SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix H: DRAFT Emission Factor October 21, 2010 

 H-1 Final Draft Staff Report with Appendices For 

Revised Proposed Amendments to Rule 4570 

APPENDIX H 

DRAFT REVISION OF THE DAIRY VOC EMISSIONS FACTOR FOR 

REVISED PROPOSED RULE 4570 (CONFINED ANIMAL FACILITIES) 

October 21, 2010 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT 

Appendix H: DRAFT Emission Factor October 21, 2010 

 H-2 Final Draft Staff Report with Appendices For 

Revised Proposed Amendments to Rule 4570 

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San Joaquin Valley 

Unified Air Pollution Control District

San Joaquin Valley 

Air Pollution Control District 

Air Pollution Control Officer’s Revision 

of the Dairy VOC Emissions Factor 

January 2010 

Authors:

Sheraz Gill, Supervising Air Quality Engineer 

Ramon Norman, Air Quality Engineer II 

Reviewed by:

Dave Warner, Director of Permit Services 

Appendix H October 21, 2010

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DRAFT DAIRY EMISSIONS FACTOR REPORT 

Introduction

This report provides the bases for the District’s revision to the District’s Volatile 

Organic Compound (VOC) emissions factor for dairies, which was previously 

established on August 1, 2005 in the report, entitled “Air Pollution Control 

Officer’s Determination of VOC Emission Factors for Dairies”

1

. The emissions 

factor explained in this document will be used for permitting dairies in the San 

Joaquin Valley. 

This document lists some of the previous studies that were analyzed to develop 

the current dairy VOC emissions factor and reviews the more recent studies that 

were not available to the District during the previous process. It includes a 

summary of the analyses performed by the District that resulted in the 

determination of the District’s Dairy VOC emissions factor, as well as 

recommendations for further research necessary to continue to improve our 

understanding of VOC emissions from dairy operations. 

Accurate dairy emission factors are required for the proper implementation 

of applicable air quality regulations and also for the evaluation of 

appropriate technologies and practices to reduce emissions. Dairy VOC 

emissions factors are needed to implement the requirements of State law. Under 

State law (SB 700, Florez 2003) agricultural operations, including dairies, that 

have emissions greater than 1⁄2 of any of the major source thresholds are 

required to obtain air district permits. In order to determine which operations 

exceed this level of emissions, accurate VOC emission factors are needed. 

Emissions factors for the specific processes at dairies are also needed to 

evaluate and revise Best Available Retrofit Control Technology (BARCT) for 

existing dairies as required under the District’s attainment plan and to evaluate 

and establish Best Available Control Technology (BACT) for new and expanding 

dairies to comply with the requirements of New and modified Source Review 

(NSR). The magnitude of the emissions factor will be one of the several factors 

that are considered when establishing the final BARCT and BACT requirements. 

The District, through a public process, will also fully examine the technological 

feasibility, availability, and cost of possible control measures that may be 

required.

San Joaquin Valley Air District staff members have gained a great deal of 

experience in the evaluation of emissions from agricultural sources 

through collaborative efforts with other institutions, agencies, and 

interested stakeholders. Technical methodologies for determining agricultural 

emissions that were compiled and developed by Valley Air District engineers and 

specialists are currently being used by air quality agencies throughout California 

to establish permitting requirements for agricultural sources, determine the 

applicability of requirements under Title V of the Federal Clean Air Act, and 

 

1

 San Joaquin Valley Air Pollution Control District (APCO), August 1, 2005. Air Pollution Control 

Officer’s Determination of VOC Emission Factors for Dairies 

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develop air quality attainment plans. Additionally, members of the Valley Air 

District have been thoroughly involved with recent and ongoing collaborative 

scientific research efforts to evaluate emissions from agricultural sources. This is 

particularly true of the agricultural emissions research efforts that have been 

ongoing in California. The extent of Valley Air District involvement in agricultural 

research efforts includes providing recommendations on the allocation of funds; 

evaluating test methods and protocols to quantify emissions from agricultural 

sources; identifying important areas in which further research is needed; 

evaluating and commenting on study proposals; working with other parties to 

lead research projects; and interpretation of the data obtained. These research 

efforts require coordination between air quality agencies, research institutions, 

independent researchers, and agriculture. The Valley Air District plays an 

important role in these essential coordination efforts through the Ag-Tech 

Committee and the Dairy Subcommittee. 

The revised VOC emissions factor for dairies proposed in this report is 

based on a detailed review of the available science. There have been 

significant additional scientific researches conducted since the development of 

the initial emission factor in the report by the APCO, dated August 1, 2005. 

These additional studies have been conducted with greater focus on processes 

and compounds of interest and were also designed to be more reflective of 

conditions found at California dairies. The District will cross reference these new 

studies with the studies that were used to develop the initial emission factor. As 

would be the case with emissions factors for other sources, the District’s dairy 

emissions factor will be revised to reflect the latest scientific information that is 

currently available. 

In revising the dairy emissions factor, the District will continue to adhere to the 

sound guiding principles which were used to establish the District’s original dairy 

emissions factor. Continued adherence to these principles ensures that the 

revised dairy emissions factor is supported by best available science. 

In evaluating the latest research studies, studies performed on California 

dairies and in conditions representative of California conditions were 

always given preference. The revised dairy emissions factor is entirely based 

on results from studies of California researchers at California dairies. The 

District’s previous emission factor was also predominantly based on California 

research. However, because at the time there was not adequate California 

research to quantify emissions of volatile fatty acids (VFAs), studies from outside 

of California (Hobbs et al and Koziel et al) were previously used to calculate 

emissions of these compounds from dairy waste. In establishing the revised dairy 

emissions factor, these studies have been replaced with more recent studies on 

enteric VFA emissions from dairy cattle conducted by Dr. Frank Mitloehner from 

UC Davis and studies on total VOC emissions from various dairy processes 

conducted by Dr. Chuck Schmidt, a private consultant based in California. This 

draft report also uses California emission studies to quantify emissions from dairy 

3

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feed, an important emissions source for which there was previously insufficient 

research. 

The District continues to support continued and ongoing research at 

California dairies to further refine and supplement these emission factors. 

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Background

The San Joaquin Valley Air Basin has an inland Mediterranean climate 

characterized by hot, dry summers and cool, foggy winters. The San Joaquin 

Valley is surrounded by mountains on the east, west, and south sides. This 

creates stagnant air patterns that trap pollution, particularly in the south of the 

San Joaquin Valley. Additionally, the sunshine and hot weather, which are 

prevalent in the summer, lead to the formation of ozone (photochemical smog). 

Because of the San Joaquin Valley’s geographic and meteorological conditions, 

it is extremely sensitive to increases in emissions and experiences some of the 

worst air quality in the nation. 

The San Joaquin Valley Air Basin is currently classified as a serious nonattainment area for the health-based, Federal eight-hour ozone standard. 

However, EPA has been requested to reclassify the air basin as an extreme nonattainment area for the eight-hour ozone standard because of the inability to 

reach attainment of the standard by the earlier serious and severe classification 

attainment dates using currently available technologies and this reclassification is 

expected to occur in the near future. The air basin is also classified as a nonattainment area for the Federal PM-2.5 (ultra-fine particulate matter) standard. 

Purpose of the San Joaquin Valley Air Pollution Control District 

The San Joaquin Valley Air District is a public health agency whose mission is to 

improve the health and quality of life for all Valley residents through efficient, 

effective and entrepreneurial air quality management strategies. To protect the 

health of Valley residents, the District works toward achieving attainment with 

health-based ambient air quality standards as required under State and Federal 

law. To achieve this goal, the District develops and adopts air quality attainment 

plans that include control measures aimed at further reducing emissions from a 

broad range of sources, including agriculture. 

As mandated by Federal Law, the San Joaquin Valley Air District adopted its 

2007 ozone attainment plan to demonstrate how the Valley would reach 

attainment with the Federal eight-hour ozone standard. In developing the ozone 

attainment plan every feasible measure to reduce emissions of ozone precursors 

(VOC and NOx) was explored. However, even though the District will be 

requiring every practical VOC and NOx control, and will be relying on the state 

and federal governments to significantly reduce emissions from mobile sources 

of pollution, the San Joaquin Valley will still need the development and adoption 

of future, not-yet-developed, clean air technologies to reach attainment by the 

2023 deadline. Achieving the goal of attainment with air quality standards will 

require continued contributions from all industries, businesses, and individuals in 

the San Joaquin Valley. 

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Permitting Requirements 

A critical tool that the air districts use to limit increases in emissions of air 

pollutants and to assure compliance with air quality regulations is the issuance of 

conditional construction and operating permits to commercial and industrial 

sources of air pollution. Since the 1970s, the San Joaquin Valley Air Pollution 

Control District and its predecessors have issued tens of thousands of 

conditional permits that are being used to assure compliance with air pollution 

control requirements throughout the Valley. District permits address the 

requirements of federal standards, state regulations, and District rules that 

specifically apply to a source of air pollution. New and modified sources of air 

pollution are also subject to the more protective requirements of “New Source 

Review”, which are determined on a case-by-case basis and are also included in 

the permit. Permit holders, District Inspectors, and others use these District 

permits, rather than directly reference the complex and voluminous underlying 

regulations, to verify compliance with applicable air quality requirements. 

Removal of the Agricultural Exemption from Permitting 

Under California state law, agricultural sources of air pollution, including dairies, 

were previously exempt from air district permitting requirements and new source 

review emissions limitations. This exemption was removed effective January 1, 

2004, when Senate Bill 700 (Florez) amended the California Health and Safety 

Code to eliminate the longstanding permit exemption for agricultural operations 

that grow crops or raise animals. With the elimination of the agricultural permit 

exemption, San Joaquin Valley dairies also became subject to “New Source 

Review” requirements, including the requirement to apply Best Available Control 

Technology (BACT) to new and expanding operations. 

San Joaquin Valley Dairies and Air Quality 

Dairies are significant sources of smog-forming Volatile Organic Compounds 

(VOCs) and fine particulate matter in the San Joaquin Valley. Volatile Organic 

Compounds are emitted directly from the Valley’s approximately 2.5 million dairy 

cows2

, from the fermentation and decomposition of cattle feed, and from the 

decomposition of the waste excreted each day from dairy cows in the San 

Joaquin Valley. Dairies are among the largest sources of VOCs in the Valley, 

and these smog-forming VOC emissions have a significant adverse impact on 

efforts to achieve attainment with health-based air quality standards. 

