetical VOC
content standards on the criteria listed above. Table 7-3 assumes that every program aims to
achieve the same environmental goal, a predetermined reduction in VOC emissions. The table
includes the most important variants of both types of economic incentives: emission fee
programs with and without rebates, and permit programs in which the EPA allocates permits to
existing sources through an ordinary auction, zero-revenue action, or grant. The ranking of each
program on a given criterion indicates relative performance and is discussed next.
Abatement Costs. In theory, marketable permit programs and fee programs will lead to
the least costly emission reductions. In practice, however, none of these strategies will likely
achieve the truly least cost solution that might be obtainable in a world of zero transaction costs
and perfect certainty. In marketable permit programs with freely granted permits, transaction
costs may restrict trading and hence reduce potential abatement cost savings, though costs of
obtaining the same level of emission reductions would never exceed those resulting from content
standards. Permit auctions may reduce the need for trading, but periodic auctions may impose
uncertainty costs. Similarly, fee programs with adjustable fee rates may impose planning
uncertainty or transition costs. Nevertheless, economic incentive strategies will generally result
in reduced abatement costs compared to content standards because economic incentives provide
7-4
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the flexibility to obtain emission reductions from the least costly sources.
Monitoring and Enforcement. For the purpose of comparison, nothing is lost by
assuming that the penalty for noncompliance and probability of detecting noncompliance ensure
a reasonable level of deterrence. With equal levels of deterrence, the comparison of policy
instruments is a matter of differences in the activities and hence costs of detecting
noncompliance. The economic incentive programs all require the collection of companies'
reports of VOC content in the regulated consumer and commercial products and report
verification; verification involves product sampling and reviewing product sales information.
Marketable permit programs also require the Agency to track permit holdings. VOC content
standards are less demanding than economic incentives because the Agency does not absolutely
need to obtain sales information and monitor compliance nor does it need to track permit
holdings. Sales information, however, would be necessary to monitor program performance.
Distributive Flexibility. At issue is not whether one pattern of distributive effects is
preferred to some other pattern but rather the dialogue over distributive considerations. The
ranking of policy instruments indicates the degree of flexibility to incorporate distributive values
into instrument design. Fee programs with rebates and marketable permit programs with freely
distributed permits or permits distributed through a zero-revenue auction may serve to minimize
adverse distributional impacts on industry.
Adaptation to Economic Growth. All instruments can adapt to the changes in the
economy that may strain the ability of the instruments to achieve the environmental goal, but the
quickness of the adaptation and the costs to the EPA and regulated companies differ
substantially. All permit programs adapt without action by the Agency because of the cap on
emissions and hence are ranked the highest.1 All fee programs, even those with formulas for
the automatic but potentially sluggish adjustment of the fee rate, are likely to require the EPA
to take corrective action when economic growth leads to an undesired increase in VOC emissions
in nonattainment areas. VOC content standards would require the EPA to tighten the standards
and, if new consumer and commercial products have appeared, to issue new standards;
adaptation is likely to be slowest and Agency expenditures greatest.
Incentives for Technological Change. The evaluations are sensitive to the incentives that
companies have to innovate, sell, and adopt cost-reducing technologies for reducing VOC
emissions from consumer and commercial products. All of the economic incentive strategies
promote technological innovation to a similar degree, but some strategies promote technological
diffusion more than others.
Unintended Damages. Narrowness in the design of traditional or economic incentive
regulatory programs may cause problems during implementation: intermedia transfer of
1 Permit banking requires a qualification of that judgment because aggregate emissions will
exceed the cap in a year when previously banked permits are withdrawn and used, everything
else equal. Nonetheless, without action by the EPA, the annual average emissions equals the
emissions cap.
7-6
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f
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1
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pollutants, increased VOC emissions due to inferior product performance, increased health risks,
and increased air pollution in some areas. These unintended consequences are possible with all
the policy instruments under review. Some of these potential problems, such as those due to
product performance, appear to be more probable and to have greater avoidance costs with
standards because companies have reduced flexibility to modify their products under the
restrictions imposed by standards.
Conclusion. Overall, economic incentive programs appear superior to VOC content
standards as strategies to reduce VOC emissions from consumer and commercial products.
However, content standards may still be preferable if monitoring and other implementation costs
are excessive.
The choice between traditional and economic incentive regulatory strategies is not
necessarily an all or nothing choice. Combination content limit/economic incentive approaches
are possible and may provide significant advantages, though these advantages need to be weighed
against the shortcomings they may create.
The optimal selection of a regulatory strategy will depend on the specific characteristics
of the universe of sources being regulated. For example, potential abatement cost savings,
administrative and monitoring costs, and distributional implications of employing economic
incentive strategies to regulate different industries will vary substantially.
The optimal selection of a regulatory strategy will also depend upon the program's
objectives. For example, if stimulating technology advancement is considered of most
importance, a marketable permit program with an ordinary auction might be most preferable.
Alternatively, if distributional considerations are considered more important, a permit program
with freely granted or zero-revenue auctioned permits, or perhaps a fee program with rebates,
might be most preferable. Similarly, marketable permit programs might be best if certainty of
emission reductions is of most importance (especially if product performance problems exist),
but might be the worst if protecting consumers from potential future product price increases is
of most importance. Tradeoffs are intrinsic to policy design, and the best regulatory strategy
will depend upon the particular universe of sources being regulated and the priority of
objectives.
