Peer-Reviewed Report
Updating Ozone Calculations and
Emissions Profiles for use in the
Atmospheric and Health Effects
Framework Model
Stratospheric Protection Division
Office of Air and Radiation
U.S. Environmental Protection Agency
Washington, D.C. 20460
February 27, 2015
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Preface
This report was prepared by the U.S. Environmental Protection Agency (EPA] with the support of its
contractor, ICF International. Key contributors included Melissa Fiffer and Robert Landolfi from the EPA,
Dr. Rawlings Miller, Jessica Kyle, and Mark Wagner from ICF, and Dr. Sasha Madronich from the National
Center for Atmospheric Research (NCAR], This report describes updates to the EPA's Atmospheric and
Health Effects Framework (AHEF], which models adverse human health effects associated with a
depleted stratospheric ozone layer. The AHEF is updated regularly to reflect new information and
science. The updates presented in this report incorporate new values for ODS characteristics and an
updated global emissions profile. Because these updates are specific to one AHEF module, this report
does not attempt to comprehensively describe the data and methodology behind the AHEF. For a fuller
description of the AHEF methodology, please see prior peer-reviewed EPA reports Human Health
Benefits of Stratospheric Ozone Protection (2006]1 and Protecting the Ozone Layer Protects Eyesight: A
Reporton Cataract Incidence in the United States Using the AHEF Model (2010],2
The initial report was drafted in 2012. In 2013, the draft final report was peer reviewed for its technical
content by Dr. Stephen Montzka of the National Oceanic and Atmospheric Administration, and
subsequently by Dr. Robyn Lucas of the National Centre for Epidemiology & Population Health at
Australian National University. The peer reviewers were asked to draw upon their expertise in ozone
depleting substance emissions and ultraviolet radiation health modeling and science to comment on
whether the data inputs, approach, and methodologies presented in the report reflect sound scientific
and analytical practice, and adequately address the questions at hand.
Written comments were received from the peer reviewers. Comments and data received were used to
adjust the draft methodology to rely on the global ODS emissions profiles from the World Meteorological
Organization's (WMO] Scientific Assessment of Ozone Depletion: 2010 (WMO 2011], which represented
the most up-to-date understanding of ozone depletion at the time the report was being finalized (mid-
2013], A number of comments also identified areas for technical clarification and opportunities for
future improvements. Given the extent of changes made in response to comments received, the revised
report was re-reviewed by Dr. Stephen Montzka and Dr. Michael Kurylo of the National Aeronautics and
Space Administration in late 2014 and early 2015. All comments of the reviewers were considered, and
the document was modified accordingly.
The EPA wishes to acknowledge everyone involved in the development of this report and to thank the
peer reviewers for their time, effort, and expert guidance. The involvement of the peer reviewers greatly
enhanced the technical soundness of this report. The EPA accepts responsibility for all information
presented and any errors contained in this document.
Stratospheric Protection Division
Office of Atmospheric Programs
U.S. Environmental Protection Agency
Washington, DC 20460
1 http: //www, ei3a.gov/ozone/science/effects/AH EFApr2 006.pdf
2 http://www.epa.gov/ozone/science/effects/AHEFCataractReport.pdf
i
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AFEAS
Alternative Fluorocarbons Environmental Acceptability Study
AGAGE
Advanced Global Atmospheric Gases Experiment
AHEF
Atmospheric and Health Effects Framework
BAF
Biological amplification factor
BCC
Basal cell carcinoma
CFC
Chlorofluorocarbon
CCM
Chemistry-climate models
CMM
Cutaneous malignant melanoma
DU
Dobson units
EESC
Equivalent effective stratospheric chlorine
HCFC
Hydrochlorofluorocarbon
IPCC
Intergovernmental Panel on Climate Change
MP
Montreal Protocol
NASA
National Aeronautics and Space Administration
NCI
National Cancer Institute
NHANES
National Health and Nutrition Examination Study
NMSC
Non-melanoma skin cancer
NOAA
National Oceanic and Atmospheric Administration
ODS
Ozone-depleting substance
ppb
Parts per billion
ppt
Parts per trillion
QBO
Quasi-biennial oscillation
ROW
Rest of world
see
Squamous cell carcinoma
SEER
Surveillance, Epidemiology, and End Results Program
SRES
Special Report Emissions Scenarios
TEAP
Technology and Economic Assessment Panel
TOMS
Total Ozone Mapping Spectrometer
UNEP
United Nations Environment Program
USGCRP
U.S. Global Change Research Program
UV
Ultraviolet
VM
EPA's Vintaging Model
WMO
World Meteorological Organization
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Table of Contents
Preface i
Acronyms ii
Table of Contents iii
Chapter 1: Introduction 1
Chapter 2: Updating ODS Emission Profiles 3
Selection of a New Global Emissions Profile 4
Comparison of ODS Emissions Profiles 5
Chapter 3: Updates to AHEF Ozone Calculations 8
Updates to EESC Inputs and Impacts on Model Estimation 8
Updates to Ozone Calculations and Impacts on Model Estimation 11
Chapter 4: Results of Updates 14
Comparison of EESC 14
Comparison of Ozone 18
Comparison of Health Benefits 19
Chapter 5: Future Modeling and Research 21
Emissions Profiles for Future ODS Control Policy Scenarios 21
Future AHEF Updates 22
References 23
Appendix A: Potential Global ODS and ODS Substitute Data Sources 25
Appendix B: Emission Profile Estimates from 1950 through 2100 26
Appendix C: Comparison of Emission Profiles by Species 27
Appendix D: Parameters and Coefficients Used to Inform the EESC and Ozone Calculations 30
Appendix E: Total Column Ozone for Modeled Policy Scenarios 32
Appendix F: Explanation of Differences between VM1999 and VM2012 33
iii
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Chapter 1: INTRODUCTION
The Atmospheric and Health Effects Framework (AHEF] was created in the mid-1980s to assess the
adverse human health effects associated with a depleted stratospheric ozone layer. Historically, the
AHEF has estimated the probable increases in skin cancer mortality, skin cancer incidence, and
cataract incidence in the United States that result from ozone-depleting substance (ODS] emission
scenarios relative to a 1979-1980 baseline (i.e., prior to significant ozone depletion]. This baseline is
defined as the health effects that would have occurred if the ozone concentrations that existed in
1979-1980 had been maintained through the time period modeled. The AHEF has also been
historically used to evaluate the U.S. health benefits associated with progressively stronger ozone layer
protection policies under the Montreal Protocol on Substances that Deplete the Ozone Layer and its
associated amendments and adjustments.