VOC Emissions Factors for Dairies 

When agricultural sources in California first became subject to air district 

permitting requirements on January 1, 2004, there was very little data available 

 

2

 USDA, National Agricultural Statistics Service. 2007 Census of Agriculture – County Data, Table 

11 – Cows and heifers that had calved 

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that could be used to quantify Volatile Organic Compounds (VOC) emissions 

from confined animal facilities, such as dairies. To calculate VOC emissions from 

dairies, EPA and the California Air Resources Board (ARB) used a VOC 

emissions factor of 12.8 lb/head-yr based on the very limited information that was 

available. Subsequently, California air districts, including the San Joaquin Valley 

Air Pollution Control District, adopted this VOC emissions factor for dairy 

permitting and emissions inventory purposes. However, the basis for the 12.8 

lb/head-yr VOC emission factor was an older study performed in the 1930s that 

only measured methane emissions from dairy cows in environmental chamber 

tests. Volatile Organic Compounds emissions were not directly determined in the 

tests but were estimated using an assumed ratio of VOCs to total organic gasses 

with the methane emission measurement values used as total organic gas 

emissions. Additionally, the 1930 chamber tests did not represent the majority of 

dairy processes. Because of the age of the original study and the many 

assumptions that were needed to derive the dairy VOC emissions factor, there 

was a great deal of uncertainty as to whether the 12.8 lb/head-yr emissions 

factor accurately reflected VOC emissions from dairy cows and dairy processes 

and was scientifically defensible. 

As such, the District revised the dairy emission factor in its report entitled, “Air 

Pollution Control Officer’s Determination of VOC Emission Factors for Dairies”

1

which was released on August 1, 2005 and resulted in a revised dairy VOC 

emissions factor of 19.3 lb/hd-day. This is the emissions factor that the District 

currently uses for permitting dairy operations in the San Joaquin Valley. This 

emissions factor was based on a thorough review of the scientific research 

available and represents a significant improvement compared to the previous 

value of 12.8 lb/head-yr. However, the emissions factor report identified several 

dairy processes and compounds for which additional research was needed to 

accurately quantify emissions. This second revision is brought about because of 

an accumulation of significant additional scientific research on the majority of 

sources of emission at a dairy, specifically at those sources where no data were 

available the first time around. 

Deferral of Permit Requirements for Some Smaller Operations 

Under SB 700, permitting requirements were deferred for smaller agricultural 

operations with emissions less than one-half of the major source thresholds. 

Based on the original dairy VOC emission factor of 12.8 lbs/hd-yr, existing dairies 

with 1,954 cows3 were estimated to have VOC emissions equal to or greater 

than one-half of the District major source threshold, and were required to apply 

for District permits by June 30, 2004. Dairies with less than 1,954 cows were 

determined to have emissions less than one-half of the major source threshold; 

 

3

 The 1,954 number is an estimated threshold assuming all cows on the dairy emit VOCs at the 

same rate as milk cows, which is not the case. The actual threshold (generally above 1,954) must 

be determined on a case-by-case basis and varies with the number of milk cows, dry cows, 

heifers, and calves on the dairy. 

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therefore, District permitting for these smaller dairy operations was not initially 

required. However, on August 1, 2005 the District revised the Dairy VOC 

emissions factor from 12.8 lb/head-yr to 19.3 lb/head-yr using the best available 

science. As a result of the revised emissions factor, dairies with more than 1,190 

milk cow (or an equivalent mix including support stock) became subject to District 

permits after August 1, 2005. 

Additionally, under the provisions of SB 700, an air district may permit smaller 

sources by making the following findings in a public hearing: 

1) A permit is necessary to impose or enforce reductions in emissions of 

air pollutants that the district shows causes or contributes to a violation of 

a state or federal ambient air quality standard. 

2) The requirement for a source or category of sources to obtain a permit 

would not impose a burden on those sources that is significantly more 

burdensome than permits required for other similar sources of air 

pollution. 

The District did, in fact, make these findings during its adoption of District Rule 

4570 – Confined Animal Facilities (CAF). The District determined that to ensure 

enforceability of the VOC mitigation measures required by state law and the 

District’s attainment plans, agricultural facilities subject to the rule required 

District permits. As determined by the California Air Resources Board (CARB), a 

dairy with 1,000 milk cows or more is defined as a large CAF. Therefore, any 

dairy with 1,000 or more milk cows is also currently subject to District permits. 

It should be noted that agricultural sources of air pollution do not become subject 

to District permitting, “New Source Review” (NSR), or Best Available Control 

Technology (BACT) requirements until the emissions from these sources exceed 

one-half of the major source threshold values, which is currently 12.5 tons 

(25,000 lbs) of NOx or VOC, but will be reduced to 5 tons (10,000 lbs) of NOx or 

VOC after EPA approval of re-designation of the San Joaquin Valley as Extreme 

Nonattainment for the Federal 8 hour ozone standard. For non-agricultural 

source categories, District permits and BACT are generally required at the far 

lower emissions rate of greater than 2 lb/day. For numerous years, permits and 

significant air pollution controls have been required for much smaller sources of 

emissions such as print shops, autobody shops, gasoline stations, and dry 

cleaners. 

Authority to Construct Permitting Requirements for Dairies Constructed or 

Modified after 1/1/2004 

As well as requiring operating permits for existing dairies, SB 700 also required 

dairies with emissions greater than one-half the major source thresholds that 

were constructed or modified on or after 1/1/2004 to obtain Authority to Construct 

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permits from the District prior to commencing construction. These new and 

modified dairies, like all other new and modified sources of air pollution, are 

subject to the requirements of the District’s New and Modified Stationary Source 

Review Rule (District Rule 2201), including the requirement to apply BACT, and 

may potentially be required to offset emission increases once protocols are in 

place to allow agricultural sources to bank Emission Reduction Credits from 

qualified emission reductions. 

Large CAF Rule for Existing Dairies 

In addition to the Air District permitting requirements described above that 

resulted from the elimination of the agricultural exemption, Section 40724.6 of the 

Health and Safety Code required the California Air Resources Board (ARB) to 

develop a definition for the source category of "large" Confined Animal Facilities 

(CAF) that would be subject to VOC control requirements. In developing the large 

CAF definition, ARB was required to review relevant scientific information, 

including potential air quality impacts, the effects that confined animal facilities 

may have on the attainment and maintenance of air quality standards, and 

applicable livestock emission factors. This section of the Health and Safety Code 

also required the District to adopt a rule establishing VOC control requirements 

for large CAFs, including dairies. 

On June 23, 2005, at the conclusion of a public hearing, ARB adopted Resolution 

05-35, which established the definition of large Confined Animal Facilities. The 

definition adopted by ARB specifies that dairies with 1,000 or more milk cows 

that are in a region designated as a federal ozone nonattainment area as of 

January 1, 2004 are large CAFs and that dairies in all other areas with 2,000 or 

more milk cows are large CAFs. Because of the San Joaquin Valley Air Basin’s 

status as a federal ozone nonattainment area, dairies in the Valley with 1,000 or 

more milk cows are large CAFs. On June 15 2006, the District adopted Rule 

4570 – Confined Animal Facilities to require existing large CAFs to begin to 

implement VOC control requirements that are suitable to each particular 

operation. District Rule 4570 included various options and management practices 

that could be used to achieve the required emission reductions from different 

sources at confined animal facilities, such as feed storage and handling, animal 

housing, manure handling and storage, and lagoons. The District has issued 

Authority to Construct permits to over 600 confined animal facilities, including 

over 500 dairies, to implement various mitigation measures and practices to 

reduce VOC emissions from these facilities. District Rule 4570 has resulted in 

more than 20 tons per day of emission reductions of smog-forming VOCs in the 

San Joaquin Valley. 

The District recently began the process to amend the existing version of Rule 

4570 to achieve further reductions from existing confined animal facilities in order 

to attain compliance with applicable health-based ambient air quality standards. 

The amendments may involve lowering the applicable threshold and/or requiring 

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additional practices to reduce VOC emissions. Using the most accurate 

emissions information available will be critical to the District’s process to amend 

Rule 4570. The revised dairy emission factor proposed in this document will 

allow for a more accurate assessment of sources that contribute to emissions at 

a dairy and allow these emission sources to be targeted for cost-effective 

emission control strategies. 

Important Findings from Latest Dairy Emissions Research 

Recent dairy emission research studies performed under the direction of 

California air quality agencies and stakeholders have significantly increased 

knowledge of dairy emissions and also shed some light on potential strategies to 

reduce these emissions. Recently completed California dairy emission studies of 

note include: 

• A study at UC Davis, led by Dr. Frank Mitloehner, entitled “Volatile Fatty 

Acids, Amine, Phenol, and Alcohol Emissions from Dairy Cows and Fresh 

Waste”

4

. This study measured emissions of alcohols, volatile fatty acids, 

and amines directly from lactating and dry cows and also from their fresh 

manure. This study provides valuable information on enteric emissions 

from cattle as well as emissions from freshly excreted manure. 

o The original study performed by Dr. Mitloehner (May 2006) was 

found to have incorrect data due to the lack of an ammonia filter in 

the Innova measurement device. The lack of an ammonia filter 

resulted in significant interference when measuring alcohols; 

therefore, readings of ammonia emissions were incorrectly 

recorded as alcohol emissions. In order to obtain accurate data; Dr. 

MItloehner recreated the entire study with the proper filters in place. 

The study was recently completed (October 2009) and as such, a 

final report has not been generated. At the request of District staff, 

the resulting data, minimal but sufficient, has been provided by the 

researcher to the District so that emissions can be estimated5

. 

• Two studies conducted by Dr. Chuck Schmidt, (Dairy emissions using flux 

chambers, 2006, Phase III6

 and 2009, Phase IV7) which measured 

various emission compounds along with total VOCs from dairy waste and 

feed. The emission measurements were taken from silage piles, bunker 

feed (Total Mixed Ration (TMR)), lagoons, manure piles, corrals, flush 

lanes, solid manure application and liquid manure application. This 

information will be used to develop estimates of annual emissions from 

important sources such as corrals, silage piles, and total mixed ration. 

