PNEAC Fact Sheet
Determining VOC/HAP Emissions From Nonheatset Web Offset Lithographic Printing Operations
by Gary A. Jones

Background

The two most important aspects involved in air pollution control regulations for the printer is knowing how much air pollution is being released from their operation and what specific air pollution permit and possible control regulations need to be met. The first step in determining what permit or possible control requirements apply is to determine both the actual and potential emissions of air pollutants from each press and from the entire facility as some state/local permitting authorities require permits for individual presses and many operating permits are required for the entire facility.

The two principal pollutants of concern are volatile organic compounds (VOC) and hazardous air pollutants (HAPs). VOCs are those chemicals that will readily evaporate and lead to the formation of ozone in the lower atmosphere. There is a small list of chemicals that are considered exempt from the definition of VOC and the ones possibly found in offset printing include acetone, methyl acetate, and methylene chloride. (For more information see the PNEAC fact sheet "What are VOCs and Do Printing Materials Contain Them?" There is a list of 188 Hazardous Air Pollutants that are subject to regulation. A list of common HAPs found in offset lithographic printing operations is included in this fact sheet.

The principal reason why a printer needs to know their VOC and HAP emissions is because of construction and/or operating permits and emission inventory reporting requirements. Many state and local air pollution control agencies have instituted a system of permitting that requires a source of air pollution to obtain either a permit to construct and/or operate. Permits can be viewed as a contract between the printer and the permitting authority allowing the printer to operate as long as specified emission limits are not exceeded. If permits are required, they are required to be in hand prior to accepting delivery of a new press, significantly modifying an existing press such as adding a coating unit, or actually running the press.

The need to obtain an air pollution control permit depends on the threshold that has been set by the state and/or local air pollution control agency responsible for your area. The thresholds can be based on several different parameters. Some state and local agencies use an actual emission rate or amount emitted while others use a potential emission rate or amount threshold. Some agencies use actual material consumption rates to determine if permits are required. Permits can be required for a single piece of equipment or for an entire facility. The permitting thresholds can vary quite dramatically and it is important to know what the permit threshold is for your particular location. Even if a printer is not required to obtain an air pollution control permit, good environmental management practice dictates that emission calculations should be performed at lease annually or when significant changes occur. Examples of significant changes are when a new piece of equipment that emits air pollution such as a press is purchased or when an existing piece of equipment emitting air pollution is modified, such as adding a coating unit on a press. In order to verify that a permit is not required, some state and local air permitting authorities require printers to calculate the emissions. For more information see PNEAC fact sheet "Understanding Air Pollution Permits".

VOC and HAP Emissions From Nonheatset Web Offset Lithography

The majority of VOCs and HAPs emitted from the nonheatset web process are emitted through general pressroom ventilation air rather than through process stacks or vents. As a result of the lack of a definitive point of emissions from the nonheatset web press, the direct measurement of emissions (or emission rates) is difficult, if not impractical. Therefore, emissions have to be calculated from material use and material content information. This approach is quite acceptable to permitting authorities. In fact, this same approach is used for printing and coating operations (e.g., flexographic printing or rotogravure printing) where most or all of the VOCs and HAPs are emitted through process stacks or vents. The materials utilized in the nonheatset web offset lithographic printing process that contain VOCs and HAPs are the fountain solution with isopropyl alcohol or isopropyl alcohol substitutes/extenders, cleaning solvents used to clean ink and other press components, ink oils, coatings, and adhesives.

Other sources of emissions in a nonheatset web offset lithographic printing operation include parts washers, binding and finishing equipment, and some prepress equipment. While these sources are generally not significant, their emissions need to be included in a total facility emission inventory. In some instances, such as an ink jetting operation using solvent-based inks, some of the sources, other than presses, of VOC/HAP emissions may have to be permitted as the emissions could exceed the specified threshold.

VOC and HAP emissions from materials used in nonheatset web printing operations are a function of consumption multiplied by the VOC or HAP content and any applicable release factor. There are two extremely important retention factors that should be used in determining emissions from input materials. These retention factors allow for a reduction in VOC or HAP emissions because it has been established with USEPA that due to their physical characteristics and how certain materials are used and handled, they are not released into the air. In using the retention factors, it is important to check with the state/local air permitting authority to make sure their use is acceptable.