7-8
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CHAPTER 8
AEROSOL PRODUCTS AND PACKAGING SYSTEMS
Aerosol consumer products have been the subject of much discussion since the mid-
1970' s. Because of the degree of confusion and misinformation surrounding these products and
their effect on the environment, the EPA included them as one of the major topics to be
addressed by the consumer and commercial products study. The purpose of the aerosol products
and packaging systems study is to develop information on these products and their delivery
systems in order to determine their environmental significance and communicate this information
to the Congress and the general public.
The term "aerosol product" is defined by the Chemical Specialties Manufacturers
Association (CSMA) as "a sealed container pressurized with liquified or compressed gases so
that the product is self-dispensing." The Department of Transportation (DOT) defines an aerosol
as "a sealed package containing base product ingredients, in which one or more propellants are
dissolved or dispersed, and fitted with a dispensing valve." According to these definitions,
products such as trigger sprays or pump action dispensers are not considered aerosol products.
The concept of the aerosol product as a system is emphasized throughout the report.
There are 4 primary components of the aerosol system: the product, the propellant, the valve,
and the container. The product and propellant collectively are referred to as the formulation.
Ideally, the system is designed such that each component operates in concert with the others.
Consequently, as in any system of interrelated components, modification of one or more system
components must be carried out judiciously in order to preserve the functionality of the system.
The individual components of the aerosol packaging system and their interactions are discussed
in detail in Section 8.2.
8.1 AEROSOL CONSUMER PRODUCTS AS SOURCES OF VOC EMISSIONS
In today's aerosol industry, nearly all aerosol consumer products employ hydrocarbon
(HC) propellants. These propellants (primarily propane, normal butane, and isobutane) are
VOC. The HC propellants were substituted for chlorofluorocarbons (CFC's) which were
determined to contribute to the depletion of stratospheric ozone. The conversion to HC
propellants was initiated by the industry in 1975 and was virtually complete by 1978, when the
EPA banned the use of CFC's in most aerosol products. A discussion of this shift in propellants
and its effect on the aerosol industry is presented in Section 8.3.
The CSMA publishes an annual Aerosol Pressurized Products Survey that reports
information on aerosol containers filled in the United States. The 1989 CSMA survey reports
that approximately 2.9 billion units were filled in the United States in 1989.1 Table 8-1 presents
data from the 1989 survey for several categories and subcategories of products. As the table
shows, personal care products comprise the largest category followed by household products,
automotive/industrial products, paints and finishes, insect sprays, and others, respectively. Hair
sprays alone account for almost 18 percent of the number of all aerosol products filled in the
United States. The next highest volume category includes paints, primers, and varnishes.
8-1
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8.2 AEROSOL SYSTEM COMPONENTS
The purpose of this section is to describe the components of the aerosol system, to
discuss the issues that are considered critical when designing a product, and to explain how these
issues can affect VOC emissions. There are 4 primary components that comprise the aerosol
system: the product, the propeUant, the valve, and the container. Each of these components
must be designed so that the product will meet the needs of the consumer. The formulation
(product and propellant) is the most important part in that it must perform as designed, while
being chemically compatible with the can and valve materials. The propellant must provide
enough pressure so that the entire contents of the can will be expelled, yet not so much pressure
that the product becomes dangerous or the spray pattern deteriorates. The valve design must
achieve the desired spray pattern and delivery rate. The container must be designed for safety,
cost effectiveness, and attractiveness.
8.2.1 Formulation
Almost all products that are available as aerosols are also available in other packaging
forms such as creams, gels, or liquids. A product is packaged as an aerosol because of benefits
to the consumer. To benefit the consumer, the product must be efficacious, that is, it must
perform the function for which it is designed. The product should be convenient, safe, and
aesthetically pleasing (i.e., it should have little or no offensive odor, not be messy, and be
attractively packaged). The success of the marketed product depends on how well the system
meets each of these criteria.
An aerosol formulation is made up of 3 major components: the active ingredients, the
solvent, and the propellant. The active ingredients are the materials essential for the specific
application for which the aerosol was designed. For example, the active ingredient in a paint
is the suspended solids, and the active ingredient in an insecticide is the toxin. Solvents are
usually present to act as diluents or to bring the active ingredients into solution with the
propellant. Typical solvents include ethanol, odorless mineral spirits, and in some cases, water.
The propeUant is the third part of an aerosol and is discussed in more detail in Section 8.2.2.
The active ingredients are designed for a specific purpose such as odorizing (perfumes
or deodorizers) or killing insects (insecticides). The chemicals that make up the active
ingredients are almost as diverse as the number of products that are available. Because of this
diversity, it is difficult to make generalizations about formulations. Any detailed discussion on
formulations must take into consideration specific applications.