 

4

 Mitloehner, Frank, May 2006. Volatile Fatty Acids, Amine, Phenol, and Alcohol Emissions from 

Dairy Cows and Fresh Waste from Environmental Chambers 

5

 Mitloehner, Frank, 2009. Revision of May 2006 Study- Alcohol Emissions from Dairy Cows and 

Fresh Waste from Environmental Chambers (data set only) 

6

 Schmidt, C.E. 2006. Results of the Dairy Emissions Evaluation Using Flux Chambers Phase III 7

 Schmidt, C.E. 2009. Results of the Dairy Emissions Evaluation Using Flux Chambers Phase IV

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• A series of studies led by Dr. Charles Krauter in which flux chambers were 

used to evaluate VOC emissions from sources at two dairies in the San 

Joaquin Valley8. The emission measurements were taken from many 

sources at the dairy including the corrals, flush lanes, lagoons, feed 

storage areas, and Total Mixed Ration (TMR). Seasonal and diurnal data 

were also taken for certain sources during the flux chamber studies. 

Important findings of the latest dairy research studies include: 

• Manure storage ponds and lagoons, which were previously thought to be 

a major source of VOC emissions at dairies, now appear to emit a 

comparatively small fraction of the overall dairy VOC emissions; 

• Feed at dairies is a significant source of VOC emissions. The exposed 

faces of silage piles that are used to store and preserve silage to be fed to 

the cattle and the total mixed ration placed in lanes for cattle consumption 

emit significant amounts of VOCs, particularly alcohols. 

• Emissions of alcohols (primarily ethanol) from feed, fresh manure, and 

directly from cows appear to comprise a significant fraction of dairy VOC 

emissions; 

• Manure deposited in open corrals appears to be an important source of 

VOC emissions on some dairies; 

• Emissions of volatile fatty acids (VFAs) are important but not as significant 

as previously estimated during the first revision of the dairy VOC 

emissions factor; 

• The practice of flushing freestall barns more frequently has the potential to 

reduce VOC emissions from cow housing areas. 

• Several of the compounds that have been identified as important 

components of dairy emissions, such as alcohols and volatile fatty acids, 

are highly soluble in aqueous solutions. This property may be important 

when developing potential mitigation strategies. 

• Land application of solid and liquid dairy manure contributes a relatively 

small amount to total VOC emissions at dairy. 

• Seasonal variation in emissions may be an important factor to consider 

when developing annual emission estimates. The seasonal variation in 

emission rates was observed to be more pronounced with ammonia 

emissions than VOC emissions. 

This additional research, which has been completed since the August 1, 2005 

revision to the dairy emissions factor, will be evaluated to update the current 

VOC emissions factor that is used to permit dairies in the San Joaquin Valley. 

 

8

 Krauter, Charles, January 2009. Dairy Operations: An evaluation and Comparison of Baseline 

and Potential Mitigation Practices for Emissions Reductions in the San Joaquin Valley 

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The Purpose of this Revision to the Dairy VOC Emissions Factor 

The District is charged with the responsibility of adopting emissions factors for 

various sources of air pollution in order to establish accurate emissions 

inventories for the San Joaquin Valley air basin and to develop rules and 

standards to efficiently allocate resources to reduce emissions in the most costeffective way. For sources, such as agriculture, that have only recently become 

subject to air quality regulations, there can be a lack of consensus as to the 

emissions factor that is most suitable. In these cases the District must use its 

expert judgment to evaluate the scientific information available to establish an 

appropriate emissions factor. This District did exactly this during the original 

revision to the dairy VOC emissions factor. However, as stated earlier, dairy 

emission research that better reflect the conditions at California dairies have 

recently been completed. These studies have greatly improved our knowledge of 

the emissions of compounds, such as alcohols and volatile fatty acids. These 

studies have also given us valuable, new information on emissions from 

important sources, such as dairy feed and land application, which had not 

previously been measured. The District has determined that the new information 

on dairy emissions that is contained in the latest studies must be included in the 

District’s dairy VOC emissions factor in order to accurately quantify emissions 

and assess potential mitigation strategies that may be required by BACT and the 

revised version of District Rule 4570. As with the first revision to the dairy VOC 

emission factor, the contents of this draft report will go through a public process 

in which comments on the proposed emissions factor will be addressed. 

Guiding Principles Used by the APCO for Determining Appropriate 

Emissions Factors

Dairies are fairly complex emissions sources that emit several types of VOCs 

from the different dairy processes. Because of this, it is difficult to design and 

carry out a single research effort that would measure all of the VOCs emitted. 

Therefore, in order to determine appropriate dairy emissions factors, the District 

reviewed several different studies in the first revision to the dairy VOC emissions 

factor. This current revision will reevaluate the dairy VOC emissions factor in light 

of the recently completed California dairy emissions studies. The results of these 

studies will be used to augment or replace values in the current dairy emissions 

factor for categories of dairy processes or compounds emitted for which better 

emissions research is now available. 

The following principles were utilized to evaluate studies and select appropriate 

data for revision of the dairy emissions factor: 

1. Emissions data from research studies provided by scientists, information 

of dairy emissions research, and data from available scientific literature 

were used to determine the emissions factor. 

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2. The methods used to collect the data were reviewed. Data were 

considered invalid if any of the following problems are found, unless an 

appropriate way to correct the data is available: 

a) Indications that samples may have been contaminated. 

b) Evidence that sample collection procedures may have resulted in 

the potential for significant loss of analyte. 

c) Evidence that sample storage procedures may have resulted in the 

potential for significant loss of analyte. 

d) Sample loss determined to have occurred in the analytical process 

(e.g. low laboratory spike recovery due to matrix effects) 

e) Indications of mis-calibration or excessive calibration drift. 

f) Appropriate laboratory protocols were not followed. 

g) Other uncorrectable errors were identified. 

3. When VOC data for a process or compound is available from more than 

one source, the following steps are to be followed to select the best 

available data for use in developing an emission factor: 

a) Valid data from recent tests performed at California dairies was 

given preference over data from other sources. The District will 

carefully consider specific process conditions (such as 

meteorological conditions, season, manure moisture content, 

available information on feed, etc.) in evaluating the transferability 

of out-of-state data. 

b) Data representing a specific constituent or process are to be given 

preference over data that represents a broad range of constituents 

or processes. 

c) Where test results from more than one source are deemed 

equivalent, an average emission factor is to be determined. 

4. Non-quantitative or anecdotal evidence of emissions such as compound 

concentrations measured near dairies or feedlots that could not be related 

to process parameters, or the presence of varying levels of odors near 

dairy processes, will not be used to determine emissions factors. 

5. When no valid source of quantitative VOC data that could be linked to 

dairy processes is found, no emissions factor is to be determined, and the 

constituent or process emissions factor is to be reported as “NA” or not 

available, and further research is to be recommended. 

6. When evidence indicates that significant quantities of VOC compounds 

are emitted, but the emissions cannot be quantified based on available 

data, the constituent or process emission factor is to be reported as “TBD, 

>0”, meaning To Be Determined, but known to be greater than zero, and 

further research is to be recommended. 

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DRAFT DAIRY EMISSIONS FACTOR REPORT 

Analysis

Category 1: Enteric Emissions 

Basis of Current VOC Emissions Factor 

Basis of the Current Dairy VOC Emissions Factor – Enteric Emissions 

(Previous Category 1: Emissions from Cows and Feed in Environmental Chamber) 

Process or 

Constituent 

Emissions Factor 

(lb/hd-yr) 

Basis for Current 

Emissions Factor 

Emissions from Cows 

and Feed 1.4 

Emissions from Cows and Feed in 

Environmental Chamber with analysis by 

PTR/MS (Mitloehner, 2005)9

VOC emissions from cows, feed, and fresh manure were measured in 

environmental chambers by Dr. Frank Mitloehner of UC Davis using Proton 

Transfer Reaction Mass Spectroscopy (PTRMS). VOC emissions were estimated 

to be 1.6 lb/hd-yr. Because other VOC tests by Dr. Mitloehner using EPA Method 

TO-15 had shown that emissions from fresh manure in the test chamber 

represented approximately 10% of emissions, the value for enteric and feed 

emissions without the excreta was calculated to be to 1.4 lbs/hd-yr. 

Recent VOC Emissions Studies

Recent Studies – Enteric Emissions 

Recent Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Emissions from Cows and Feed 

in Environmental Chambers with 

analysis by TDS-GC-MS, NIOSH 

2010, alcohols by INNOVA 

photoacoustic analyzers 

(Mitloehner, 2006)4

Milk Cows 

VFAs: 0.015 

Phenols/Cresols: 0.08 

The alcohol measurements were performed 

using INNOVA photoacoustic analyzers with 

no ammonia filters. It was later shown that 

ammonia present in the mixture of gases 

being measured results in inferences that 

cause measured alcohol concentrations to be 

greater than the true values. 

Alcohol Emissions from Cows and 

Feed in Environmental Chambers 

by INNOVA photoacoustic 

analyzers with ammonia filters 

(unpublished data Mitloehner, 

2009)7

Milk Cows 

Ethanol: 2.6 

Methanol: 0.03 

Preliminary Data 

 

9

 Mitloehner, Frank (study conducted in 2005, but published in 2007). Emissions from Cows and 

Feed in Environmental Chamber with analysis by PTR/MS 

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Evaluation

The California research that is currently available to quantify enteric emissions 

from dairy cows is from a series of studies conducted at UC Davis by Dr. 

Mitloehner, including a recent study that has not yet been published. Dairy cows 

were placed in controlled environmental chambers and various methodologies 

were used to quantify VOC emissions from cows and the manure deposited in 

the chambers. 

In the first environmental chamber study conducted in 2005 (published in 2007), 

Proton-Transfer-Reaction Mass Spectrometry (PTRMS) was used to quantify 

emissions from dairy cattle and fresh manure. PTRMS detected a number of 

oxygenated compounds and some volatile fatty acids. However, ethanol 

emissions were not quantified in this study because the measurement process 

converts much of the ethanol to ethane, which has a low proton affinity, and is, 

therefore, undetectable by PTRMS. Several other studies have shown that large 

quantities of ethanol are emitted from the various processes at dairies; therefore, 

the inability to measure ethanol is a significant weakness in the PTRMS data. 

However, the PTRMS measurements were used to quantify emissions for the 

August 2005 revision to the dairy emissions factor because it was the best 

information available at the time. 