The AHEF consists of a series of independent modules (e.g., emissions, ozone projections, ultraviolet
exposure, and health effects modules] that estimate U.S. health benefits related to reductions in ODS
emissions. Figure 1 presents an overview of the modules within the AHEF.
Figure 1: Overview of the AHEF Modules
Consumption of ODS
Market growth rates
TOMS satellite data
Historical ozone concentrations &
ODS emissions estimates
Project Ozone Depletion
(Vintaging and UIUCModules)
2005 Census Bureau Population
projected population rates
Project Population
Action spectrum
T
Historical data on rate of
health impact per 100,000
UV Exposure Weighted
by Action Spectrum
(TU] ' Radiation Module)
Biological Amplification Factor
(Statistical Regression Analysis Dose
Response Curve)
Population data
J
Historical data on
rate of health
impact per 100,000
Population-Weighted % Change
in UV Exposure
(Exposure Module)
Determine the Absolute Number of
Additional Cases/Deaths
(Effects Module)
Amount of Population
Affected Given Baseline
Incidence
The AHEF's ability to accurately project changes in ozone layer depletion is critical to its purpose of
estimating the health benefits associated with various policy changes. This report summarizes
updates to the AHEF module known as the "Ozone Maker," which projects ozone depletion based on
global ODS emissions profiles (in the "Project Ozone Depletion" module, as shown in Figure 1], These
updates are two-fold: (1] updates to the input parameters and calculations in the Ozone Maker; and
(2] replacing the global ODS emissions profiles previously in use by AHEF with those developed for the
World Meteorological Organization's (WMO] Scientific Assessment of Ozone Depletion: 2010, which
1
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represented the most up-to-date understanding of ozone depletion at the time this report was being
finalized (WMO 2011], This report describes in detail each of these updates and provides an analysis
of how these changes affect the health benefits estimated by the AHEF. For a more comprehensive
description of the entire AHEF model, please see EPA (2006] and EPA (2010], as briefly described in
Box 1.
This report is organized as follows:
¦ Chapter 2 revises the approach in the development of global emissions profiles for use in AHEF
by incorporating the global ODS emissions profiles from WMO's 2010 assessment
¦ Chapter 3 presents updates to the ozone projections module, including updates to the input
parameters and calculations of equivalent effective stratospheric chlorine (EESC] and total
column ozone.
¦ Chapter 4 evaluates the overall changes in EESC, total column ozone, and estimated health
benefits associated with the updates to the AHEF as described in Chapters 2 and 3.
¦ Chapter 5 provides a description of potential future work including the proposed methodology
for developing future global ODS emissions profiles to reflect new policy scenarios.
Box 1: Previous Updates and Peer Reviews of the AHEF
The AHEF was significantly updated in 2003 to incorporate new data and findings from various
research projects. These revisions included: (1] recalibrated and refined stratospheric ozone
concentration measurements; (2] improved forecasts of the impact of changing ozone concentrations
on ultraviolet (UV] radiation intensity at the Earth's surface; (3] updated information on the
biological effects of UV radiation of different wavelengths (action spectra], and how age and year of
birth affect the induction of skin cancers and other human health effects; (4] improved estimation of
projected skin cancer mortality rates, based on more recent and reliable epidemiological data; (5]
removal of the cataract module until an agreed upon dose-response relationship became available;
and (6] updated population data. These updates were tested and presented in the EPA 2006 Peer
Reviewed Report, "Human Health Benefits of Stratospheric Ozone Protection."
In a 2010 peer-reviewed report, Protecting the Ozone Layer Protects Eyesight: A Report on Cataract
Incidence in the United States Using the AHEF Model, EPA reintroduced the model's capability to
estimate changes in cataract incidence by sex and skin type. The updates that enabled AHEF to model
cataract incidence included updated information on the biological effects of UV radiation, including
dose-response data by skin type and sex; and more recent epidemiological data.
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Chapter 2: UPDATING OPS EMISSION PROFILES
The AHEF requires input of global ODS emissions into the ozone projections module to estimate
latitudinal ozone projections (U.S. EPA 2012], Figure 2 represents the historical relationship between
ODS emissions and stratospheric ozone projections within the AHEF. While this figure represents the
traditional approach for developing global emissions profiles and ozone changes in the AHEF, this
methodology has been adjusted to accommodate other datasets on a scenario-by-scenario basis,
dependent on analytical needs. For example, for an analysis of stratospheric ozone impacts by high-
speed civil transport, calculations of ozone changes were based on results from the Commonwealth
Scientific and Industrial Research Organization (CSIRO] model (NASA/EPA 2001],
Figure 2: Schematic Diagram of Historical Method for Relating Emissions
to Stratospheric Ozone Projections in the AHEF
Apply
Ratio
from U.S.
to Global
Global Emissions
Profile
Vintaging
Model
U.S. Emissions
Profile
Historically, U.S. ODS emissions as estimated by EPA's Vintaging Model (VM] (described in Box 2
below] have been multiplied by a U.S.-to-global emission factor to extrapolate global ODS emissions for
use by the AHEF. This emission factor has been periodically revisited. In its initial design, AHEF used a
ratio of 40% United States, 40% Europe, and 20% Rest of World (ROW], The emission factor currently
in use was estimated in the 1990s, when U.S. ODS emissions represented roughly one-third of global
emissions (i.e., 33% U.S., 33% Europe, and 33% ROW],
Since the emission factor was last updated, relative contributions among these three segments has
evolved. Both developed and developing countries have made significant progress towards the
phaseout of ODS, and the Montreal Protocol has also been amended to control new chemicals and
accelerate the phaseout of hydrochlorofluorocarbons (HCFCs].3 The result is that developing
countries now account for a growing proportion of ODS emissions, while developed countries,
including the United States, account for a smaller proportion.