For determining VOC emissions from nonheatset web inks printed on paper, a retention factor of 95% has been accepted by USEPA. The 95% retention factor equates into a 5% release factor and was established as a result of ink oil retention studies conducted by the printing industry). The 95% retention factor was included in a document entitled Control Techniques Guideline for Offset Lithography, the PrintSTEP workbooks, the Potential to Emit (PTE) Guidance for Specific Source Categories memo and attached technical support document, and the Emission Inventory Improvement Program (EIIP) documents. The links to these references are provided at the end of this fact sheet. This retention factor is also to be used for any varnishes that would be applied as an overprint coating as they are essentially printing inks without pigments.

The other important retention factor for determining VOC and HAP emissions is the one for low vapor pressure cleaning solutions used in conjunction with shop towels. USEPA has established a 50% shop towel retention factor for cleaning solutions with VOC composite vapor pressures less than 10 mm Hg at 20oC (68oF). The shop towels need to be kept in a closed container when not being used. This retention factor was included in the Alternative Control Techniques Guideline for Offset Lithography, the PrintSTEP workbooks, the Potential to Emit (PTE) Guidance for Specific Source Categories memo and attached technical support document, and the Emission Inventory Improvement Program (EIIP) documents. The links to these references are provided at the end of this fact sheet.. The ACT guideline was released to supplement the draft Control Techniques Guideline (CTG) and provides significant revisions to some of the elements contained in the CTG.

No retention or release factors have been established for VOCs or HAPs used in fountain solutions, coatings, adhesives, or other materials used in nonheatset web lithographic printing operations. Therefore, all of the VOCs and HAPs in these materials would all be considered or assumed to be released into the atmosphere. The emissions from automatic blanket washers would all be considered released into the atmosphere. The only "credit" for VOC or HAP not released to the air would be for that contained in discarded wastes.

VOC Emission Calculation Worksheet For Nonheatset Web Offset Lithographic Printing

The following worksheet presents both the formulas and assumptions that can be used to determine both actual and potential VOC emissions from nonheatset web offset lithographic printing operations. The assumptions on retention and release factors are taken directly from the EPA documents described earlier.

Material Usage1 Units VOC Content2 Units Release Factor3 VOC Emissions4
Ink Pounds/Yr % by Weight
Fountain Solution (FS) Concentrate Gallons/Yr Lbs VOC/Gal
FS Additive Gallons/Yr Lbs VOC/Gal
Cleaning Solution Gallons/Yr Lbs VOC/Gal
Gallons/Yr Lbs VOC/Gal
Gallons/Yr Lbs VOC/Gal
Coatings and Conventional Varnishes Pounds/Yr % by Weight
Misc. Gallons/Yr Lbs VOC/Gal
Total VOC Emissions Gallons/Yr Lbs VOC/Gal

  1. Usage is defined as purchase amount minus change in standing inventory, minus the amount that is discarded.

  2. List either percent VOC content (by weight) or pounds of VOC per gallon for the product.

    1. The VOC content information may be provided by the supplier via the MSDS, USEPA Method 24 analysis (http://www.epa.gov/ttn/emc/promgate/m-24.pdf), or summing % content of all VOCs and multiplying it by the density to calculate VOC. If density is unknown, multiply specific gravity from MSDS by 8.33 lbs/gal.

    2. Do not include exempt VOCs such as Methylene Chloride, 1,1,1-Trichloroethane, Acetone, T-Butyl Acetate or Methyl Acetate. These exempt VOCs and their concentration should be identified in the Hazardous Ingredients section of the MSDS.

    3. For Ink VOC content, the amount can be determined by using the VOC content for each ink used or use the highest VOC containing ink in each category (e.g., black, blue, red, or yellow process inks and PMS inks).

  3. Use the following for the appropriate VOC release factor:

    Ink 0.05
    Fountain Solution Concentrate 1
    Fountain Solution Additive 1
    Cleaning Solution* 0.5
    Coating 1
    UV 1
    Water-based 1
    Conventional 0.05


    * The VOC composite vapor pressure of the cleaning solution cannot exceed 10 mm Hg at 20°C (68°F). Alternatively, the VOC content of the cleaning solution cannot exceed 30% by weight.