In the second environmental chamber study completed in 2006, INNOVA 

photoacoustic analyzers were used to quantify ethanol and methanol emissions 

from dairy cattle and fresh manure and emissions of VFAs and phenolic 

compounds were sampled using a modified sorbent tube method and quantified 

using thermal desorption and gas chromatography (EPA TO-17). The 

instrumentation was calibrated to measure the following VFAs: acetic, propionic, 

isobutyric, butyric, isovaleric, valeric, isocaproic, caproic, and heptanoic acids 

and was calibrated to measure the following phenol and cresol compounds: 

phenol, 2-methylphenol, 2-ethylphenol, 3-methylphenol, 4-methylphenol, indole, 

and 3-methylindole. The results of this study indicated very high emissions of 

alcohols from cows and their fresh manure. However, subsequent research by 

Dr. Mitloehner has discovered that when using the INNOVA analyzer without an 

ammonia filter, significant interference occurs when measuring alcohols. 

Because the INNOVA analyzer in this study did not include an ammonia filter, 

ammonia present in the chamber was incorrectly identified as alcohols. 

Therefore, the alcohol measurements from this study are not reliable. The study 

results showed very low levels of VFAs and phenol and cresol compounds. The 

only VFAs that were detected in measurable quantities were acetic, propionic, 

and butyric acid. Acetic acid was the only VFA that was consistently above the 

Limit of Quantification and the only VFA found to measurably contribute to enteric 

VOC emissions from milk cows but this contribution was very small. The VFA 

emissions measured in this study were lower than the acetic acid values 

measured in the earlier study using PTRMS. 

 

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The third environmental chamber study was recently completed by Dr. Mitloehner 

in late 2009 and is not yet published. This study is intended to replace the alcohol 

data from the previous 2006 study. In this study INNOVA photoacoustic 

analyzers with ammonia filters were used to quantify ethanol and methanol 

emissions from dairy cattle and fresh manure. The alcohol measurements from 

this study are considered to be much more reliable than the measurements from 

the earlier study, which used INNOVA analyzers without ammonia filters. This 

study resulted in significantly lower alcohol emissions. Enteric ethanol emissions 

from milk cows were significantly lower and enteric methanol emissions from milk 

cows were nearly zero. The methanol emissions measured in this study were 

lower than the value measured in the earlier study using PTRMS. 

Conclusion

The APCO has chosen to continue to use the 1.4 lb/head-yr from PTRMS to 

quantify emissions of methanol, acetic acid, and other compounds in this 

category due to the conservative nature of the PTRMS measurement and sample 

loss. The storage and transport loss was less likely than with the sorbent tube 

method used to measure VFAs in the second chamber study. Additionally, 0.08 

lb/hd-yr will be added to represent the measured value for enteric emissions of 

phenols and cresols from the second chamber study and 2.6 lb/hd-yr will be 

added to account for the ethanol emissions measured in the third chamber study. 

Therefore, enteric VOC emissions from milk cows are determined to be 4.1 lb/hdyr. 

Category 2: Milking Parlor (waste emissions) 

California VOC Emissions Studies

 

Milking Parlor (waste emissions) 

Process or 

Constituent 

Emissions Factor 

(lb/hd-yr) 

Basis for Current 

Emissions Factor 

VOCs from Milking 

parlors 

VOCs by TO-15: 

0.02 lb/hd-yr 

Amines: 0.01 lb/hd-yr 

Flux chambers with analysis by EPA TO-15, & 

EPA TO-11 (Schmidt, 2004)10

Dr. Chuck Schmidt measured VOC emissions from a dairy milking parlor at one 

Merced County dairy using flux chambers in conjunction with EPA method TO-15 

and EPA method TO-11. The emission measurements were performed in 2004. 

The TO-15 measurements resulted in a total VOC measurement of 0.02 lb/hd-yr 

 

10 Schmidt, C.E. April 2005. Results of the Dairy Emissions Evaluation Using Flux Chambers 

Merced Dairy- Summer Testing Event 

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and amines were found to contribute an additional 0.01 lb/hd-yr. Therefore, total 

VOCs from the milking parlor were 0.03 lb/hd-yr based on this study. 

Evaluation

The VOC emissions measured from the milking parlor were found to be very low. 

This is likely the result of the high solubility of the VOCs that would be emitted. 

Milking parlors are constantly flushed with fresh water so these compounds are 

likely to remain in solution in the water rather than being emitted to the 

atmosphere. 

 

Conclusion

The only California data available to calculate VOC emissions from milking 

parlors are from Dr. Schmidt’s 2004 study; therefore, the APCO proposes an 

emissions factor of 0.03 lb/hd-yr for milking parlors. Because of the high 

solubility of VOCs emitted at dairies and the relatively small surface area of 

milking parlors, this source does not contribute significantly to total VOC 

emissions at a dairy. 

Category 3: Freestall Barns (waste emissions) 

Recent VOC Emissions Studies

Recent Studies – Freestall Barns (bedding and flush lanes) 

Recent Studies 

Emissions Factors from 

New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of 

barns (flush lanes and stalls) 

with analysis of Total ROG by 

SCAQMD 25.3 (Schmidt, 

2006)6

1.8 lb/hd-yr 

Average pre-flushed flush 

lane flux of 131 μg/m2

-min 

(Dairy 1: 158 μg/m2

-min; 

Dairy 2: 104 μg/m2

-min) 

Average bedding solids flux 

of 246 μg/m2

-min 

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

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Recent Studies – Freestall Barns (bedding and flush lanes) 

Recent Studies 

Emissions Factors from 

New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of ROG 

from flush lanes with analysis 

by GC/MS (Krauter, 2009)7

Average flush lane flux of 

187 μg/m2

-min (preflush/scrape: 353 μg/m2

-

min; post-flush/scrape: 21 

μg/m2

-min) 

Average flush lane flux 

excluding outlier: 111 - 131 

μg/m2

-min (preflush/scrape: 200 - 241 

μg/m2

-min; postflush/scrape: 21 μg/m2

-min) 

Measured by GC/MS 

1st average includes single outlier with 

higher ROG primarily due to refrigerant 

CFC-12, which was removed from second 

average flux value 

Evaluation

The recent California research that is currently available to quantify emissions 

from dairy freestall barns is from two studies conducted at dairies in the San 

Joaquin Valley. 

The first study was performed in 2005 (completed in 2006) by Dr. Chuck Schmidt 

and used flux chambers to quantify emissions at two dairies located in Merced 

County and Kings County. EPA Flux chambers were used to collect samples and 

SCAQMD Method 25.3 was used to quantify total VOC flux. Several other 

methods were also used to quantify emissions during this study, including EPA 

TO-11, EPA TO-13, EPA TO-8, BAAQMD 29, EPA TO-14, and EPA TO-15. 

SCAQMD Method 25.3, which quantifies total carbon atoms from VOCs 

excluding methane and ethane, consistently resulted in higher mass values of 

VOC as methane than the sum of the other methods when the total carbon 

measured by these methods was also converted to methane. The measured flux 

values and the surface areas of specific processes at the dairies were used to 

determine the emissions rate. The emissions rates were then divided by the 

number of cows at the dairies to arrive at the emissions factors for the dairies. 

VOC emissions measured from the flush lanes prior to flushing were low and the 

emissions flux was similar at both dairies. The original study report calculated an 

emissions factor based on the total head at the dairies. The measured flux and 

process surface areas for only the milk cow areas and estimated number of milk 

cows at the dairies in 2005 were used to calculate the VOC emissions factors 

based only on milk cows. The resulting VOC emissions factors were 0.8 lb/hd-yr 

for the flush lanes and 1.0 lb/hd-yr for the stall bedding, for a total of 1.8 lb/hd-yr 

from the freestall barns. 

A recently completed study performed by Dr. Charles Krauter measured VOC 

flux from six dairies in the San Joaquin Valley using flux chambers. EPA Flux 

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chambers were used to collect samples and GC/MS was used to quantify VOC 

flux. Sampling occurred during the winter, early summer, and fall. The report did 

not provide the surface areas of specific processes at the dairy, which are 

needed to calculate the total mass emissions rates. However, the average flux 

values from this study can be compared to the flux values obtained in Dr. 

Schmidt’s study. This study measured higher average VOC flux values for the 

flush lanes prior to flush/scrape than Dr. Schmidt’s 2005 study but also measured 

very low VOC flux from the lanes after flushing/scraping. Therefore, the overall 

averages were similar. There was one flux measurement at Dairy A that had 

several times the flux value of the next highest measurement primarily due to the 

refrigerant CFC-12, which was not found in more than trace amounts in the other 

samples. When this measurement is removed the overall average for VOC flux 

from the flush lanes is nearly the same as Dr. Schmidt’s 2005 dairy study. 

Although the study report did not provide sufficient information to calculate an 

emissions factor for the individual dairies sampled, the study did contain an 

example of emissions that could be expected from a fictitious dairy based on the 

information gathered in the study. The fictitious dairy in the report had a VOC 

emission factor of 1.0 lb/hd-yr for the flush lanes, which is very close to the value 

of 0.8 lb/hd-yr from the Dr. Schmidt’s 2005 dairy study. 

Conclusion

The APCO has determined that the total VOC measurements from Dr. Schmidt’s 

2005 study provide the best available data to quantify VOC emissions from dairy 

freestall barns. Dr. Schmidt’s 2005 dairy study measured total VOC emissions 

from both flush lanes and stalls in the freestall barns and provided the 

information needed to calculate specific emission factors for these processes. Dr. 

Krauter’s study resulted in similar average VOC flux from the freestall flush lanes. 

If the one potentially anomalous measurement is removed from Dr. Krauter’s 

study, the average VOC flux from the freestall is equivalent or less than the 

average flux determined in the Schmidt study using a different analytical method. 

Both studies indicated that VOC emissions from flush lanes are low because of 

the high solubility of many of the compounds. The flush lane VOC emissions 

factor from the data in Dr. Schmidt’s study and the VOC emissions factor for the 

fictitious dairy described in the report for Dr. Krauter’s study are nearly the same. 

Therefore, both studies clearly support each other. However, it is more 

defensible to base the emission factor on the data from Dr. Schmidt’s study 

because the surface areas used to calculate the emissions factor in this report 

were based on the processes observed at the dairies studied rather than 

approximations based on a fictitious dairy. Therefore, the APCO proposes an 

emissions factor of 1.8 lb/hd-yr for the freestall barns. 