Given these trends and the flux in these emission relationships, it was determined that the emission
factor approach should be replaced with a new global ODS emission profile that reflected the Montreal
Protocol as currently amended. Updating the AHEF with a new global emissions profile allows
circumvention of the first three steps in the historical schematic shown in Figure 2 above, effectively
eliminating the need for a U.S.-to-global emissions factor.
3
The Parties to the Montreal Protocol have adjusted the Montreal Protocol five times since its initial adoption to
accelerate the reductions required on chemicals already covered by the protocol, including most recently in 2007
when the Parties adopted the 2007 Montreal Adjustment that accelerated the phaseout of HCFCs. The Parties have
also amended the protocol four times to enable the control of new chemicals, among other actions.
3
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Selection of a New Global Emissions Profile
Over the past decade, a number of
international ODS datasets have become
available. Appendix A presents 16 potential
datasets that were considered for the AHEF
based on criteria of authority, independence,
timeliness (i.e., how recent is the inventory],
global scale, data output (e.g., emissions,
production, or consumption], projected
timeline, and granularity. Ultimately, the WMO
A1 Baseline emissions profile detailed in the
WMO 2010 assessment was selected (WMO
2011], The WMO (2011] A1 Baseline
emissions profile accounts for the 1987
Montreal Protocol and its associated
amendments and adjustments through 2007.
This dataset provides species-specific data at a
global scale, is informed by observational data,
provides ODS emissions estimates from 1950
to 2100, is compiled based on a number of
recently developed international ODS datasets
(as described below], and is globally-
recognized as representing the current state of
the science.
The WMO (2011] A1 Baseline includes ODS
emissions from 1950 to 2100 based on
historical and projected mixing ratios, as
shown in Appendix B. The historical mixing
ratios are from 1950 to 2009 and are derived
from observations from NOAA and Advanced Global Atmospheric Gases Experiment (AGAGE] global
sampling networks. For years before ongoing observations are available, the historical mixing ratio
trends are derived from (1] when available, measured mixing ratios in firn-air samples, and (2]
modeled mixing ratios from consideration of industrial production magnitudes (e.g., the Alternative
Fluorocarbons Environmental Acceptability Study [AFEAS]]. The projected mixing ratios are based on
production of ODS reported to the United Nations Environment Program (UNEP], estimates of the
bank sizes of ODS for 2008 from the Technology and Economic Assessment Panel (TEAP]; approved
essential use exemptions for CFCs, critical-use exemptions for methyl bromide, and production
estimates of methyl bromide for quarantine and pre-shipment use. When NOAA and AGAGE
observations are available (this varies by species], the mixing ratio is an average of the two network
observations.4
There is inherent uncertainty associated with data on ODS emissions, whether they are derived from
top-down models, bottom-up models, or extrapolated from atmospheric measurements, and the WMO
2010 assessment is no exception. All datasets are affected by uncertainty in emissions profiles and
ODS characteristics, such as species lifetimes, transport of ODS to the stratosphere, composition of the
future atmosphere, and other factors.
4 See Table 5A-2 in the WMO (2011) report for detailed discussion of how the mixing ratio for each species was
developed.
4
Box 2: EPA's Vintaging Model
EPA's Vintaging Model (VM] estimates the annual
chemical emissions in the United States from
industry sectors that have historically used ODS,
including air conditioning refrigeration, foams,
solvents, aerosols, and fire protection. Within
these industry sectors, there are over 60
independently modeled end uses. The model uses
information on the market size and growth for
each end use, as well as a history and projections
of the market transition from ODS to alternatives.
Prior to the updates described in this report, the
AHEF's emission profiles were developed based on
the 1999 version of the VM. The VM is updated on
a regular basis to reflect changes in the market and
new industry information. Since 1999, the VM has
been significantly enhanced to expand the 40 end
uses provided in the 1999 version to now include
60 end uses, with new end uses added primarily in
the industrial and commercial refrigeration and
air-conditioning sectors. The VM has also been
updated to better reflect the lifetime and emissions
profiles of existing end uses, extend emissions
projections out to 2050, and account for the
accelerated phaseout schedule of HCFC
consumption agreed to by the Montreal Protocol
Parties in 2007.
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For the observation data used in the WMO dataset, there is uncertainty due to instrument calibration
and modeling errors. That said, these independent sampling programs for determining ODSs' global
mixing ratios have improved substantially over time, with differences now typically on the order of a
few percent or less (e.g., see Table 1-1 of WMO [2011]]. In addition, there is uncertainty in the future
bank projections that arises from estimates of the amount of material in the ODS bank reservoir and
the rate at which the material leaks or is released from the bank.
Comparison of ODS Emissions Profiles
This section compares (a] the WMO (2011] A1 Baseline global emission profile with (b] the emission
profile previously used in the AHEF, which was based on EPA's Vintaging Model and the application of
a U.S.-to-global emissions factor. For the purposes of this comparison, the former is called the WMO
(2011] A1 Baseline and the latter is called VM1999.
Each emissions profile contains emissions by ODS species and year to be used as input to the Ozone
Maker module. Table 1 provides a summary of the species data available from each emission data set.
A comparison was conducted across each like ODS species over time to illustrate potential differences
that could affect the AHEF simulation results.