While solvents perform a number of functions in aerosol products, their primary purpose
is to mix the active ingredients with the propellant. Solvents are also added to control the
particle size of the spray. For example, if the formulation consists of chemicals that rapidly
evaporate after discharge, a solvent may be added to retard the rate of evaporation, resulting in
8-2
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TABLE 8-1
U. S. AEROSOL PRODUCTS FILLED IN 1989 3
Major Category
Penonal Care Product*
Houaebold Product*
Automotive/Industrial
Paint* and Finiahei
Inaect Sprayi
Food Product*
Animal Product*
MUcellaneoui
TOTAL
Subcategory
Hair Spray*
Shaving Cream*
Antiponpinata/Daodocanti
Medicinala/Phartnar«i>aHrali
Other Hair Product*
Colofnea/Perftnne*
Subtotal
Room Deodoranta/Duwfectant*
Oeanen
Laundry Product*
Waxea/Poliahe*
Other Household Product*
Subtotal
Lubricant*
Refrigerant*
Carburetor/Choke Cleaner
Engine Starting Fluid
Tire Inflator/Sealant
Cleaners
Brake Cleaner
Engine Degreaier
Other Automotive/Induatrial
Spray Undercoating
Windahield/Lock De-icer
Subtotal
Paint*, Primera, Varnishes
Other Related Product*
Subtotal
Space Insecticides
Residual Inaecticidei and Repellent*
Subtotal
All Type*
Veterinarian and Pet Product*
Other Product*
Us** Filled
Number
316,193,000
232,476,000
221.7S1.000
30.MS.OOO
9356,000
3,050,000
1 .338.000
1,013,660,000
220,660,000
173,838,000
144,850,000
94,951,000
45.800.000
680,000,000
114,932,000
101,141,000
49,603,000
42,726,000
35,728,000
33,292,000
31,008,000
27,665,000
23,622,000
9,446,000
5.828.000
475,000,000
331,436,000
18.564000
350,000,000
124,538,000
72.462.000
197,000,000
175,000,000
8,000,000
12.000,000
2,910,660,000
Cattery (*)
50.9
22.9
21.8
3.0
0.9
0.3
_JL1
100.0
32.5
25.6
21.3
13.9
_L2
100.0
24.2
21.3
10.4
9.0
7.5
7.0
6.5
5.8
5.0
2.0
__L2
100.0
94.7
— L3
100.0
63.2
?$.?
100.0
100.0
100.0
100.0
Total
(*)
17.7
8.0
7.6
1.1
0.3
0.1
_JL2
34.9
7.6
6.0
5.0
3.3
_L«
23.4
3.9
3.5
1.7
1.5
1.2
1.1
1.1
1.0
0.8
0.3
_OJ
16.3
11.4
_M
12.0
4.3
-IS.
6.8
6.0
0.3
0.4
100.0
8-3
-------
a larger droplet size. In some cases, solvents are also added to reduce the vapor pressure of
the propellant system so that the aerosol product will comply with Department of
Transportation (DOT) regulations.
To successfully market a product, the manufacturer (marketer) must go through a
series of steps. First, the product must be developed. The active ingredients, inactive
ingredients, and the propellant system must be selected. The next step is to determine if the
formulation is compatible with the packaging system and if it is chemically stable. It is
important to ensure that the formulation will not corrode the can or dissolve the valve. It is
equally important that the formulation remain stable throughout the lifetime of the product.
Next, the marketer must test the product to ensure mat it is safe. This entails flammability
testing and lexicological studies. Once it is determined that the product is safe, the product
must be tested for performance in the field to ensure that the product performs as expected in
the hands of the consumer. The next step is consumer testing, in order to determine whether
the product is likely to be accepted by the consumer. The marketer is then ready to initiate
the purchase of equipment or the negotiation of contracts to produce the product, etc.
Concurrently with the last 3 phases, the marketer usually obtains the necessary
governmental approval. For example, insecticides, insect repellents, disinfectants,
disinfectant cleaners, fungicidal sprays, and herbicides are regulated by the EPA under the
Federal Insecticide and Fungicide and Rodenticide Act (FIFRA). The regulations require all
products subject to the Act to be registered with the EPA before interstate shipment can
occur. The regulations also contain labeling requirements for the products that are affected.
The Food and Drug Administration (FDA) regulates foods, drugs, cosmetics, and
medical devices. The FDA must approve all ingredients in food products. Food additives,
including propellants, must be on the FDA's "Generally Recognized as Sale" list. The FDA
must also approve all drugs. An extensive new drug approval (NDA) process is required of
each new pharmaceutical product. Although "over-the-counter" (OTC), drugs do not require
such pre-market approval, they must meet the criteria of an existing drug monograph. Any
drug product that deviates from an existing drug monograph is subject to the more extensive
NDA process. Personal care products that affect bodily functions (e.g., antiperspirants,
sunscreens, eye drops, etc.) are regulated by the FDA as drugs. Although the FDA does not
require pre-market approval of cosmetics, it has authority to regulate cosmetic products. It
can ban or restrict ingredients for safety reasons, mandate warning labels, inspect
manufacturing facilities, issue regulatory letters, seize illegal products, and engage in
nationwide recalls.
In general, it takes 2 to 5 years to get an aerosol product to the market. This time
frame depends on the degree of product development, the extent of the required testing,
regulatory requirements, and production needs.
8.2.2 Propellant
An aerosol propellant is defined as "a fluid capable of exerting a pressure when held
in a sealed container at room temperature. "^ There are 3 major classes of propellants:
fluorocarbons, hydrocarbons (HC's), and compressed gases. The fluorocarbons can be
8-4
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further divided into chlorofluorocarbons (CFC's), hydrochlorofluorocarbons (HCFC's), and
hydrofluorocarbons (HFC's). The VOC include HC's (propane, normal butane, and
isobutane) and dimethyl ether. The non-VOC compressed gases that are typically used as
aerosol propellants are carbon dioxide (CQ2), nitrous oxide (N2O), nitrogen (Njj), and
compressed air.
The first significant aerosol product was an insecticide produced in 1943 for use by
U.S. combat troops. This product and subsequent aerosol products used CFC's as
propellants primarily because they are nontoxic and nonflammable. The HC propellants did
not enter the market until about 1954. Studies conducted in the 1970's implicated the CFC
propellants as contributing to the depletion of stratospheric ozone. Therefore, in 1975, the
aerosol industry began substituting HC's and compressed gases in those aerosol products
being manufactured that used CFC's. In 1975, approximately 50 percent of all aerosols were
filled with HC propellants. This conversion was costly to the aerosol industry because many
existing plants were not designed to handle flammable propellants. By 1978, when CFC's
were banned by the EPA for use in most aerosol products, the conversion from CFC's to
HC's was virtually complete.