  4. The actual VOC emissions are determined by multiplying the Usage, VOC Content, and Release Factors together. The total VOC emissions are the result of adding all of the individual VOC emission determinations together. To convert the total pounds per year into tons per year, divide the total pounds by 2,000 because there are 2,000 pounds in one ton.

Annual Potential Emissions (APE)

Unfortunately, there is no one universal formula that can be used that would allow for the easy determination of potential emissions. The challenge lies in how EPA and various state agencies interpret the term "potential to emit." Under the current set off interpretations, emissions are to be calculated with the assumption that all equipment in a facility is run at its maximum hourly design or production capacity 24 hours a day, 365 days per year, or 8,760 hours per year. The interpretation does not recognize any downtime required for maintenance, equipment set up, or in process production problems such as paper jams. The interpretation also does not allow for time spent cleaning the press either during the run or when inks or other input materials must be changed. In other words, calculations require the assumption that the press is both printing and being cleaned at the same time with no reduction in emissions allowed for the time required to change plates, inks, and other materials or settings during new job set ups.

However, the definition does allow for some flexibility in that any inherent physical limitations shown too negatively limit the maximum material consumption rate can be used to reduce the emissions. For example, it is difficult to run a press at its maximum rated speed due to product quality issues, substrate, and other production related factors. Also, any equipment that reduces emissions of pollutants and is an integral component of a production line can also be used to reduce potential emissions. For example, the emissions reduced via a combination dryer/control device in a heatset web offset lithographic press can be used in the potential emission calculations. Lastly, any applicable regulation requiring a specific reduction in emissions or limits on input materials, such as inks, fountain solutions, or cleaning solvents or any other limit imposed through a federally enforceable permit can be used to reduce the potential emission calculations.

Since there is no specific guidance from EPA on how to determine potential emissions from the printing industry, this has caused confusion on the part of both printers and state/local permitting authorities with respect to the proper approach to be used. The printing industry is currently working with EPA on this issue, and some guidance on the subject was released in April 1998. This guidance is significant because it establishes that printers who emit less than 50% of the major source threshold in their area are not capable of emitting enough pollution to be considered a "major" source. Being considered a major source would require them to obtain either a Title V or federally enforceable state operating permit (FESOP). FESOPs are also known as synthetic minor or "cap" permits.

For small printers, a "cap" approach set at a 50% threshold of the major source definition based on actual emissions without control devices was established. To further simplify determinations for small printers, the emission caps were translated into a consumption level for one or more "environmental indicators." Indicators were established for each printing process category and for key input materials. For nonheatset web presses, the key input materials are fountain solution additives and cleaning solvents. For a copy of the policy and technical support document see the links at the end of the fact sheet.

In order for a printer to take advantage of EPA's policy, they need to have a provision in their state regulations or air permit recognizing the less than 50% actual emission approach. Printers that want to take advantage of EPA's policy need to contact their state regulatory agency to confirm the acceptability of this approach. If the state does not have a provision, then the approach outlined in the policy cannot be utilized.

In addition, if the actual emissions are greater than 50% of the major source threshold in your area, this also prohibits using EPA's new policy. For this situation, potential emissions will have to be determined by using the approach described above. In an effort to provide additional clarification on this issue, a position paper advancing a more realistic approach to determining potential emissions was submitted to EPA by the printing industry trade associations. The paper reviewed the problems associated with the current interpretation and supported using the following approach:

Annual Potential Emissions = Total Actual VOC Emissions
X
8,760 Hours **
Actual Operating Hours * Year

*or Annual Operating Limit Per An Existing Permit

**Actual hours of operation includes all hours that the presses ran including that portion of makeready that involves either solvent use and ink/fountain solution consumption.

Some state agencies have already accepted this approach for printers. If this approach is to be used, it is imperative that its acceptability be confirmed. Otherwise, there is a risk of possible enforcement action, especially if the proper documentation or permits have not been obtained.