Table 1: Comparison of Selected Global ODS Emission Data Sources5
Dataset
Source
CFCs
HCFCs
Other ODS
Years
Historical
Projected/
Modeled
VM1999
U.S. EPA
(2006]
11,12,
113,114,
115
22,123,
124,141b,
142b
CC14,MCF, Halon 1211,
Halon 1301
1936-1998
1999-2050
WMO
(2011]
A1
Baseline
WMO
(2011]
11,12,
113,114,
115
22,141b,
142b
CC14,MCF, Halon 1211,
Halon 1301, CH3Br,
Halon 1202, Halon 2402
1950-2009
2009-2100
To understand the implications of updating the AHEF emissions profiles to those developed for the
WMO 2010 assessment, each ODS species' emissions were compared as modeled by the VM1999 and
WMO (2011] A1 Baseline. This section describes the differences of the changes between CFCs and
HCFCs (see Appendix C for detailed figures comparing all ODS species].
Global CFC and HCFC emissions from 1980 to 2050 were visually compared for the VM1999 and WMO
(2011] A1 Baseline (see Figure 3], As shown, there is broad consistency between the two datasets
regarding the historical and projected emissions profile of CFCs. This consistency comes in part from
the step down requirements for the CFC phaseout mandated by the Montreal Protocol. Quantitative
comparison of these emission estimates suggests a 25% difference from 1980 to 2050. Overall, the
CFC emission estimates are within the same order of magnitude between the two datasets.
In Figure 3, the HCFC comparison reveals more disparity in the historical and projected emissions
between the two datasets, as would be expected because the phaseout of HCFCs has been accelerated
and the transition from HCFCs to alternatives is still underway. These curves suggest an approximate
50% difference between the two datasets. In part, this difference is because the VM1999 is derived
from U.S. emissions and the HCFC phaseout is further along in the United States than in countries
operating under Article 5(1] of the Montreal Protocol (i.e., developing countries].
5The VM1999 assumes a background concentration for methyl bromide.
5
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Figure 3: CFC and HCFC Emission Estimates
Comparison of Global CFC Emission Estimates
Comparison of Global HCFC Emission Estimates
5
1990 2000 2010 2020 2030 2040 2050
VM1999 WMO A1 Baseline
£ 400
1990 2000 2010 2020 2030 2040 2050 2060
VM1999 WMO A1 Baseline
Note: The jump in VM1999 HCFC emissions in 2045 reflects the retirement of foam stock blown with HCFCs; these
emissions may be controlled by future policy regimes. The WMO_Al_Baseline scenario represents the WMO (2011) A1
Baseline scenario.
A further comparison by CFC and HCFC species was conducted for the year 2000 (see Appendix C for a
more detailed comparison of how CFC and HCFC species emissions vary over time between the two
datasets], This individual species level of comparison is important, as the AHEF module that estimates
ozone depletion takes into account the different atmospheric properties of each ODS (e.g., atmospheric
lifetime, stratospheric release factors, and the number of reactive chlorine and bromine atoms]. Figure
4 illustrates ODP-weighted emission contributions of CFCs by species included in each dataset for the
year 2000.6 CFC-12 represents the largest contributor to ODP-weighted CFC emissions for both
datasets, followed by CFC-11, while ODP-weighted emissions of CFC-114 and CFC-115 are minimal in
2000.
Figure 4: ODP-Weighted CFC Emission Contribution in 2000
350
5 250
CFC-115
CFC-114
CFC-113
CFC-12
CFC-11
NOAA
VM 1999
VM 2011
TEAP
6 CFCs and HCFCs contributing 0.5% or less to the total CFC or HCFC emissions, respectively, are not represented in
the figures. The ODPs used for CFC species are as follows: 1 for CFC-11; 0.82 for CFC-12; 0.85 for CFC-113; 0.58 for
CFC-114; 0.57 for CFC-115.
6
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Similarly, Figure 5 compares the relative ODP-weighted contribution of each HCFC species for the year
2000.7 The VM1999 dataset provides estimates for all HCFC species; the WMO (2011] A1 Baseline
dataset provides estimates of all species except HCFC-124 and HCFC-123. For both datasets, HCFC-22
is the greatest contributor to OPD-weighted HCFC emissions. HCFC-141b represents a fairly consistent
portion of the ODP-weighted HCFC emission total for each of the datasets. The contribution of the
remaining HCFCs to total ODP-weighted HCFC emissions varies with each dataset
Figure 5: ODP-Weighted HCFC Emission Contribution in 2000
HCFC-142b
I HCFC-141b
HCFC-124
I HCFC-123
I HCFC-22
NOAA
VM 1999
VM 2011
TEAP
As expected, this comparison demonstrated some changes due to the updated input parameters for
EESC and in emissions by species when using the WMO (2011] A1 Baseline Scenario. Moving forward,
the AHEF will rely on the state-of-the-science WMO (2011] A1 Baseline emissions profile to represent
the effects of the Montreal Protocol as ratified in 1987 and all of its amendments and adjustments
through 2007. In the future, AHEF may be updated to account for new global emissions profiles
released as part of forthcoming WMO Ozone Assessments.
The next chapter further explores the implications of using the WMO (2011] A1 Baseline emission
profile on AHEF estimates of EESC, column ozone, and human health effects.
7 The following ODP values were used for HCFC species: 0.04 for HCFC-22; 0.02 for HCFC-123; 0.022 for HCFC-124;
0.12 for HCFC-141b; 0.07 for HCFC-142b.
7
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Chapter 3: UPDATES TO AHEF OZONE CALCULATIONS
The AHEF's ozone module (known as Lhe "Ozone Maker"] esLimaLes EESC and LoLal column ozone for a
given ODS emissions profile. This chapLer presents a descripLion of Lhe meLhodology and updaLes in
esLimaLing Lhe EESC and LoLal column ozone esLimaLes Lo reflecL Lhe stale-of-Lhe-science, and ouLlines
Lhe imparts of Lhese changes.
The Ozone Maker calculaLes Lhe annual LoLal ozone column for a series of laLiLude bands for a given
ODS emissions profile, where each ODS emissions profile represenLs a specific ODS policy scenario.8
This is calculaLed by applying Lhe following sysLemaLic sLeps:
• SLep 1. "EmiL" Lhe ODS emissions inLo Lhe aLmosphere and add Lhese emissions Lo Lhe
sLraLospheric ODS concenLraLion, assuming a Lhree year lag for Lhe emissions Lo reach Lhe
sLraLosphere. These sLeps are repealed from 1950 Lo 2100.