A propellant functions by exerting pressure inside the container and forcing the
product through the dip tube and into the rest of the valve assembly. When the valve is
opened, the product is forced out of the container by this pressure. Liquified gas propellants
(e.g., fluorocarbons or HC's) are used because they will maintain a relatively
constant pressure as the contents of the can are expended. A constant pressure is maintained
because the liquid propellant is constantly vaporizing into the head space of the container.
As the liquid level of the container drops, more liquid-phase propellant vaporizes until
equilibrium is established. The liquid serves as a reservoir to maintain the total pressure as
the product level drops. This mechanism is contrasted with the compressed gases that lose
pressure as the head space inside the container increases. Consequently, when a compressed
gas is used, the container must be initially "over-charged" so that there will be sufficient
pressure to expel the entire contents.
The physical properties that affect how a propellant functions in a specific application
are the propellant's vapor pressure, solubility, and viscosity. The vapor pressure determines
how much pressure is exerted on the liquid inside the container which, in turn, will affect the
spray characteristics of the product. The solubility affects the manner in which the product
must be used by the consumer. If the propellant is not soluble in the formulation, it is a
two-phase formulation, and the container must be shaken in order to mix the propellant and
product. If the propellant is soluble in the product, then it is a single-phase formulation, and
no agitation is necessary. This is important because some products, such as wall dispenser
air fresheners, cannot be shaken. Therefore, they must be single-phase formulations. The
solvent properties of the propellant in relation to the valve components, such as gaskets and
dip tubes, can also be important. If the propellant dissolves the valve components, the con-
tainer may leak or the valve may not function correctly. Furthermore, the propellants must
be pure. Impurities can result in problems such as inoperable valves or container corrosion.
The propellant must be chemically stable in the formulation so that the propellant and
product or solvent do not react to form undesirable compounds. The spray characteristics
are affected by the viscosity. A high viscosity formulation may be discharged as a stream
8-5
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and not a spray. The propellant also influences whether the product is discharged as a foam,
stream, or spray.
In addition to the propellant's physical properties, die formulator must consider its
flammability, toxicity, odor, and cost. If the propellant is flammable, precautions must be
taken during storage and the filling process to minimize the possibility of explosion. If the
propellant is toxic, specific procedures must be implemented to protect employees, and the
propellant is unsuitable for some applications such as food or personal care products. If the
propellant has an undesirable odor, the consumer is less likely to use the product. If the
propellant is very expensive, the cost of the product may affect consumer acceptance. When
selecting a propellant for a product, the marketer must be aware of the ramifications of each
of these issues.
Propane, n-butane, and isobutane are the principal VOC propellants used in today's
aerosols. An additional VOC propellant, dimethyl ether (DME), is gaining more acceptance
in the aerosol consumer product market.
The HC propellants are used because they have several very attractive properties.
They are nontoxic, noncarcinogenic, noncorrosive, abundant, and cost effective (currently
$.19 per pound, plus freight). These liquified gas propellants provide a consistent pressure
over the life of the product, and they can be blended to achieve a wide range of vapor
pressures. They are easy to transport, store, and handle. The major disadvantages are that
they are flammable and that they are photochemically reactive in the atmosphere (i.e, they
contribute to the formation of tropospheric ozone).
To achieve desirable spray characteristics, the formulator may require a propellant
that has a pressure different from the vapor pressures of any of the pure compounds. This
can be achieved by blending two propellants. The most common mixture is a
propane/isobutane blend. For example, a mixture of 41.9 percent (by weight) propane and
58.1 percent isobutane results in a propellant with a pressure of 70 psig at 70°F. A
significant problem associated with a HC blend is that the more volatile component of the
mixture vaporizes into the headspace more quickly than the lower volatility component. As
the product is expelled (and the higher volatility component is expended more rapidly than
the lower volatility component), the lower volatility component accounts for an increasing
percentage of the liquid propellant mixture. Consequently, the total pressure of the mixture
decreases with product usage. This problem is exacerbated with the use of vapor tap valves
because the higher volatility component is lost not only to the headspace but through the
valve as well.
Compressed gases (e.g., CO2, N2
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product formulation and generally functions both as a propellant and a solvent.
Consequently, removal of the HC propellant must be accompanied by addition of a solvent.
Compressed gases are high-pressure propellants that must be injected into the aerosol
container in gaseous form instead of as a liquid under pressure. A compressed gas differs
from a liquid HC propellant in that the vapor pressure of the HC propellant remains constant
(at a given temperature) as long as there is liquid propellant in the container. When a com-
pressed gas is used, the can pressure decreases as the contents of the can are expelled. As
the volume of head space in the can becomes larger, the pressure decreases. Since the
pressure decreases as the product is used, the filler must "over-charge" the can to ensure that
the system will provide sufficient pressure to expel the entire contents.
Fluorocarbons, specifically CFC's, have been used as aerosol propellants for many
years. These chemicals are nontoxic and nonflammable, which makes them attractive for use
in aerosol consumer products. However, the use of these compounds in most aerosol
propellant applications was banned in the United States in 1978 because of their potential to
deplete the stratospheric ozone layer. The "Montreal Protocol on Substances that Deplete the
Ozone Layer," a protocol to the "Vienna Convention for the Protection of the Ozone Layer,"
has been ratified by 65 countries and calls for a reduction in the production and consumption
of CFC's. The Clean Air Act Amendments of 1990 require a phaseout of most CFC
production by the year 2000.
8.2.3 Valve Assembly
This section describes the various valve components and the general types of valves.