Example of VOC Emission Calculation Using Above Approach and Worksheet

Material Annual Usage VOC Content
Nonheatset Web Ink, Process 25,200 pounds 35% by weight
Fountain Solution Concentrate 420 pounds 0.717 pounds/gallon
Fountain Solution Additive 120 gallons 6.7 pounds/gallon
Cleaning Solution - Blanket Wash 1,200 gallons 6.24 pounds/gallon
Cleaning Solution - Roller Wash 300 gallons 5.9 pounds/gallon
Coating - UV 180 gallons 8.5 pounds/gallon
Coating - Conventional 6,000 pounds 35% by weight

 

Material1 Usage2 Units VOC Content3 Units Release Factor4 VOC Emissions5
Ink 25,200 Pounds/Yr 0.35 % by Weight 0.05 441
Fountain Solution (FS) Concentrate 420 Gallons/Yr 0.717 Lbs VOC/Gal 1 301.14
FS Additive 120 Gallons/Yr 6.7 Lbs VOC/Gal 1 804
Cleaning Solution 1,200 Gallons/Yr 6.24 Lbs VOC/Gal 0.5 3,744
300 Gallons/Yr 5.9 Lbs VOC/Gal 0.5 885
Gallons/Yr Lbs VOC/Gal
Coatings – UV 180 Pounds/Yr 8.5 % by Weight 0 0
Coating –Conventional 6,000 Gallons/Yr 0.35 Lbs VOC/Gal 0.05 105
Gallons/Yr Lbs VOC/Gal
Misc. Gallons/Yr Lbs VOC/Gal
Total VOC Emissions 6,280 lbs/yr 3.14 tons/yr

Potential Emissions

For this example, it is assumed that the facility operated 250 days (5 days/week for 50 weeks) with two shifts or 16 hours per day. Of the 16 hours, 4 are spent in makeready activities where cleaning solvent or ink is not being used resulting in actual crewed hours of 3,000 hours/year.

Total VOC Annual Potential Emissions = 31.4 Tons / Year
X
8,760 Hours
3000 Hours / Year Year

Total VOC Annual Potential Emissions = 9.17 Tons / Year

HAP Emission Calculation Worksheet For Nonheatset Web Offset Lithographic Printing

The following worksheet presents both the formulas and assumptions that can be used to determine both actual and potential HAP emissions from nonheatset web offset lithographic printing operations. The assumptions on retention and release factors are taken directly from the EPA documents described earlier.

Material Usage1 Units HAP Content2 Units Release Factor3 HAP Emissions4
Ink Pounds/Yr % by Weight
Fountain Solution (FS) Concentrate Gallons/Yr Lbs HAP/Gal
 
 
 
 
FS Additive Gallons/Yr Lbs HAP/Gal
 
 
 
 
Cleaning Solution Gallons/Yr Lbs HAP/Gal
Gallons/Yr Lbs HAP/Gal
Gallons/Yr Lbs HAP/Gal
Coating Pounds/Yr % by Weight
Gallons/Yr Lbs HAP/Gal
Gallons/Yr Lbs HAP/Gal
Misc. Gallons/Yr Lbs HAP/Gal
Total HAP Emissions
  1. Usage is defined as purchase amount minus change in standing inventory, minus the amount that is discarded.
  2. List either percent HAP content (by weight) or pounds of HAP per gallon for the product.
    1. The HAP content information may be provided by the supplier via the Material Safety Data Sheet or USEPA Method 311 analysis. Total HAP content may have to be estimated by summing individual HAP concentrations and/or multiplying it by the density.
    2. For total HAP content determination indicate total HAP content for the material.
    3. For individual HAPs content determination, indicate the individual HAP under the material heading and its respective concentration in the HAP concentration column.
    4. For ink HAP content, use the highest HAP containing ink in each category. Note: There should not be any HAPs in offset lithographic inks. Confirm with supplier.
  3. Use the following for the appropriate HAP release factor*:

    Ink 0.05
    Fountain Solution Concentrate 1
    Fountain Solution Additive 1
    Cleaning Solution** 0.5
    Coating
    UV 1
    Water-based 1
    Conventional 0.05


    * Since all the HAPs used in offset lithography are VOCs, the same release factors will apply.

    ** The VOC composite vapor pressure of the cleaning solution cannot exceed 10 mm Hg at 20oC (68oF). Alternatively, the VOC content of the cleaning solution cannot exceed 30% by weight.
  4. The HAP emissions are determined by multiplying the Usage, HAP Content, and Release Factors together. The total HAP emissions are the result of adding all of the individual HAP emission determinations together. To convert the total pounds per year into tons per year, divide the total pounds by 2,000 because there are 2,000 pounds in one ton.