• SLep 2. CalculaLe Lhe equivalenL effecLive sLraLospheric chlorine (EESC] based on Lhe
sLraLospheric ODS concenLraLions. These sLeps are repealed from 1950 Lo 2100.
• SLep 3. CalculaLe LoLal column ozone by lalilude band and year for years 1978 Lo 2100 based
on Lhe EESC using linear regression.
• SLep 4. Apply assumplions Lo LoLal column ozone column Lo ensure Lhe projeclions do noL
exceed 1979-1980 LoLal column ozone amounls (i.e., "superabundance" of ozone] nor are
below 100 Dobson unils (DU].9
These calculalions require quanlified informalion regarding specific characlerislics of each ODS (e.g.,
almospheric lifelime, almospheric concenLraLion, EESC], The WMO's Scientific Assessment of Ozone
Depletion: 2010—which represenled Lhe mosL up-lo-dale underslanding of ozone deplelion al Lhis
wriling—provides minor Lo significanl updaLes of Lhese characle rislics. This section describes the
incorporation of those updaLes inLo Lhe AHEF (WMO 2011], In addilion, parls of Lhe EESC and ozone
calculalions in the AHEF were also updaled, as described in further detail below.
Updates to EESC Inputs and Impacts on Model Estimation
The methodology developed in Lhe mid-1990s conlinues Lo be Lhe appropriale approach for calculaling
EESC in Lhe AHEF ozone module, albeil updaled Lo reflect current condilions. The eslimale of each
ODS species' concentralion (i.e., ODS_CON] for a given year is as follows:
ODS_CON(y] = exp (-1/Ti] * ODS_CON;,;-i + (l-exp(-l/ I,]] * Ti *ODS;,;* Fsurf
where:
i is Lhe ODS species
j is Lhe year
ODS_CONy-i is Lhe almospheric concenlration of Lhe ODS species i of Lhe previous year j-1
X, is the almospheric lifelime of species z10
exp (-1/Ti] is the proportion of Lhe species i remaining after 1 year
8 Because 90% of the total ozone column is in the stratosphere, most of the ozone changes are also located in the
stratosphere (EPA 2001).
9 The average of two years, 1979 and 1980, is used to account for the effects of the quasi-biennial oscillation (QBO).
10 The atmospheric lifetime of a species is the time required for its initial concentration to decay to 1/e of its initial
value.
8
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ODSy is the global emission estimate for ODS species i during year j
FSurf is a factor that represents a general decrease of ODS mixing ratios with altitude above the
tropopause
This equation sums the concentration of the ODS species remaining in the atmosphere from the
previous year and the concentration of the newly emitted ODS species. A three-year lag is assumed
from the time ODS species are emitted to the time they reach the stratosphere.
The annual EESC contribution of each ODS species is calculated by multiplying ODS_CON(zj] by a
stratospheric chlorine/bromine release factor and the number of reactive moieties associated with the
ODS species (based on the fractional release rates]. If the species is a brominated compound then the
product is multiplied by an additional factor (alpha] that represents the impact of bromine compared
with chlorine in destroying stratospheric ozone. All EESC contributions are then summed for a global,
annual EESC estimate.
As noted above, WMO (2011] provides updated values for some input parameters for EESC, including
atmospheric lifetimes, the stratospheric chlorine/bromine release factors, the conversion factor
(kt/ppt]11, FSurf factor, and the alpha factor. The AHEF was updated to incorporate each of these new
values, which are shown in Table D.l in Appendix D. In addition, the Ozone Maker module was
updated to include emissions of Halon 1202 and Halon 2402, two ODS that were previously excluded
from the model. The updates that affect the estimates of total EESC are as follows (using the WMO
(2011] A1 Baseline emission profile as presented in Chapter 2]:
• The updates to the conversion factor (kt/ppt] slightly decreased the EESC associated with CFC-
11, CFC-12, carbon tetrachloride (CCU], and methyl bromide (CI-hBr].12 The changes in the
alpha factor (from 55 to 60] slightly increased the bromine contribution to total EESC. The
introduction of the Fsurf factor increases the estimated total EESC from 1990 to 2100 by
approximately 9 percent. However, there are no noticeable differences when comparing the
estimates of total column ozone.
• The changes in the atmospheric lifetime reduced the contribution of the EESC associated with
CCI4, methyl chloride (CH3CI], and CI-hBr to total EESC and increased the contribution of the
EESC associated with CFCs and Halon 1202 and 1211 (see Figure 6], Overall, the change in
lifetime reduced the total EESC by approximately 2 3 percent, although this change will vary
based on the emissions policy scenario that is modeled; these results are based on a policy
scenario that includes all amendments and adjustments to the Montreal Protocol through the
2007 Montreal Adjustment (i.e., the WMO (2011] A1 Baseline scenario], as described further
in the next chapter.
11 The conversion factor was updated to reflect our current understanding of the mass of our atmosphere (i.e.,
5.148*1018 kg).
12
" The previous estimates were provided by the UNEP (1989) and have been updated in the interim.
9
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Figure 6: Contribution to total EESC by ODS species summed from 1950 to 2100 (left figure
illustrates percent contribution using previous lifetimes; right figure illustrates percent
contribution using revised lifetimes)13
The changes in the stratospheric release factors significantly reduced the estimated total EESC;
however, it was the differences in the slope of the estimated EESC from 1980 to 1990 (which is used to
scale the total column ozone] that had the greatest impact on the total column ozone estimates. These
factor updates reduced the total column ozone loss after 1995 and simulated an earlier return to 1980
baseline conditions (see Figure 7],
13
Halon 1202 and Halon 2402 are not included in this figure as the previous version of the OzoneMaker did not
include these species; thus, their associated stratospheric release factor was zero (i.e., the algorithms for Halon
1202 and Halon 2402 are not fully functional until the next step updating the stratospheric release factor). CFC-
115 contribution is not included as it is extremely small: 0.03% when using previous lifetimes and 0.1% when
using the updated lifetimes.