Most aerosol valve assemblies consist of 7 components: actuator, mounting cup, stem, stem
gasket, spring, body (or housing), and dip tube. Figures 2-2 and 2-3 are diagrams of a
vertical action valve. In general, the valve opens when a downward force is applied to the
actuator, and it closes when the force is released. There are several different kinds of
valves: vertical valves, tilt valves, female valves, "total release" valve systems and other
special application valves. Valves must be designed to perform specific functions. Many
aerosol products must deliver a fine spray. For these products the valve must be designed to
break the liquid up into small particles. Products that are to be sprayed on a surface,
whether it be a hard surface (paint) or the body (underarm deodorant), must have a valve that
optimizes transfer efficiency. Some other types of valves include metering valves (dose
inhalants), inverted use valves (compressed gases) and total release valve systems (indoor
foggers), female valves (paints), and tilt valves (starches). In addition to the different valve
types, there are over 300 varieties of valve bodies, a wide variety of stem gasket materials, 6
different sizes of valve springs, 5 variations of dip tubes, 2 materials for valve cups, and
several types of valve gaskets. Each combination is designed to fulfill a set of specific
functions.
Many different variables must be considered when deciding which valve is best suited
for a specific application. The formulation must be tested to determine if it is compatible
with the stem gasket, dip tube, valve body, and mounting cup. The manufacturer must also
know what specific spray characteristics are desired so that a choice of mechanical breakup
system, orifice size, and dip tube diameter can be made. If the product is prone to clogging,
8-7
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a female valve may be the best choice for the product. There are hundreds of different
permutations of valve components, and the marketer and manufacturer must select a
combination that will ensure that the specific product performs optimally.
8.2.4 Containers
The container is a critical component of an aerosol consumer product because it must
withstand the pressure of the product formulation and propellant without bursting or leaking.
It is also the portion of the product that the consumer sees when making a decision to buy a
particular product. Therefore, it must be attractive and cost effective. Aerosol product
marketers must consider each of these aspects of can design in order to choose a can that will
be best suited to a specific application.
The DOT is responsible for regulating the transportation of hazardous materials.
Almost all aerosol products are classified as materials presenting a limited hazard during
transport due to their form, quantity, or packaging. The Code of Federal Regulations, Title
49, Part 173.306 (49 CFR Part 173.306) governs the shipment of most aerosol products.
These regulations dictate the type of packaging that can be used (transported) based on the
pressure of the product.
8.3 INDUSTRY PROFILE
8.3.1 History and Development
Aerosol products existed as early as the 1860's, with the first known aerosols being
milk products and other beverages which were dispensed in aerated form through the use of
carbon dioxide as a propellant. About 1910, cans and glass tubes of ethyl chloride were sold
as topical anesthetics that chilled the skin prior to minor surgery. The most significant early
work in aerosol product development was done in 1922, when Eric Rotheim of Norway
developed an aerosol package comprised of a heavy brass shell and a primitive, threaded
valve. Propellants for these early systems included isobutane, vinyl chloride, carbon
dioxide, methyl chloride, and dimethyl ether. No further development of the aerosol
packaging concept occurred until 1943, when U.S. Department of Agriculture researchers
(Lyle Goodhue and William Sullivan) developed an insecticide "bomb" for use by U. S.
troops in the South Pacific islands. Over 30 million of these units were produced from 1943
to 1947. These products utilized CFC propellants which were developed during the 1930' s
by Thomas Midgley of DuPont. Hydrocarbon propellants came into limited use in 19S4,
when Phillips Chemical Company introduced essentially odorless "Pure Grade" propane and
butanes, and Risdon Manufacturing Company developed the first reliable mechanical breakup
valve.2
A significant activity of today's aerosol industry is consumer education. Many
consumers continue to believe that most aerosol products are propelled by CFC's and,
therefore, contribute to stratospheric ozone depletion. One industry organization, the
Consumer Aerosol Products Council (CAPCO), has produced an educational video, "The
Aerosol Adventure - How Tech Makes It Tick," that explains aerosol technology to a target
audience of sixth to ninth grade students.*
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8.3.2 Structure of the Aerosol Industry
Aerosol fillers perform the task of injecting the product formulation (product and
propellant) into the aerosol container and sealing the pressurized container. Aerosol
containers are either filled in-house by the marketer of the product (captive filling), or the
filling operation is contracted out to another company (contract filling). There are
approximately 100 fillers in the United States. About half these fillers are contract fillers
that fill exclusively for the trade, while the other half fill for themselves as well as for
marketers. The product formulation is usually blended at the same facility as the filling.
Therefore, most fillers are also formulation blenders.
Because some companies fill exclusively for the trade and others fill for themselves as
well as for other companies, it is hard to define a clear relationship between the fillers and
other members of the aerosol industry. It is known, however, mat many contract fillers form
one-on-one relationships with formulators and marketers. These relationships create a
dependence on the formulator and marketer for business.
Aerosol formulations for individual products are specified by the marketer.
Generally, the formulation is blended at the same facility where the can is filled (either a
captive or contract filler). In a few cases, usually involving proprietary, formulations, the
formulation is blended at a separate facility and is shipped to the filler.
Propellant suppliers are another segment of the industry. Currently, about 81 percent
of U. S. aerosol products are pressurized with HC propellants. Another 7 percent use CQ2,
and the remaining 12 percent use N2O, CFC's, DME, N2, HFC-152a, and HCFC's (listed
in approximately descending order).