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Category 4: Corrals (waste emissions) 

Recent VOC Emissions Studies

Recent Studies –Corrals (waste emissions) 

New Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of corrals 

with analysis of Total ROG by 

SCAQMD 25.3 (Schmidt, 2006)6

Turnout Average: 8.3 

lb/hd-yr (Average flux of 

243 μg/m2

-min) 

Seasonally Adjusted 

Turnout Average based 

on 2008 Study: 6.8

lb/hd-yr (Average flux 

of 195 μg/m2

-min) 

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Flux chamber sampling of corrals 

during summer and winter 

seasons with analysis of Total 

ROG by SCAQMD 25.3 

(Schmidt, 2009)7

Seasonally Adjusted 

Turnout Average: 6.5 

lb/hd-yr (Average flux 

of 207 μg/m2

-min) 

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Flux chamber sampling of ROG 

from open lots with analysis by 

GC/MS (Krauter, 2009)8

Average flux of 173 

μg/m2

-min from open 

lots 

Measured by GC/MS 

Evaluation

The recent California research that is available to quantify emissions from open 

corrals at dairies is from three studies conducted at dairies in the San Joaquin 

Valley. 

As mentioned above, Dr. Schmidt performed a study in 2005 using flux chambers 

and SCAQMD Method 25.3 to quantify emissions at two dairies located in 

Merced County and Kings County. Dr. Schmidt performed a follow-up study in 

2008 using flux chambers and SCAQMD Method 25.3 to quantify emissions at 

the same two dairies. However, the first study measured emissions only during 

the summer season while the 2008 study collected some samples during the 

winter season to characterize seasonal effects on the VOC emissions rates. The 

study results showed that winter VOC emissions rates from the corrals were 

lower than the summer rates. This information was used to adjust the summer 

data from the 2005 and 2008 studies to arrive at an annual average considering 

seasonal variability. The original study reports calculated emissions factors 

based on total head at the dairies. The measured flux and process surface areas 

for only the milk cow areas and estimated number of milk cows at the dairies in 

2005 and the reported number of milk cows at the dairies in 2008 were used to 

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calculate the VOC emissions factor based only on milk cows. This resulted in an 

annual VOC emissions factor of 6.6 lb/hd-yr for the corrals. 

Dr. Krauter’s study also measured VOC flux from six dairies in the San Joaquin 

Valley using flux chambers to collect samples. GC/MS was used to quantify VOC 

flux. Sampling occurred during the winter, early summer, and fall. The average 

flux values from this study can be compared to the flux values obtained in Dr. 

Schmidt’s study. This study resulted in average VOC flux values for the corrals 

that were similar but slightly less than the seasonal-adjusted averages from Dr. 

Schmidt’s 2005 and 2008 dairy studies. The study report states that emissions 

from the corrals were found to vary with surface temperature and season. Like 

Dr. Schmidt’s dairy studies, emissions from the corrals were found to be higher in 

the summer than the winter. As previously mentioned, the report contained an 

example of emissions that could be expected from a fictitious dairy based on the 

information gathered in the study. The fictitious dairy in the report had a VOC 

emission factor of 3.2 lb/hd-yr for the corrals, which is approximately half the 

annual average value from the Dr. Schmidt’s dairy study. 

Conclusion

The APCO has determined that the total VOC measurements from Dr. Schmidt’s 

2005 and 2008 studies provide the best available data to quantify VOC 

emissions from corrals at dairies. Dr. Krauter’s study resulted in similar average 

VOC flux rates from corrals but the study estimated a lower overall emissions 

rate for the fictitious dairy presented in the report. It appears that the dairy VOC 

compound profile used for the GC/MS captured a large portion of the mass of 

VOC emissions from corrals since the average flux measurements were similar 

to Dr. Schmidt’s study. Based on this, it appears that the corral area needed for 

the fictitious dairy was underestimated thereby resulting in lower VOC emissions. 

As stated above, it is more appropriate to base the emissions factor on the actual 

data from Dr. Schmidt’s study because the surface areas used to calculate the 

emissions factor in this report were based on the processes observed at the 

dairies studied rather than approximations based on a fictitious dairy. Therefore, 

the APCO proposes an emissions factor of 6.5 lb/hd-yr for the corrals. 

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Category 5: Lagoons, Storage Ponds, and Settling Basins 

Basis of Current VOC Emissions Factor 

Basis of the Current Dairy VOC Emissions Factor 

Previous Category 4: VOCs from lagoons and storage ponds

Process or 

Constituent 

Emissions Factor 

(lb/hd-yr) 

Basis for Current 

Emissions Factor 

Flux chambers with analysis by EPA TO-15, & 

EPA TO-11 (Schmidt, 2004)10 VOCs (except VFAs and Amines) from 

settling basins, 

lagoons, and storage 

ponds 

1.0 

Concentration analysis by EPA TO-15 and 

Emissions Modeling by ISCST3 (Krauter, 

2005)11

Dr. Schmidt measured VOC emissions from a dairy lagoon at one Merced 

County dairy using flux chambers in conjunction with EPA method TO-15 and 

EPA method TO-11. Dr. Krauter estimated VOC emissions from lagoons and 

storage ponds at two San Joaquin Valley dairies using TO-15 measurements of 

upwind and downwind concentrations in conjunction with atmospheric modeling 

techniques. 

Recent VOC Emissions Studies

Recent Studies – Lagoons, Storage Ponds, and Settling Basins 

New Studies 

Emissions Factors 

from New Studies Notes 

(lb/hd-yr) 

Flux chamber sampling of 

lagoons with analysis of Total 

ROG by SCAQMD 25.3 (Schmidt, 

2006)6

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 1.3 

Evaluation

Dr. Schmidt’s 2005 study used flux chambers to collect samples at two dairies 

located in Merced County and Kings County and SCAQMD Method 25.3 was 

used to quantify total VOC flux. The original study reports calculated emissions 

factors based on total head at the dairies. The measured flux, process surface 

areas, and estimated number of milk cows at the dairies in 2005 were used to 

calculate an emissions factor based only on milk cows. This resulted in an annual 

VOC emissions factor of 1.3 lb/hd-yr for the liquid manure handling system. 

 

11 Krauter, Charles, 2005. Concentration analysis by EPA TO-15 and Emissions Modeling by 

ISCST3 

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Conclusion

The District has determined that the VOC measurements taken by Dr. Krauter in 

2005 and the total VOC measurements from Dr. Schmidt’s 2005 study provide 

the best available data to quantify VOC emissions from dairy lagoons, storage 

ponds, and settling basins. Each of these studies resulted in a VOC emissions 

factor of 1.3 lb/hd-yr. Therefore, the APCO proposes an emissions factor of 1.3 

lb/hd-yr for the lagoons, storage ponds, and settling basins. Dr. Schmidt’s earlier 

2004 study reported lower emissions but only focused on a very limited number 

of compounds. SCAQMD Method 25.3, which was used in Dr. Schmidt’s later 

studies, is able to measure total VOCs and captures a greater proportion of the 

VOCs emitted at dairies, including volatile fatty acids and amines. All available 

studies indicated that VOC emissions from lagoons were relatively low; therefore, 

this source is not as significant as previously thought. 

Category 6: Liquid Manure Land Application 

Recent VOC Emissions Studies

Recent Studies – Liquid Manure Land Application 

New Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of 

lagoons with analysis of Total 

ROG by SCAQMD 25.3 (Schmidt, 

2009 – Phase IV)7

1.4 Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Evaluation

The only VOC emissions data that were available for liquid manure land 

application at a California dairy were from Dr. Schmidt’s Phase IV flux chamber 

study at a dairy located in Merced County. Total VOCs (as methane) were 

measured from the dry soil prior to land application and following application of 

liquid manure. VOC flux measurements from land application of chemical 

fertilizer at a different site were also performed for comparison purposes. 

Emissions were measured immediately after irrigation and at three hours, eight 

hours, and 21 hours after irrigation. The net VOC flux from liquid manure land 

application was found to be very low and was near the detection limits of the 

instrumentation. Therefore, the contribution of land application to VOC emissions 

at the dairy was primarily the result of the very large land application area (2,500 

acres) being irrigated with liquid manure three times per year. The land 

application area was shared with an adjacent dairy. The land application 

emissions factor given in the study report was based on the total number of milk 

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cows at both dairies and resulted in an annual VOC emissions factor of 1.4 lb/hdyr for liquid manure land application. 

 

Conclusion

The only California data available to calculate VOC emissions from liquid manure 

land application are from Dr. Schmidt’s Phase IV study; therefore, this data will 

be used to quantify VOC emissions from this source. Therefore, the APCO 

proposes an emissions factor of 1.4 lb/hd-yr for liquid manure land application. 

The study resulted in very low total VOC flux near the quantification limit. 

Additionally, there was an extremely low correlation for the estimated curve fit 

that was used to calculate overall emissions. Therefore, in future studies 

additional measurements are needed to better quantify the low net flux value to 

calculate emissions with greater accuracy. Because of the low flux value, the 

mass of emissions is primarily the result of the very large surface area for this 

process. Therefore, to more accurately assess VOC emissions from this source, 

more information needs to be gathered regarding the number of times liquid 

manure is applied to land, the number of acres irrigated for each event, and the 

total land application area at dairies in relation to the number of milk cows and 

total herd size. 

Category 7: Solid Manure Land Application 

Recent VOC Emissions Studies

Recent Studies – Solid Manure Land Application 

New Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of 

lagoons with analysis of Total 

ROG by SCAQMD 25.3 (Schmidt, 

2009- Phase IV)7

0.33 Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Evaluation

The only VOC emissions data that were located for solid manure land application 

at a California dairy were from Dr. Schmidt’s 2008 flux chamber study at a 

Merced County dairy. Total VOCs (as methane) were measured from the soil 

prior to land application of solid manure and following the application of solid 

manure. Initial emission measurements were performed for both incorporated 

and non-incorporated solid manure. However, no significant differences were 

found in the VOC emissions from incorporated non-incorporated solid manure. 

VOC emissions were measured for incorporated manure at one hour, three 

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hours, and 7 hours after application. The net VOC flux from solid manure land 

application was found to be very low and was near the detection limits of the 

instrumentation. The net VOC flux dropped back to background levels at 

approximately four hours after application. The contribution of solid manure land 

application to VOC emissions at the dairy was the result of solid manure being 

applied to the very large application area (2,500 acres) twice per year. The 

annual VOC emissions factor from the study for solid manure land application 

based only on milk cows was 0.33 lb/hd-yr. 