CH3Br
19.6%
CH3Br
22.6%
Halonl211
3.5%
CH3CI
25.1%
^K_CFC-113
Br 3.0%
Halonl211 0.7%
3.6%
Halonl301
3.0%
CH3CI
29.0%
Halonl301
3.9%
HCFC-142b
0.2%
HCFC-141B
0.7%
HCFC-22 _CH3CCI3
1.3% 2.4%
HCFC-142b
0.1%
HCFC-141b \_HCFC-22
0.6% 1.0%
10
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Figure 7: Comparison of total EESC and total column ozone using the previous and updated
stratospheric release factors (40°N-50° North)14
3500
2500
2000
U
(/> 1500
•WMO (2011) A1 Baseline with revised stratospheric release factors
WMO (2011) A1 Baseline with previous stratospheric release factors
355
330
325
o
oo
cn
o
cn
cn
o
o
o
r\i
O
r\i
O
r\i
O
r\i
O
m
O
r\i
O
O
rvi
O
LD
O
rvi
O
iX)
O
rvi
O
o
rvi
O
oo
O
rvi
O
CT)
O
rvi
O
O
WMO (2011) A1 Baseline with revised stratospheric release factors
— — WMO (2011) A1 Baseline with previous stratospheric release factors
Note: Circle markers indicate the maximum (EESC] and minimum (column ozone] values.
14 The total column ozone is estimated with the updates to the ozone calculations as discussed in Section 3.2.
11
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Updates to Ozone Calculations and Impacts on Model Estimation
Under the assumption that EESC concentrations will continue to drive the changes in stratospheric
ozone concentrations, the calculation of total column ozone as a function of EESC, latitude, and month
uses the following scaling equation which is identical to that used in the WMO 1998 report (WMO
1999]:
A(lat,mori)
O3(year,lat,mon) — 03(1980, lat,mori) = [EESC (year, lat,mon) — EESC(1980, lat,mon)]
B
where:
O3 is total column ozone (in Dobson units [DU]]
A is the ozone trend from 1980 to 1990 by latitude and month (e.g., DU per decade]
B is the global EESC trend during the same period (e.g., in ppb per decade]
The coefficient A was based on data from measurements obtained by the Total Ozone Mapping
Spectrometer (TOMS] version 7.15 The ozone concentrations in 1980 and the ozone trend from 1980
to 1990 used to derive the A coefficients are presented in Tables D.2 and D.3 in Appendix D (these
values have been updated to reflect the state-of-the-science]. The coefficient B was found to be 438
parts per trillion per volume (ppt] per decade using the methodology above to estimate EESC under
the WMO (2011] A1 Baseline scenario. Further, the B coefficient is now calculated for each AHEF
simulation based on the EESC estimated specifically from a given emissions profile. This linear
relationship described by the scaling equation above is considered to be reasonable for mid-latitudes
which experience relatively small ozone changes, unlike the Antarctic where an EESC threshold leads
to non-linear ozone responses (WMO 1999], For use in AHEF, total column ozone values are
restrained from dropping below 100 DU, given this is far outside the range of any expected future mid-
latitude values, or exceeding the 1979-1980 baseline values.
The WMO 1998 report was used for this update because it was the last of the WMO reports to provide
a simple approach in equating EESC to stratospheric ozone. The WMO 2002, 2006, and 2010 reports
use more complicated models to calculate ozone concentrations that introduce additional factors into
Box 3: Climate Change Impacts on Ozone
As discussed in the WMO 2010 report,
potential changes in climate may lead to
changes in atmospheric circulation and
chemistry that affect ozone recovery, e.g.:
¦ Cooling of the stratosphere may cause
ozone levels to increase in the middle to
upper stratosphere at low- and mid-
latitudes.
¦ Accelerating the Brewer-Dobson
circulation could lead to a decrease in
column ozone in the tropics and
increases elsewhere.
¦ Increasing the transport of ozone from
the stratosphere to the troposphere.
15 McPeters etal. (1996) provided the TOMS data. Dr. Sasha Madronich, a lead author of WMO 1998 report,
provided these data for use in the AHEF.
the calculation (e.g., interactions of tropospheric and
stratospheric chemistry with climate-driven changes
to temperatures and global circulation patterns,
please see Box 3],
A major advantage of using the simple linear model
described here for a policy model is that the effects of
different individual ODS species can be compared on
a common basis (the EESC] and summed to give the
total effect. This linear superposition allows
estimation of the fraction of the total O3 depletion
(and related health effects] that is directly
attributable to the emissions of any individual ODS
species. This allows for a systematic understanding
of the relationship between reducing an ODS species
as dictated by a potential policy scenario and the
12
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impact on total column ozone, and this type of first-order understanding helps inform policymakers.
By contrast, in a fully coupled chemistry-climate model (e.g. WMO 2002, 2006, 2010] each ODS
emission profile would have to be considered in the context of all of the other ODS emission profiles,
and the individual species effect would be much more difficult to isolate.16 In addition and as
importantly, each fully coupled chemistry-climate model generally requires significant time and
resources to run a simulation for each ODS emissions profile. Conversely, the linear model described
here provides a means for efficiently comparing relative health effects across ODS emissions profiles
(policy scenarios].
The updates to estimating the total column ozone, including updating the emission profile from
VM1999 to WMO (2011] A1 Baseline, affect the predictions by (see Figure 8 below]:
• Estimating a slightly closer alignment of the 1980 total column ozone amounts with satellite
observations (e.g., total column ozone is estimated to be about 350 DU for the 40°N-50°N
latitude band]; and
• Reducing total column ozone loss in the 1990s by approximately 3 percent (e.g., loss is
reduced by about 10 DU for the 40°N-50°N latitude band].
The ozone updates did not significantly affect the anticipated recovery of ozone to 1979-1980 levels
by 2040.