Seven companies in the United States supply aerosol-grade HC's. Currently, 3
companies (Aeropres Corporation, Diversified CPC International, and Phillips 66 Company)
produce over 80 percent of the HC propellants used in the United States. For some of these
companies, the production of aerosol propellants comprises virtually 100 percent of their
business (i.e., aerosol products are the only use for the propellants they manufacture). For
example, Aeropres Corporation is almost totally dependent on the aerosol industry, because
their primary activity is the production of aerosol propellants. Although they market small
quantities of highly purified gases for instrument calibration purposes and some unpurified
fuel gases, these markets represent only a small fraction of Aeropres's overall business. For
more diversified companies such as Phillips 66 Company, the production of aerosol
propellants may represent a much smaller segment of their overall business.
Approximately 25 container manufacturers supply tinplate, aluminum, glass, and
plastic cans for the aerosol industry. Although many of these companies also produce
nonaerosol containers or other products, some depend on the aerosol industry for most of
their business. When malting a decision about what type of can to use for a specific product,
the marketer must consider the size of the can, whether the formulation may react with the
can, what the pressure rating of the can should be, the aesthetics of the can, and product
safety.
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The valve is an essential element of every aerosol dispenser. When actuated, it
releases the product from the container and produces a spray pattern appropriate for the
specific application. In the United States, 9 firms supply virtually all aerosol valves. Three
companies (Precision Valve Corporation, Seaquist Valve Company, and Summit Packaging
Systems) supply over 90 percent of the aerosol valves used in the United States. Each of
these companies, while also involved to varying degrees in the production of pump spray
valves, depends on the production of aerosol valves for pressurized containers as a major
portion of their business.
Although some valve manufacturers list suggested specific valve combinations for
various standard aerosol products, the companies usually manufacture valves to the
marketers' specifications. One U. S. valve manufacturer reportedly has over 10,000 specific
aerosol valve designs from which to choose. While many marketers have their own unique
ideas concerning what constitutes an acceptable spray pattern, a large degree of supplier
Intel-changeability can be obtained by maintaining the same orifices, gaskets,
and other attributes during the development of alternative or secondary source valve
specifications.
Aerosol cover caps are necessary to protect the spray head from damage, prevent the
actuator from discharging the contents during storage, prevent accumulation of dust or dirt
on the valve, and enhance the general appearance of the container. Two companies (Berry
Plastics and Knight Plastics) produce over 90 percent of the aerosol caps used in the United
States.
8.4 ALTERNATIVE DISPENSING TECHNOLOGIES
One option that has been suggested as a means of reducing VOC emissions from
aerosol consumer products is to switch from conventional aerosol packaging systems to
alternative technologies that reduce the amount of HC propellant required to expel the
product. While this is a reasonable and effective approach for many applications, each
individual conversion must be considered carefully with regard to the net: environmental
benefit that will be achieved. This section describes the advantages and limitations of several
alternative packaging technologies that have been or may be used for consumer products.
8.4.1 Bag-in-Can System
One alternative dispensing system for aerosol products is the bag-in-can system. This
container (aluminum or tinplate) houses an inner bag containing the product concentrate and
the exo-space propellant. The bag can be made of one of several different materials to
ensure that the product and the propellant are kept separate. Under normal use, the system
is designed to permit gas-free dispensing; however, upon disposal, the propellant would
likely be released to the environment. The top of the can is fitted with a valve and an
actuator. As the actuator is depressed, the inner bag begins to collapse due to the pressure
of the exo-space propellant, and the product is dispensed. The Sepro Can was the first bag-
in-can unit introduced for aerosol products.
8-10
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There are limitations to this type of packaging system, some of which are listed
below:
• Products with high viscosities - result in slow transport through valve
• Products that are highly lubricating - result in a loss of seal for rubber
components
• Products that are acidic - tend to attack certain types of bag materials
• Products with long shelf lives before use - the propellant permeates the bag
and enters the product
• Products containing strong solvents - result in bag degradation or dissolution
• Products that must be hot-filled - results in flammability hazard and/or bag
distortion
Most bag-in-can systems use HC propellents such as n-butane, isobutane, propane,
and their blends. The use of compressed gases is severely limited because there is no
reserve against slow leakage, and the propellant may be unable to dispense the entire
contents of the can.
8.4.2 Piston Cans
A second type of alternative aerosol dispensing system is the piston can. This unit
consists of an aluminum or tinplate can and a free-floating polyethylene piston that separates
the propellant from the formulation. The propellant is injected through the base of the can
below the piston. Hydrocarbons are the most common propellant type for the piston cans.
Compressed gases cannot be used because they do not maintain a constant pressure as the
contents are expelled.
These systems can be used for creams, gels, pastes, lotions, and other low to medium
viscosity products such as shave creams, chocolate syrups, margarine, air fresheners,
cheeses, cake toppings, and silicone-based tub and tile sealants. Piston cans typically
dispense 95 to 98 percent of their contents. Limitations of piston cans include:
• Products with low viscosity will distort the piston
• Piston bypass and permeation will result in propellant reduction and foam
generation in the product
• Incompatibility of the product with the can or piston
Piston cans are similar to the bag-in-can systems in that only a small amount of
propellant is needed to dispense the contents. Typically, the piston can requires about
O.S percent propellant. This can be compared to 3 percent used with traditional viscous
aerosol products.
8.4.3 Enviro-Spray* System
The Enviro-Spray* system is the opposite of the bag-in-can system in that the product
occupies the exo-space, and the propellant is inside the bag. The propellant bag consists of a
large pouch containing a 50-percent citric acid solution in water, and four smaller pouches
8-11
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containing sodium bicarbonate. The smaller pouches are ruptured as the contents are
expelled and the bag expands, pressurizing the container. Mixing of the citric acid and
sodium bicarbonate produces sodium citrate salts and CO2 gas that maintains the pressure in
the unit at the original level. The product can be dispensed as a coarse spray, gel, paste, or
post-foaming gel. The citric acid pouches in this unit are laminates that have a core layer of
aluminum or polyester. The reservoir of sodium bicarbonate for die first pressurization step
is contained in a special water-soluble polyvinyl alcohol bag. This system does not require
any VOC propellants.