Annual Potential Emissions (APE)

To determine potential HAP emissions using the following formula:

Annual Potential Emissions = Total Actual VOC Emissions X 8,760 Hours **
Actual Operating Hours * Year

*or Annual Operating Limit Per An Existing Permit

**Actual hours of operation includes all hours that the presses ran including that portion of makeready that involves either solvent use and ink/fountain solution consumption.

Some state agencies have already accepted this approach for printers. If this approach is to be used, it is imperative that its acceptability be confirmed. Otherwise, there is a risk of possible enforcement action, especially if the proper documentation or permits have not been obtained.

List of HAPs Most Common to the Lithographic Printing Industry

The following list of HAPs can be found in materials used in nonheatset web offset printing and is provided to assist in the identification of HAPs. A complete list of HAPs is included in this fact sheet and the applicant needs to compare it with materials actually or possibly used on press.

HAP CAS Number Material
Cumene 98828 Blanket Conditioner Blanket/Roller Wash
Ethyl Benzene 100414 Metering Roller Cleaner Blanket/Roller Wash
Ethylene Glycol 107211 Fountain Solution
n-Hexane 110543 Spray Adhesive
Naphthalene 91203 Blanket/Roller Wash
Methanol 67561 Stay Open
Methyl Chloroform (1,1,1-Trichloroethane) 71556 Blanket/Roller Wash
Methylene Chloride (Dichloromethane) 75092 Metering Roller Cleaner Blanket/Roller Wash
Methyl Ethyl Ketone 79345 UV Cleaning Solution
Toluene 108883 Metering Roller Cleaner Blanket Wash
Xylene 1330207 Blanket Conditioner Blanket/Roller Wash

 

Glycol Ethers CAS Number Material
Ethylene Glycol Monomethyl Ether (2-Methoxyethanol) 109864 Fountain Solution Blanket/Roller Wash
Ethylene Glycol Monoethyl Ether (2-Ethoxyethanol) 110805 Fountain Solution Blanket/Roller Wash
Ethylene Glycol Dimethyl Ether (1, 2-Dimethoxyethane) 110714 Fountain Solution Blanket/Roller Wash
Diethylene Glycol Mono-n-Butyl Ether (Butyl Carbitol) 112345 Fountain Solution Blanket/Roller Wash
Diethylene Glycol Monomethyl Ether (2-(Methoxyethoxy) Ethanol) 111773 Fountain Solution Blanket/Roller Wash
Diethylene Glycol Monoethyl Ether (2-(Ethoxyethoxy) Ethanol) 110900 Fountain Solution Blanket/Roller Wash
Diethylene Glycol Dimethyl Ether (2-Methoxyethyl Ether) 111966 Fountain Solution Blanket/Roller Wash
Diethylene Glycol Diethyl Ether (2-Ethoxyethyl Ether) 112367 Fountain Solution Blanket/Roller Wash

The following chemicals are not to be included in the Glycol Ethers Category:

Chemical
CAS Number
Diethylene Glycol
111466
Propylene Glycol Methyl Ether
107982
Dipropylene Monomethyl Ether
34590948
All Other Propylene Glycol Ethers
Propylene Glycol Methyl Ether Acetate
108656

Example of HAP Emission Calculation Using Above Approach and Worksheet

Material Annual Usage HAP Content
Nonheatset Web Ink, Process 25,200 pounds 0% by weight
Fountain Solution Concentrate (Ethylene Glycol) 420 gallons 0.717 pounds/gallon
Fountain Solution Additive
(2-Butoxyethanol)
(Ethylene Glycol)
120 gallons 6.7 pounds/gallon
5.5 pounds/gallon
1.2 pounds/gallon
Cleaning Solution - Blanket Wash
(Naphthalene)
(2-Butoxyethanol)
1,200 gallons 6.24 pounds/gallon
2.3 pounds/gallon
1.1 pounds/gallon
Cleaning Solution - Roller Wash
(Naphthalene)
300 gallons 5.9 pounds/gallon 1.2 pounds/gallon
Coating - UV 180 gallons 0.0 pounds/gallon
Coating - Conventional 6,000 pounds 0% by weight