Figure 8: Comparison of total column ozone estimates using previous and updated ozone
calculations (40-50° N)
355
Previous ozone calculation (VM1999)
Updated ozone calculation (VM1999)
Updated ozone calculation (WMO (2011) A1 Baseline)
Note: Circle markers indicate the minimum column ozone values.
16 This methodology incorporates some simplifications. For example, it does not consider how climatic changes in
the atmosphere may affect the relationship between EESC and ozone (WMO 1999). Though a more complicated
chemistry-climate model might capture some of these changes, the methodology described here is transparent, is
calibrated with historically observed ozone and EESC changes, and (importantly in the context of the AHEF) it
allows, via linear superposition, separation and evaluation of the impacts of each individual ODS compound.
13
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Chapter 4: RESULTS OF UPDATES
This chapter investigates the net result of the updates to EESC and ozone calculations, as presented in
Chapter 2, as well as the result of switching to the new WMO (2011] A1 Baseline emission profile as
described in Chapter 3. The following AHEF outputs are systematically compared using VM-based
simulations and the new WMO-based simulations:
• Estimated EESC: The Ozone Maker module estimates the total EESC by year for each ODS
emissions profile representing a given ODS policy scenario (see section entitled "Comparison
of EESC" for a description of these calculations], A comparison was conducted for two
purposes: (1] to consider how the AHEF calculations of EESC compared with that estimated
across WMO reports; and (2] to consider how the EESC estimates differ between those derived
with the AHEF and those provided in the WMO 2010 assessment.
• Estimated total column ozone: After calculating EESC, the Ozone Maker module estimates
the total column ozone as a function of year and latitude-band (see section entitled
"Comparison of Ozone" for a description of these calculations]. Predictions of total column
ozone for 1980 through 2100 were compared for the VM1999 and WMO (2011] A1 Baseline
simulations.
• Estimated health benefits: As a last step in the analysis, human health benefits were
estimated for two purposes: first, to understand the implications for the level of health
benefits estimated using the WMO (2011] A1 Baseline simulation compared with the VM1999
simulation; and second, to understand the human health benefits associated with various
policy scenarios based on WMO emissions profiles. Box 4 below briefly describes the process
for estimating human health effects in the AHEF and each of the health effects estimated:
cutaneous malignant melanoma, non-melanoma skin cancer, and cataract.
The 2006 EPA peer-reviewed report, Human Health Benefits of Stratospheric Ozone Protection,
compared the historical and projected levels of EESC—a measure of chlorine loading in the
stratosphere—and ozone in the stratosphere under the AHEF and the World Meteorological
Organization's (WMO] Scientific Assessment of Ozone Depletion, 1998 (WMO 1999], The 2006 EPA
report used an emissions profile representing the changes in ODS emissions through the Montreal
Amendments of 1997.
This effort builds on the 2006 report by also comparing VM-derived stratospheric ozone
concentrations under an emissions profile representing the 1987 Montreal Protocol and all
adjustments through 2007, and the concentrations produced using the emissions profile outlined in
the WMO Scientific Assessment of Ozone Depletion, 2010 (WMO 2011],
Specifically, the emissions simulated for each species, the trends in stratospheric ozone levels for the
northern mid-latitudes (40°N-50°N] as well as associated EESC values were examined from baseline
ozone conditions through recovery as projected by the VM1999 and the WMO (2011] A1 Baseline
scenarios. In addition, updated health benefits associated with WMO policy scenarios were
determined. Results are presented below.
14
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Box 4: Estimating Human Health Effects in the AHEF
Each health effects module in the AHEF determines the change in incidence that will occur based on a
relative change in UV dosage (i.e., the number of health effect cases that occur comparing a scenario
case to the 1979-1980 baseline conditions]. The AHEF assumes that sun exposure behavior remains
the same in the scenario and baseline, unless otherwise modeled. While the health effects module
calculates baseline incidence uniformly across population groups, it uses updated biological
amplification factors (BAFs) to investigate the health effect risk by skin type and sex. The health effects
module uses the following equation to estimate the change in the incidence for a health effect for each
U.S. County:
Health Effect Incidence=[UVexp] (BAFByPopGroup) (BaselineIncidenceByPoPGrouP,Year) (P o p u 1 a ti o n i ly i>„ P(I|0 u p, Yca,}
where: Health Effect Incidence is the increase in incidence from scenario to baseline, UVexpis the
cumulative percentage increase in UV exposure, BAFByPopGroup is the biological amplification factor for
the health effect as a function of population group (skin type and sex], BaselineIncidenceByPoPGrouP,Yearis
the baseline incidence estimates of the health effect for each population and cohort group, and
PopulationByPopGroup.Yearis the population for each population group by year and age. Additional detail is
available in the U.S. EPA (2006] and U.S. EPA (2010] reports, including discussions of uncertainty.
Each of the human health effects estimated by the AHEF is briefly described below.
Cutaneous Malignant Melanoma (CMM) Incidence Rates. CMM is a potentially life-threatening
disease in which malignant (cancer] cells form in the skin cells called melanocytes, found in the lower
part of the epidermis. A limited set of data on CMM incidence was extracted from the Surveillance,
Epidemiology, and End Results (SEER] Program, based within the Cancer Control Research Program at
the National Cancer Institute (NCI], This data set was aggregated into 18 age groups by sex, race (all
races, light-skinned, and darker-skinned], and the three latitudinal U.S. regions.
Cutaneous Malignant Melanoma (CMM) Mortality Rates. Baseline CMM mortality data for the years
1950 through 1984 were obtained from a EPA/NCI data set, which reports deaths from CMM in
individuals for 18 age groups, by sex and race, covering every county in the United States.
Non-Melanoma Skin Cancer (NMSC) Incidence Rates. Basal cell carcinoma (BCC] and squamous
cell carcinoma (SCC] are both forms of NMSC. BCC and SCC cancers originate from cells of the outer
layer of the skin (called the epidermis] and rarely spread to other parts of the body. The incidence
rates by age, region, and sex were developed by U.S. EPA (1987] and Fears and Scotto (1983], based
on a nationwide survey in eight cities across the United States from 1977 to 1978.