Enviro-Spray* dispensers are used for various insecticides, leaf shines, shave creams,
colognes, nibefacient creams, catsup, mustard, and plant nutrient sprays. Some limitations
of this dispensing system include:
• Product incompatibility with the can
• Product incompatibility/permeation of the pouch
• Variations in delivery rate due to pressure fluctuations
8.4.4 Pump Sprays
There are two basic types of pump dispensers, the aspirator type and the standard
mechanical type. The aspirator type consists of a jar containing a dip tube, which aspirates
the product into an orifice and out of the dispenser as a spray. Aspirator pumps have been
used primarily for space spray insecticides; however, smaller versions of this type have been
used for perfumes and colognes. The primary limitation of these units is that the product
must have low viscosity so that it can be dispensed as a spray.
The aspirator-type pump sprayer consists of a cylinder and piston arrangement connected
to a reservoir from which the product is aspirated through the dip tube, through a jet orifice,
and propelled by a stream of air. An example of this type dispenser is the old "FLIT" gun.
These have been used mainly for insecticides and were sold by companies such as Exxon and
Gulf. Today, only a very limited number of these units are sold. These units do not use any
kind of propellant.
The standard-type pump sprayers commonly in use today exist in two forms, the finger-
pump sprayer and the trigger-action sprayer. The operating principles of the two systems are
the same. The actuator/valve assembly usually has a threaded connection that fits into a
glass or plastic container. As the actuator is depressed, the valve stem is forced downward
into the body chamber that is normally filled with product. The product forces the chamber
to expand outward, allowing product to flow past the piston into the orifices of the stem.
The liquid then moves up the stem, through the adapter and button, and out the actuator as a
stream or spray. When the button is released a partial vacuum is created in the chamber
allowing product to refill the body chamber! The principal differences between the finger-
and trigger-pump sprayers are the amount of product dispensed per actuation and the
mechanical advantage of the pinioned trigger that provides higher internal pressure in the
chamber.
8-12
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8.4.5 Dispensing Cjpsures (Squeeze Bottles)
Another aerosol alternative is the screw-threaded closure or cap with a dispensing hole
which is plugged shut by various cap features when the product is not in use. A metal can
or flexible plastic container is inverted and squeezed to dispense the product. This type
dispenser is very efficient, because only the amount of product that adheres to the inside
walls of the container will not be dispensed. These units are used for liquids, thin gels, soft
creams, and lotions. Some examples are charcoal lighters, cosmetics, toiletries, other
personal care products, paint thinners and strippers, furniture polishes, margarine, catsup,
mustard, lubricants, carburetor and choke cleaners, silicone shoe and boot dressings, etc.
The primary limitation is that the product dispensed in these units must be able to flow
freely. Consequently, many of these products may require addition of solvent in order to
achieve acceptable performance.
8.4.6 Twist-N-Misr»
The Twist-N-Mist n* is a pressurized packaging system that dispenses the product using
energy supplied by manually rotating the full-diameter screw cap and integral piston. This is
a propellantless dispenser. Accordingly, the only VOC will be those associated with the
product itself. By twisting the threaded cap several revolutions, the piston is raised, creating
a vacuum in the reservoir below. This causes the product to rise through the dip tube, past
the stainless steel ball check valve, and into the cavity. The cap is then twisted an equal
number of turns in the opposite direction, moving the piston downward, pressurizing the
reservoir, and forcing the product into a Buna-N rubber bladder. The "memory" of the
elastomer causes the bladder to return to its original shape as the product is dispensed
through an aerosol-type valve. This unit dispenses about 95 percent of the product.
Currently existing drawbacks and limitations of this system include:
Persistent stress cracking problem
Inconvenience in that it can require many turns to expel the product
Products cannot include foams
Products cannot contain solvents incompatible with the Buna-N bladder
Product incompatibility with the bladder results in product discoloration or odors.
8.4.7 The Exxel* System
Another alternative dispenser is the Exxel* system by Exxel Company, which consists of
a thick, elastomeric rubber sleeve whose open end is fitted with a valve and actuator. The
product is compressed into an inner PET sleeve and, because of the elasticity of the outer
sleeve, is under pressure. Products currently dispensed in the Exxel* uni^ include welding
flux spray, sun oil spray, muscle relaxant, sterile food products, Betadine topical antiseptic
solution, fragrances, hair gel, shampoo and conditioner, and hand and body cream. Skin
care, hair care, and pharmaceutical products of the post-foaming gel type are in the
developmental stages. The limitations of the Exxel system include the following product
types and/or conditions:
8-13
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Solvents such as terpenes and ketones
Products with pH values over 10.0
Products containing more than 5 percent isopropanol
Products containing more man 60 percent ethanol
Prolonged exposures to temperatures over 113°F
High surface tension products
Resins capable of drying and clogging actuators
Products that require in-package mixing
8.4.8 The Mistlon Eco-Logjcaj* System
The Mistlon Eco-Logical* Spray Bottle is a propellantless system in which the product is
poured into a bottle fitted with a screw-threaded closure with an aerosol valve and actuator
and a polypropylene cap. The base section of the unit contains a hollow cylinder with a one-
way compound valve, which functions as a piston within a cylinder protruding into the
container, also ending in a one-way valve. To pressurize the air in the container, the base
section is pumped a number of times. The maximum pressure achieved is about 100 psig.