 

Conclusion

The only California data that is available to calculate VOC emissions from solid 

manure land application are from Dr. Schmidt’s Phase IV study; therefore, the 

data in that study will be used to quantify VOC emissions from this source. 

Therefore, the APCO proposes an emissions factor of 0.33 lb/hd-yr for solid 

manure land application. 

The study resulted in very low total VOC flux near the quantification limit and the 

mass of emissions is primarily the result of the very large surface area for this 

process. To more accurately assess VOC emissions from this source, more 

information needs to be gathered regarding the number of times solid manure is 

applied to land and the total land application area at dairies in relation to the 

number of milk cows and total herd size. 

Category 8: Separated Solids 

Recent VOC Emissions Studies

Recent Studies – Separated Solids (fresh and aged) 

New Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of 

lagoons with analysis of Total 

ROG by SCAQMD 25.3 (Schmidt, 

2006 - Phase III6

) 

0.06 Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Evaluation

The only California data available to calculate VOC emissions from separated 

solids are from Dr. Schmidt’s 2005 study. Flux chambers were used measure 

emissions at a dairy located in Merced County and SCAQMD Method 25.3 was 

used to quantify total VOC flux. Dr. Schmidt also measured this source in 2004 

using TO-15 to quantify emissions. The total VOC emissions measured using 

SCAQMD Method 25.3 were approximately twice the emissions measured using 

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TO-15. But the overall emissions quantified with either method were very low, 

possibly because of the high solubility of the volatile compounds emitted from 

dairies. The annual VOC emissions factor for separated solids resulting from the 

2005 study using SCAQMD Method 25.3 adjusted for only milk cows is 0.06 

lb/hd-yr. 

Conclusion

The APCO has determined that the total VOC measurements from Dr. Schmidt’s 

Phase III study provide the best available data to quantify VOC emissions from 

separated solids. All available studies indicate that VOC emissions from 

separated solids are very low. However, the earlier 2005 study used only TO-15 

and focused on a very limited number of compounds. SCAQMD Method 25.3, 

which was used in Dr. Schmidt’s later studies, captures a more complete range 

of compounds, including volatile fatty acids and amines. Therefore, the APCO 

proposes an emissions factor of 0.06 lb/hd-yr for solid manure separated solids. 

Given the very low emissions measured, future dairy emission studies do not 

need to focus on this source. 

Category 9: Solid Manure Storage 

Recent VOC Emissions Studies

Recent Studies – Solids Storage 

New Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of 

lagoons with analysis of Total 

ROG by SCAQMD 25.3 (Schmidt, 

2006 – Phase III6

) 

0.15 Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Evaluation

The only recent California data that is available to calculate VOC emissions from 

stored solids are from Dr. Chuck Schmidt’s 2005 study. Flux chambers were 

used to measure emissions at a dairy located at two dairies located in Merced 

County and Kings County. The annual VOC emissions factor from the study for 

solid manure land application adjusted for only milk cows is 0.15 lb/hd-yr. 

 

Conclusion

The only California data that available to calculate VOC emissions from 

separated solids are from Dr. Schmidt’s 2005 study; therefore, the data from this 

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study will be used to quantify VOC emissions from this source. Therefore, the 

APCO proposes an emissions factor of 0.15 lb/hd-yr for solid manure storage. 

Category 10: Silage Piles 

 

Recent VOC Emissions Studies

Recent Studies –Silage Piles 

New Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of corrals 

with analysis of Total ROG by 

SCAQMD 25.3 (Schmidt, 2006 – 

Phase III6

) 

Silage Pile Average 

Flux: 29,335 μg/m2

-min 

(4.4 lb/hd-yr) 

Seasonally and Time 

Adjusted Average Flux 

based on 2008 Study: 

21,435 μg/m2

-min 

(3.2 lb/hd-yr) 

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Flux chamber sampling of corrals 

during summer and winter 

seasons with analysis of Total 

ROG by SCAQMD 25.3 

(Schmidt, 2009 – Phase IV7

) 

Seasonally and Time 

Adjusted Average Flux: 

39,405 μg/m2

-min 

(9.7 lb/hd-yr) 

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Highest measured flux from freshly disturbed 

silage: 85,240 μg/m2

 and 81,374 μg/m2 

 

Although higher average flux was measured 

in 2008, the higher per head emission factor is 

also due to an additional silage pile being 

open at each dairy during the Phase IV study. 

Flux chamber sampling of ROG 

from open lots with analysis by 

GC/MS (Krauter, 20098

) 

Average flux of 19,170 

μg/m2

-min for disturbed 

silage and 4,229 

μg/m2

-min undisturbed 

silage 

Measured by GC/MS 

Time dependent data not provided but highest 

measured flux from freshly disturbed silage 

(75,977 μg/m2

 and 72,698 μg/m2) is very 

similar to highest flux measured in Schmidt 

Phase IV study. 

Evaluation

The recent California research that is available to quantify emissions from silage 

piles at dairies is based on three studies conducted at dairies in the San Joaquin 

Valley. 

Dr. Schmidt’s Phase III study used flux chambers and SCAQMD Method 25.3 to 

quantify emissions at two dairies located in Merced County and Kings County. As 

previously mentioned, Dr. Schmidt performed a follow-up study in 2008 (Phase 

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IV) using flux chambers to quantify emissions at the same two dairies. In the 

Phase IV study, some samples were collected during the winter season to 

characterize seasonal effects on the VOC emissions rates. The study showed 

that winter VOC emissions rates from the feed sources were lower than the 

summer rates. This information was used to adjust the summer data from the 

Phase III and Phase IV studies to arrive at an annual average considering 

seasonal variability. Additionally, measurements were taken at one of the dairies 

throughout the day to characterize how emissions changed with time. The VOC 

emissions from the silage piles were the highest when the silage was initially 

disturbed to remove feed for the TMR but declined with time. The silage that had 

not been disturbed had much lower emissions. The operational practices 

observed at the dairy were used to simulate emissions and arrive at an average 

annual VOC emissions factor. The adjustment factors from the Phase IV study 

were also used to adjust the emissions measurements from the Phase III study. 

The following average flux values were derived from these studies: corn silage: 

34,681 μg/m2

-min; alfalfa silage: 17,458 μg/m2-min; and wheat silage: 43,844 

μg/m2-min. 

For reference purposes, the measured flux and process surface areas for the 

open faces of the silage piles can also be used to calculate the seasonally 

adjusted VOC emissions factor based on the number of milk cows at the dairies. 

This would result in an average VOC emissions factor of 6.5 lb/hd-yr for the 

uncovered faces of the silage piles. However, the lb/hd-yr emissions factor may 

slightly overestimate VOC emissions from silage since the silage piles at the 

Merced dairy also served other dairies with additional milk cows that were not 

counted when determining this value. Additionally, because emissions from this 

source are more dependent on the exposed area of the silage piles than the 

number of cows at the dairy, using the average flux values to calculate VOC 

emissions is more appropriate for this source. This is illustrated by the fact that a 

significant portion of the increased emissions found in the Phase IV study as 

compared to the Phase III study can be attributed to an additional silage pile 

being open and utilized at each dairy during the Phase IV study. 

Dr. Krauter’s study also used flux chambers to measure VOC emissions at the 

silage piles at six dairies in the San Joaquin Valley. GC/MS was used to quantify 

VOC flux. Sampling occurred during the winter, early summer, and fall but no 

seasonal effects were found for VOC emissions from feed sources. The flux 

values from this study can be compared to the flux values obtained in Dr. 

Schmidt’s study. This study resulted in maximum VOC flux values for the 

disturbed silage that were very comparable to the maximum VOC flux values 

from Dr. Schmidt’s Phase IV dairy studies. However, the average VOC flux 

values for the silage piles were significantly less than the seasonal-adjusted 

averages from Dr. Schmidt’s Phase III and Phase IV dairy studies. The reason 

for this difference is not known at this time. There was a great deal of variability 

in the flux measured from the silage at the dairies. The variability may be related 

to time of the measurements taken after initial disturbance, types of silage used, 

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or silage compaction; however, the current study report does not provide this 

information but states that an upcoming report may contain at least some of this 

information. It must be noted that Dr. Krauter’s study also used INNOVA 

analyzers to quantify alcohol emissions measurements from sources at the dairy. 

The INNOVA analyzer measurements were taken at the same source within 10 

minutes of the canister samples analyzed with GC/MS but resulted in much more 

alcohol emissions that were three to four times the values obtained with the 

canister samples. Feed is not a significant source of ammonia emissions so 

ammonia interference does not account for this difference. The project report 

states that Dr. Donald Blake at UC Irvine and other project collaborators have 

questioned the ability of the GC-MS system to extract all of the water soluble 

gasses, such as alcohols, from the canisters when they are analyzed, so the 

higher values may be more accurate. Additional information and research is 

needed to determine which of the values from Dr. Krauter’s study are more 

representative of emissions from silage piles. 

Conclusion

The APCO has determined that the total VOC flux measurements from Dr. 

Schmidt’s Phase III and Phase IV studies provide the best available data to 

quantify VOC emissions from silage piles at dairies. Because emissions from this 

source are more directly related to the exposed area of the silage piles, the 

measured flux will be used to calculate emissions on a per area basis rather than 

a per cow basis. The APCO proposes that the following average flux values be 

used to calculate emissions from the silage piles at a dairy on a per area basis: 

corn silage: 34,681 μg/m2-min; alfalfa silage: 17,458 μg/m2-min; and wheat 

silage: 43,844 μg/m2-min. 

Dr. Krauter’s study resulted in very similar maximum VOC flux rates but lower 

average VOC flux using canister samples and GC/MS. Insufficient information 

was provided to determine if this difference in the measured values was timedependent, related to the types of silage used, or resulted from other factors. The 

currebt report states that some of this information may be provided in a 

forthcoming report. Dr. Krauter’s study also resulted in higher average VOC flux 

rates using INNOVA analyzers. At this time it is not known which of the values 

obtained by GC/MS or the INNOVA analyzer better represent the actual VOC 

emissions from silage during the study period. Therefore, additional studies are 

needed to compare different sample collection and analyses techniques for 

measuring emissions from feed sources. Dr. Schmidt’s Phase IV study found 

seasonal variation that was not found in Dr. Krauter’s study but the winter data 

set from Dr. Schmidt’s Phase IV study was very limited. Therefore, additional 

data also needs to be collected in the winter and/or fall seasons to better quantify 

seasonal variability of VOC emissions from this source. 