 

Material Usage1 Units HAP Content2 Units Release Factor3 HAP Emissions4
Ink 25,200 Pounds/Yr 0 % by Weight 0
Fountain Solution (FS) Concentrate
Ethylene Glycol 420 Gallons/Yr 0.717 lbs HAP/Gal 301.14
FS Additive
2-Butoxyethanol 120 Gallons/Yr 5.5 lbs HAP/Gal 660
Ethylene Glycol 120 Gallons/Yr 1.2 lbs HAP/Gal 144
Cleaning Solution BW
Naphthalene 1200 Gallons/Yr 2.3 lbs HAP/Gal 0.5 1,380
2-Butoxyethanol 1200 Gallons/Yr 1.1 lbs HAP/Gal 0.5 660
Cleaning Solution RW
Naphthalene 300 1.2 0.5 180
Coating Conventional 6,000 Pounds/Yr 0 % by Weight 0
Coating UV 180 Gallons/Yr 0 lbs HAP/Gal 0
Total HAP Emissions 3,325 lbs/yr 1.66 tons/yr

Individual HAP Emissions

CAS Number
Lbs/Yr
Tons/Yr
2-Butoxyethanol 111762 1,320 0.66
Ethylene Glycol 107211 445 0.22
Naphthalene 91203 1,560 0.78

Potential Emissions

For this example, it is assumed that the facility operated 250 days (5 days/week for 50 weeks) with two shifts or 16 hours per day. Of the 16 hours, 4 are spent in makeready activities where cleaning solvent or ink is not being used resulting in actual crewed hours of 3,000 hours/year.

Total Hazardous Air Pollutants Annual Potential Emissions = 1.66 Tons / Year
X
8,760 Hours
3000 Hours / Year Year

Total HAP APE = 4.85 Tons/Year
2-Butoxyethanol APE = 1.93 Tons/Year
Ethylene Glycol APE = 0.64 Tons/Year
Naphthalene APE = 2.28 Tons/Year

References

  1. Draft CTG - Control of Volatile Organic Compound Emissions from Offset Lithographic Printing, September 1993 is available at www.epa.gov/ttn/atw/print/printpg.html under Closely Related Rules, Policies or Program Guidance
  2. Alternative Control Techniques Document: Offset Lithographic Printing (EPA-453/R-94-054), June 1994 is available at www.epa.gov/ttn/atw/print/printpg.html under Closely Related Rules, Policies or Program Guidance
  3. PrintSTEP workbooks are available through www.epa.gov/compliance/assistance/sectors/printstep.html under PrintSTEP Products.
  4. Potential to Emit (PTE) Guidance for Specific Source Categories -Memo and Attached Technical Support Document are available at www.epa.gov/ttn/oarpg/t5pgm.html - scroll down to item dated 4-14-98.
  5. EIIP Volume III, Chapter 7 on Graphic Arts is available at www.epa.gov/ttn/chief/eiip/techreport/volume03/iii07.pdf

Specific questions about technology, equipment, vendors can be posted on the PrinTech listserv. To subscribe, simply follow the instructions on the PNEAC web site at www.pneac.org.

For more information or to contact someone from PNEAC please visit www.pneac.org and post your request using "Ask PNEAC".

Primary Author

Gary Jones
Graphic Arts Technical Foundation
GJones@printing.org
412.741.6860

Other PNEAC Contacts

Debra Jacobson
University of Illinois Sustainable Technology Center
djacobson@istc.illinois.edu
630.472.5019

Wayne Pferdehirt
Solid & Hazardous Waste Education Center
pferdehi@epd.engr.wisc.edu
608.265.2361

Written: November 2004
Updated: June 15, 2011

Note: Reasonable effort has been made to review and verify information in this document. Neither PNEAC and it's partners, nor the technical reviewers and their agencies, assume responsibility for completeness and accuracy of the information, or it's interpretation. The reader is responsible for making the appropriate decisions with respect to their operation, specific materials employed, work practices, equipment and regulatory obligations. It is imperative to verify current applicable regulatory requirements with state and/or local regulatory agencies.

© 2004 PNEAC