By pressing a soft diaphragm in the center of the base, excess air pressure within the hollow
cylinder is removed. The spray is very coarse. However, the unit can be equipped with a
MBU unit to produce a more acceptable spray.
8.4.9 Airspray* System
This propellantless system is similar to the Mistlon Eco-Logical* system in that it uses a
pumping action to compress air into a pressure-resistant container. This unit is distributed
with a refillable screw top or with a disposable crimp-on. The containers can be made of
plastic, metal, or glass. When pressurized to the maximum pressure of 55 psig, this unit
will dispense up to 100 ml of product before it requires repumping.
The limitations of the Airspray* system are similar to those of the Mistlon Eco-Logical
system. It is not compatible with highly flammable formulations and formulations that deform
polypropylene or attack polyvinyl acetate. It should not be used for products that are highly
viscous or are direct foams.
8.4.10 The Selvac* System
The Selvac* system is a self-pressurized dispensing system. It consists of an aerosol
valve, an inner membrane made of butyl rubber to hold the product, and an outer energy
storage structure. The outer structure expands when the unit is filled under pressure with the
product. When the actuator is depressed, the outer energy structure exerts pressure on the
inner membrane and causes the product to be dispensed through the actuator. This system
can be used for liquids, pastes, gels, lotions, and creams. Typical products include bath
gels, body lotions, deodorants, hair products, shampoo, toothpastes, air fresheners,
disinfectants, insect sprays, plant sprays, stain removers, antiseptic sprays, nasal sprays,
dental products, topical creams, and flea and tick sprays.
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8.4.11 The Wording Nature Spray* System
The Werding system consists of various actuators and nozzles, depending on the product
to be dispensed. The Werding 'R' Actuator can be designed to provide a constant delivery
rate, regardless of the internal pressure of the unit, thereby making it most useful for
products pressurized with compressed gases. The thrust regulator controls flow into the
nozzle, where the multistaged, interconnected venturi system results in a higher mechanical
breakup effect than conventional actuators. The system also includes two stainless steel
accelerator discs, a plastic expansion chamber, and a regulation disc. The design of the
regulation disc and the nozzle are responsible for the regulation of the product flow. Under
high pressures, the metal disc compresses, and the orifice size increases. This causes an
increase in turbulence and a resistance to product flow through the thrust regulator. This
ability to accommodate pressure fluctuations results in a constant dispensing rate of the
product.
8.4.12 Vaporizers
Vaporizers provide mists or condensation nuclei of the product in the air. Electrically
operated vaporizers consist of a wafer containing the concentrate and a small heater that is
connected to an electrical wall outlet. As the wafer is warmed, the product is vaporized and
released into the air. These units are used primarily for insecticides and air fresheners and
are limited to products with appreciable vapor pressures.
8.5 REFERENCES
1. Chemical Specialties Manufacturers Association, Aerosol Pressurized Products Survey -
United States 1989, published 1990.
2. Johnsen, M., The Aerosol Handbook, 2nd Edition, The Wayne Dorland Company,
Mendham, New Jersey, 1982.
3. Meeting of National Aerosol Association and U.S. EPA, Office of Air Quality Planning
and Standards. Durham, North Carolina. May 7, 1991.
4. Telephone conversation between B. Moore, U.S. EPA, and D. Minogue, Precision Valve
Corporation, October 23, 1991.
5. Meeting Summary, Chemical Specialties Manufacturers Association (CSMA) and
National Aerosol Association (NAA) Participation in EPA Study on Volatile Organic
Compounds (VOC) in Consumer Aerosol Products. U. S. Environmental Protection
Agency, Research Triangle Park, NC. July 2, 1990.
8-15
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TECHNICAL REPORT DATA
(Please read Instruction* on the reverse before completing/
i. REPORT NO.
EPA-453/R-94-066A
RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Report to Congress on Volatile Organic Compound
Emissions from Consumer and Commercial Products
5. REPORT DATE
March 1995
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Bruce Moore
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Standards Division
Research Triangle Park, North Carolina 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
None
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This Report to Congress presents the findings of the EPA's study of consumer and
commercial products and addresses such topics as (1) scope of products covered by
Section 183(e); (2) emission estimates for all categories of products subject to
Section 183(e); (3) the role of consumer and commercial products in the ozone
nonattainment problem; (4) control measures and systems of regulation available under
Section 183(e); (5) the regulatory environment surrounding consumer products; and
(6) opportunities for emission reductions from regulation of specific categories of
consumer products. The Report also addresses the issue of relative photochemical
reactivity as it relates to consumer and commercial products, including: (1) a
description of the reactivity-related requirements of Section 183(e); (2) a discussion
of the science of photochemical reactivity; (3) an explanation of the role of relative
reactivity in developing ideal ozone control strategies; and (4) methodologies which
could be used now, based on the current uncertainties and limitations associated with
reactivity, to fulfill the requirements of Section 183(e). In addition, the Report
presents a detailed discussion of the criteria developed by the EPA for regulating
consumer and commercial products under Section 183(e), describes how the criteria are
being used, and lists the considerations on which the EPA will base the selection of
categories for regulation.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Air Pollution
Volatile Organic Compounds
Tropospheric Ozone
Consumer Products
Commercial Products
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Tins Report/
Unclassified
21. NO. OF PAGES
172
20. SECURITY CLASS .Tins pjgei
Unclassified
22 PRICE
EPA Form 2220-1 (Rev. «-77) PREVIOUS EDITION is OBSOLETE
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