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Category 11: Total Mixed Ration (Bunker Feed) 

 

Recent VOC Emissions Studies

Recent Studies – Total Mixed Ration (TMR) (feed placed in front of cows) 

New Studies 

Emissions Factors 

from New Studies 

(lb/hd-yr) 

Notes 

Flux chamber sampling of corrals 

with analysis of Total ROG by 

SCAQMD 25.3 (Schmidt, 2006 – 

Phase III6

) 

TMR Average Flux: 

40,061 μg/m2

-min 

(38.2 lb/hd-yr) 

Seasonally and Time 

Adjusted Average Flux 

based on 2008 Study: 

15,415 μg/m2

-min 

(13.6 lb/hd-yr) 

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Flux chamber sampling of corrals 

during summer and winter 

seasons with analysis of Total 

ROG by SCAQMD 25.3 

(Schmidt, 2009 – Phase IV7

) 

Seasonally and Time 

Adjusted Average Flux: 

10,696 μg/m2

-min 

(10.0 lb/hd-yr) 

Total VOC (including VFAs and amines) as 

methane measured by SCAQMD 25.3 

Flux chamber sampling of ROG 

from TMR with analysis by 

GC/MS (Krauter, 20098

) 

Average flux of 8,260 

μg/m2

-min for TMR Measured by GC/MS 

Evaluation

The recent California research that is available to quantify emissions from Total 

Mixed Ration (TMR) at dairies is based on three studies conducted at dairies in 

the San Joaquin Valley. 

Dr. Schmidt’s Phase III study used flux chambers and SCAQMD Method 25.3 to 

quantify emissions at two dairies located in Merced County and Kings County 

and a follow-up study, Phase IV used the same methodologies but with a focus 

on seasonal and temporal variability. The VOC emissions from the TMR, the feed 

placed to be consumed by the cows, were the highest when the feed was first 

placed but declined with time. The TMR was the largest source of VOC 

emissions at the dairies and also had the most variability. The maximum flux 

measured from the TMR at the Kings County dairy was significantly higher than 

the flux measured from the TMR at the Merced County dairy. The operational 

practices observed at the dairies were used to simulate emissions and arrive at 

an average annual VOC emissions factor. However, the original exponential 

curve fit used in the report to calculate VOC emissions from the milk cow TMR 

had a very low correlation value - so low that it could be argued that there was no 

true correlation between the data set and the exponential equation used. 

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Therefore, the emissions factor for the TMR used in this report is based on a 

slightly more conservative linear curve fit of the 2008 data set that had a higher 

correlation value. The adjustment factors derived from the 2008 study were also 

used to adjust the emissions measurements from the 2005 study for both 

temporal and seasonal variability. As with silage, the other feed emissions 

source, it has been determined that using the average flux value and the area of 

the TMR placed for the cows to calculate VOC emissions is more appropriate for 

this source. The following average flux value derived these studies can be used 

to calculate emissions from the TMR on a per area basis: 13,056 μg/m2-min. For 

reference purposes, the measured flux and process surface areas for the TMR 

can also be used to calculate the seasonally adjusted VOC emissions factor 

based on the number of milk cows at the dairies, which results in an average 

VOC emissions factor of 11.8 lb/hd-yr for the TMR. 

 

Dr. Charles Krauter’s study (2009) also used flux chambers to measure VOC 

emissions at the silage piles at six dairies in the San Joaquin Valley. Sampling 

occurred during the winter, early summer, and fall. No seasonal effects were 

found for VOC emissions from feed sources. However, like in Dr. Schmidt’s 

study, emissions from the TMR were found to decrease with time after placement 

of the feed. The average flux values from this study can be compared to the flux 

values obtained in Dr. Schmidt’s study. This study resulted in average VOC flux 

values for the TMR that were less than the seasonally adjusted averages from 

Dr. Schmidt’s Phase III and Phase IV dairy studies. The study also resulted in 

lower emissions from the TMR for the fictitious dairy described in the report. As 

with the silage measurements, the INNOVA analyzer measurements resulted in 

much higher alcohol emissions than the canister samples analyzed by GC/MS. 

More data were collected on TMR emissions at two of the dairies but these data 

were not presented in the current project report. The report states that these data 

will be presented in a forthcoming report. These additional data may be useful in 

explaining some of the variability. 

Conclusion

The APCO has determined that the total VOC measurements from Dr. Schmidt’s 

Phase III and Phase IV studies provide the best available data to quantify VOC 

emissions from feed bunkers at dairies. Therefore, the APCO proposes that the 

following average flux value be used to calculate emissions from the TMR on a 

per area basis: 13,056 μg/m2-min. 

Dr. Krauter’s study resulted in slightly lower average VOC flux using canister 

samples and GC/MS. However, VOC flux rates measured using INNOVA 

analyzers were higher and may be similar to the measurements in Dr. Schmidt’s 

study if the decrease in emissions after placement is considered. However, the 

report does not contain sufficient data on the INNOVA measurements to make a 

determination at this time. The information in the forthcoming report for a related 

project may be useful in this determination. Additional studies are also needed to 

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compare different sample collection and analyses techniques for measuring 

emissions from feed sources. Additional data also needs to be collected in the 

winter and/or fall seasons to better quantify seasonal variability of VOC 

emissions from this source. Additionally, the correlations for the curve fits that 

were examined to calculate emissions from TMR based on data from the Phase 

IV Schmidt Study were all low. Therefore, in future studies additional 

measurements are needed to better characterize changes in emissions over 

time. 

Category 12: Composting 

 

Composting 

Process or 

Constituent 

Current Emissions 

Factor 

(lb/hd-yr) 

Basis for Current 

Emissions Factor 

Composting TBD, >0 N/A 

Although unknown quantities of VOCs may be emitted during composting of dairy 

manure solids, no California emissions data could be located that were 

representative of this source. Therefore, the APCO will consider the emissions 

from this source to be of the category to be determined but greater than zero. 

The APCO recommends for further research to quantify emissions from this 

source. 

Summary of Dairy Emissions 

In summary, the table below shows the APCO recommended emission factor for 

each source and constituent: 

Per Cow Dairy Emissions Factor 

Process or Constituent Emissions (lb/hd-yr) 

1. Enteric Emissions from Cows 4.1 

2. Milking Parlor(s) 0.03 

3. Freestall Barns 1.8 

4. Corrals/Pens 6.6 

5. Liquid Manure Handling 

(Lagoons, Storage Ponds, 

Basins) 

1.3 

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Per Cow Dairy Emissions Factor 

Process or Constituent Emissions (lb/hd-yr) 

6. Liquid Manure Land 

Application 1.4 

7. Solid Manure Land Application 0.33 

8. Separated Solids Piles 0.06 

9. Solid Manure Storage 0.15 

12. Composting & Manure 

Disturbance TBD, >0

Total not including Feed 15.8

Silage Pile VOC Emissions Flux 

10. Silage Piles Emissions Flux (μg/m2

-min) 

1. Corn Silage 34,681

2. Alfalfa Silage 17,458

3. Wheat silage 43,844

Average TMR VOC Emissions Flux 

11. TMR Emissions Flux (μg/m2

-min) 

Average 13,056 

 Summary of Future Research Recommendations

The APCO believes that future research will continue to improve the quality of 

dairy emissions factors and recommends future research on the following items: 

• Additional data are needed on different process emissions and effects of 

management practices on emissions. 

• Additional data are needed to better assess temporal and seasonal 

variability of emissions sources at dairies, particularly feed sources 

• Additional information needs to be gathered regarding total land 

application area in relation to the number of milk cows and/or total head at 

a dairy and the frequency of land application of solid and liquid manure 

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• Additional data are needed comparing the effects of different sample 

collection techniques (e.g. flux chambers and wind tunnels) on calculated 

emissions rates 

• Further information is needed to compare real-time emission 

measurement techniques, such as the INNOVA analyzer, and total VOC 

and canister methods 

• Standardized methods and a target suite of compounds are needed to 

guide future research work regarding dairy emissions. Specific research 

should be undertaken to determine which gases should be included from 

amines, oxygenated VOCs, VFAs, phenols, and other potentially important 

compounds, as well as to develop improved sampling, analytical and 

quantification methods. 

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Appendix A - List of Dairy Emissions Studies Reviewed 

Previous Studies Reviewed to Establish the 2005 Dairy VOC Emissions 

Factor

Carbonyl Emission Factors by DNPH: Cassel, Flocchini, Green, Higashi (2005). 

On-Farm Measurements of Methane and Select Carbonyl Emission Factors for 

Dairy Cattle (ftp://ftp.arb.ca.gov/carbis/ag/agadvisory/cassel05jan26.pdf) 

Non-methane VOCs emitted from slurry manure in an enclosed chamber 

measured using adsorbent material and thermal desorption GC/MS: Hobbs, 

Webb, Mottram, Grant, Misselbrook (2004). Emissions of Volatile Organic 

Compounds Originating from UK Livestock Agriculture. 2004©. Society of 

Chemical Industry. J Sci Food Agric 84:1414-1420 

(http://www.valleyair.org/busind/pto/dpag/VOC_from_UK_livestock.pdf) 

VFAs by sorbent tubes and analyzed on a thermal desorption TDS/GC-MS 

system: Koziel (May 2006). Measurement of airborne volatile fatty acids emitted 

from dairy cows and their waste using sorbent tubes sampling and thermal 

desorption/GC-MS analysis 

(http://www.valleyair.org/busind/pto/dpag/Appendices/Appendix%2024%20%20P

lan%20of%20work%20VFAs_FMM.pdf)

VOC Concentration by EPA Method TO-15; Speciation by GC-MS; Emission 

Modeling by IST-STv3: Krauter, Goorahoo, Goodrich, Beene (2005). Monitoring 

and Modeling of ROG at California Dairies,

(ftp://ftp.arb.ca.gov/carbis/ag/agadvisory/krauter05jan26.pdf) 

(http://www.valleyair.org/busind/pto/dpag/krauter_epa_april_5.pdf) 

 

VFAs (acetic, propionic, butyric, isobutyric, isovaleric, valeric, and caproic acids), 

cresols, phenol, indole, and skatole from beef feedlots by sorbent tubes and GC: 

McGinn, Janzen, Coates (2003). Atmospheric Ammonia, Volatile Fatty Acids, 

and Other Odorants near Beef Feedlots

Cows in an environmental chamber oxygenated VOCs (i.e. Ketones, Aldehydes, 

Alcohols, Carbonyls, Phenols, and Volatile Fatty Acids (VFAs)) by PTR/MS; TO15 VOCs by GC/MS; total non-methane, non-ethane organic compounds by GCFID; VFAs by GC-MS thermo-desorption: Mitloehner (2005). Volatile Organic 

Compound Emissions from Dairy Cows and Their Excreta

(ftp://ftp.arb.ca.gov/carbis/ag/agadvisory/mitloehner05jan26.pdf) 

EPA Flux Chambers with VOCs by EPA Method TO-15 (GC/MS); Amines by 

NIOSH 2010 (GC/IC); Aldehydes & Ketones by EPA Method TO-11 (GC/HPLC); 

Volatile Organic Acids by EAS Method (UV-VIS): Schmidt, Card, Gaffney (2005). 

Assessment of Reactive Organic Gases and Amines from a Northern California 

Dairy Using the USEPA Surface Emission Isolation Flux Chamber

(ftp://ftp.arb.ca.gov/carbis/ag/agadvisory/schmidt05jan26.pdf) Process units 

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DRAFT DAIRY EMISSIONS FACTOR REPORT 

measured: Flush lanes; Solids storage piles; Lagoon (inlet and outlet of lagoon); 

Solids in Solids separator; Bedding in pile for freestall; Freestall area; Barn 

turnout and corral area; Manure piles in turnout; Heifer pens (dry cow area); 

Open feed storage in barn feed lanes; and Milk parlor wastewater effluent stream 

Rabaud, N.E. Ebeler, S.E., Asbaugh, L.L, and R.G. Flocchini. 2002©. The 

application of Thermal Desorption GC/MS with Simultaneous Olfactory 

Evaluation for the Characterization and Quantification of Odor Compounds from 

a Dairy. Crocker Nuclear laboratory and department of Viticulture and Enology. 

American Chemical Society, 10.1021/jf020204u 

Ngwabie, N.M. and T. Hintz. 2005©. Mixing Ratio Measurements and Flux 

Estimates of Volatile Organic Compounds (VOC) from a Cowshed with 

Conventional Manure Treatment Indicate Significant Emissions to the 

Atmosphere. Geographical Research Abstracts, Vol. 7, 01175, 2005 Sref-ID: 

1607-7962/gra/EGU05-A-01175 

Koziel, J.A., Spinhirne, J.P., and Back, B.H. Measurements of Volatile Fatty 

Acids Flux from Cattle Pens in Texas. Texas Agricultural Experiment Station, 

Texas A&M University. Paper #04-A-646-AWMA 

Additional VOC Studies/Papers Reviewed

SJVAPCD 2008 Dairy Emissions Study (August 2009) – Summary of Dairy 

Emission Estimation Procedures, Prepared by Thomas Card and Dr. Charles 

Schmidt 

California Air Resource Board (ARB) Dairy Operations: An Evaluation and 

Comparison of Baseline and Potential Mitigation Practices for Emissions 

Reductions In the San Joaquin Valley (May 01, 2009), Principal Investigator: Dr. 

Charles Krauter (http://www.arb.ca.gov/research/apr/past/04-343.pdf) 

Phillip Alanis, Mark Sorenson, Matt Beene, Charles Krauter, Brian Shamp, Alam 

S. Hasson. “Measurement of non-enteric emission fluxes of volatile fatty acids 

from a California dairy by solid phase micro-extraction with gas 

chromatography/mass spectrometry”, Atmospheric Environment 42 (2008) 6417–

6424 

Huawei Sun, Steven L. Trabue, Kenwood Scoggin, Wendi A. Jackson, Yuee 

Pan, Yongjing Zhao, Irina L. Malkina, Jacek A. Koziel, and Frank M. Mitloehner. 

“Alcohol, Volatile Fatty Acid, Phenol, and Methane Emissions from Dairy Cows 

and Fresh Manure.” Journal of Environmental Quality (37:615–622), Volume 37, 

March–April 2008. 

Stephanie L. Shaw , Frank M. Mitloehner, Wendi A. Jackson, Edward J. 

DePeters, James G. Fadel, Peter H. Robinson, Rupert Holzinger, Allen H. 

Goldstein. “Volatile Organic Compound Emissions from Dairy Cows and Their 

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Waste as Measured by Proton Transfer-Reaction Mass Spectrometry”, 

Environmental Science and Technology. VOL. 41, NO. 4, 2007

California Air Resource Board (ARB) Volatile Fatty Acids, Amine, Phenol, and 

Alcohol Emissions from Dairy Cows and Fresh Waste (May 31, 2006), Frank 

Mitloehner, Ph.D 

(http://www.arb.ca.gov/ag/caf/MitloehnerDairyChamberEmissions2006.pdf) 

California Air Resource Board (ARB) Dairy Air Emissions Report (May 2006) – 

Summary of Dairy Emission Estimation Procedures, Prepared by Thomas Card 

and Dr. Charles Schmidt 

(http://www.arb.ca.gov/ag/caf/SchmidtDairyEmissions2005.pdf) 

Huawei Sun, Yuee Pan, Yongjing Zhao, Wendi A. Jackson, Lisa M. Nuckles, 

Irina L. Malkina, Veronica E. Arteaga and Frank M. Mitloehner. “Effects of 

Sodium Bisulfate on Alcohol, Amine, and Ammonia Emissions from Dairy Slurry”, 

Journal of Environmental Quality 37:608-614. February 20, 2008 

Jenny Filipy, Brian Rumburg, George Mount, Hal Westberg, Brian Lamb. 

“Identification and quantification of volatile organic compounds from a dairy”, 

Atmospheric Environment 40 (2006) 1480–1494

Koziel, Jacek A., Spinhirne, Jarett P., and Lloyd, Jenny D. - Texas Agricultural 

Experiment Station, Texas A&M University, Amarillo, TX; Parker, David B. - West 

Texas A&M University, Killgore Research Center, Canyon, TX; Wright, Donald 

W. and Kuhrt, Fred W. - Microanalytics, Round Rock, TX. “Evaluation of Sample 

Recovery of Malodorous Livestock Gases from Air Sampling Bags, Solid-Phase 

Microextraction Fibers, Tenax TA Sorbent Tubes, and Sampling Canisters”. 

Journal of the Air & Waste Management Association, Volume. 55:1147–1157. 

August 2005. 

Richard, Tom L. and Wheeler, Eileen, Penn State University - Department of 

Agricultural and Biological Engineering; Varga, Gabriella, Penn State University - 

Department of Dairy and Animal Science; Kaye, Jason; and Ann Bruns, Mary, 

Penn State University - Department of Crop and Soil Science, 2005 Penn State 

Dairy Cattle Nutrition Workshop. Strategies for Reducing Gas Emissions from 

Dairy Farms. (2005) 

Parker, David B., Caraway, Edward A., Rhoades, Marty B., Donnell, Chanci, and 

Spears, Jan – West Texas A&M University, Canyon, TX; Cole, N. Andy and 

Todd, Richard - USDA-ARS, Bushland, TX; Casey, Kenneth D. - Texas AgriLife 

Research, Amarillo, Texas. “Effect of Wind Tunnel Air Velocity on VOC Flux 

Rates from CAFO Manure and Wastewater”. ASABE Meeting Presentation 

Paper # 08-3897 for presentation at the 2008 ASABE Annual International 

Meeting at Providence, Rhode Island, June 29 – July 2, 2008 

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Caraway, Edward A., Parker, David B., Olsen, Mark J., Donnell, Chanci, 

Rhoades, Marty B., and Spears, Jan – West Texas A&M University, Canyon, TX; 

Casey, Kenneth D. - Texas AgriLife Extension, Amarillo, Texas. “Diel VOC 

Emissions from a Beef Cattle Feedyard”. ASABE Meeting Presentation Paper # 

084136 for presentation at the 2008 ASABE Annual International Meeting at 

Providence, Rhode Island, June 29 – July 2, 2008 

Hudson, N. and Ayoko, G.A. - International Laboratory for Air Quality and Health, 

School of Physical and Chemical Sciences, Queensland University of 

Technology. “Comparison of emission rate values for odour and odorous 

chemicals derived from two sampling devices”. Journal of Atmospheric 

Environment 10:1016. March 23, 2009. 

Hudson, N., Ayoko, G.A., Dunlop, M., Duperouzel D., Burrell D., Bell, K., 

Gallagher E., Nicholas, P., and Heinrich, N. 2009. “Comparison of Odour 

Emission Rates Measured from Various Sources using two Sampling Devices”. 

Bioresource Technology 100:118-124. 

Hudson, N. and Ayoko, G.A. - International Laboratory for Air Quality and Health, 

School of Physical and Chemical Sciences, Queensland University of 

Technology. “Odour sampling 1: Physical chemistry considerations”. Journal of 

Bioresource Technology 99 (2008) 3982–3992. June 26, 2007. 

Hudson, N. and Ayoko, G.A. - International Laboratory for Air Quality and Health, 

School of Physical and Chemical Sciences, Queensland University of 

Technology. “Odour sampling. 2. Comparison of physical and aerodynamic 

characteristics of sampling devices: A review”. Journal of Bioresource 

Technology 99 (2008) 3993–4007. May 23, 2007. 

Rhoades, Marty B., Parker, David B., Perscbacher-Buser, Zena, and DeOtte, 

Robert E. – West Texas A&M University, Canyon, TX; Auvermann, Brent W. - 

Texas AgriLife Extension, Amarillo, TX; Cole, N. Andy - USDA-ARS, Bushland, 

TX. “Factors Affecting Emission Measurements with Surface Isolation Flux 

Chambers”. ASAE Meeting Presentation Paper # 054026 for presentation at the 

2005 ASAE Annual International Meeting at Tampa, Florida, July 17 – 20, 2005 

Appendix H October 21, 2010

H-40

 Final Draft Staff Report With Appendices For

Revised Proposed Amendments to Rule 4570