Non-Melanoma Skin Cancer (NMSC) Mortality Rates. The baseline mortality data by county for BCC
and SCC were obtained from the EPA/NCI data set. The number of deaths included in this data set is
somewhat uncertain, due to ambiguities in the reporting and recording of information on death
certificates.
Cataract Incidence Rates. Cataract is a clouding of the eye's naturally clear lens, which can cause
vision impairment and blindness. Age-related cataract has a number of potential causes, but lifelong
exposure to ultraviolet radiation from the sun plays a significant role. The cataract baseline incidence
estimates are derived from National Health and Nutrition Examination Study (NHANES) data. The
study consists of 2,225 subjects between the ages of 45 and 74 at 35 different locations across the
United States Incidence estimates are stratified by location, based on the three latitudinal bands (20-
30°N, 30-40°N, and 40-50°N). Factors included skin type, sex, and population data (U.S. EPA 2010).
For additional methodological detail, please see prior AHEF peer-reviewed reports EPA (2010) and EPA
(2006).
15
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Comparison of EESC
EESC estimates were compared using the AHEF-
derived emissions profile and the WMO reports (see
Figure 9], The EESC trend lines are relatively
similar for the VM-derived EESC and WMO 1998,
2002, and 2006. Likewise, the EESC predicted by
the AHEF and WMO 2010 assessment for the WMO
(2011] A1 Baseline scenario are similar and
dramatically lower than all of the previous WMO
assessments. This is attributable to the fact that the
WMO 2010 assessment implemented a number of
changes to the modeling of the fundamental
properties of ODS.
The WMO 2010 assessment substantially revised
the halogen fractional release values based on new
research presented by Newman et al. (2007], That
study used the National Aeronautics and Space
Administration (NASA] ER-2 field campaign
observations to estimate fractional release values
using a method that accounts for the age-of-air.17
This new methodology has a significant impact on
the fractional release values of CFC-12, HCFC-22,
CCU and Halon-1211. This revised methodology has
been incorporated into the AHEF, and estimates of
EESC compare well with those from the WMO 2010
assessment (see Chapter 2 for more discussion].
Figure 9 demonstrates that the algorithm now used 1
the WMO 2010 assessment values that utilize observ
Box 5: EESC Estimates
Factors that influence EESC estimates
include the estimated ODS emissions, the
degree of dissociation of each ODS species,
and the rate of transport to the stratosphere.
In the estimation of ODS emissions alone,
significant opportunity for variation exists.
For example, the VM-based emissions profile
estimates annual ODS emissions by
generating an annual emissions profile for
each ODS end use, by chemical, for all ODS-
consuming countries. Conversely, WMO
1998 (and WMO 2010] estimates of
emissions are derived from atmospheric
mixing ratio observations and an
understanding of chemical lifetimes. WMO
1998 future projections are based on
emission functions acting on the banks of
material yet-to-be emitted from end-use
categories with similar emissions patterns.
The WMO 1998 analysis assumes that the
banks by end-use categories are replenished
by sales, where sales are based on future
production and consumption estimates.
calculate EESC in the AHEF is consistent with
i values from 1980-1990.
17 This methodology is applied to all ODS except HCFC-141b and HCFC-142b, which are estimated using the
methodology outlined in WMO (2007).
16
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Figure 9: Comparison of VM-based and WMO EESC Estimates
4000
• -VM1999
WMO (2011)
3500
WMO (2011) A1 Baseline (AHEF)
WMO (1999)
3000
WMO (2003)
2500
WMO (2007)
>
+-»
Q.
Q.
2000
u
00
LU
LU
1500
1000
500
o
o
o
O
O
O
O
O
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00
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00
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CD
CD
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1
r\j
r\j
r\j
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r\j
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(N
(N
(N
r\j
Note: Circle markers identify peak EESC.
Sources: WMO 1999; WMO 2003; WMO 2007; WMO 2011. All EESC estimates are based on the baseline scenario. The VM1999 simulation is based on the Montreal Protocol and all
adjustments through 2007.
17
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Comparison of Ozone
The AHEF-derived total column ozone (VM1999] was compared with the modeling reported in Figure
3-6 of the WMO 2010 assessment report and Figure 11-14 of the WMO 1998 assessment report as
illustrated in Figure 10 below.1819 20 In addition, the WMO (2011] A1 Baseline AHEF-derived
estimates of total column ozone are provided. The ozone assessments conducted by the WMO in 2002
and 2006 do not provide total column ozone associated with their EESC projections; therefore, direct
comparison was not possible.21 The WMO 1998 values are provided as a record of WMO estimates
made during a similar time period of the VM-derived total column ozone and hence rely on similar
scientific understanding as utilized in the previous AHEF calculations. However, the WMO 1998 values
do not account for additional ODS control measures implemented after 1997.
The WMO 1998 projections are based on annually- and monthly-averaged stratospheric ozone
concentrations for different latitudes as measured by NASA's Total Ozone Mapping Spectrometer
(TOMS] on the Nimbus-7 satellite. The WMO (2011] projections presented here represent the mean
total column ozone predicted by 17 multi-model chemistry-climate models (CCM].22 Unlike the AHEF,
these CCMs account for the impact of climate change on stratospheric ozone concentrations. The WMO
2010 assessment provides a lower and higher limit of the 95 percent prediction interval around the
mean multi-model ensemble estimate to account for the spread among the 17 CCMs.
As illustrated in Figure 10, both the AHEF- and WMO-based estimates indicate that stratospheric
ozone concentrations reached minimum levels in the late 1990s. The U.S. Global Change Research
Program similarly projected that concentrations of ODS in the atmosphere would peak before the year
2000 (USGCRP 1998], Figure 10 also shows that the AHEF-based estimates and those from the WMO
1998 Assessment are in agreement regarding the speed of ozone recovery, both projecting full
recovery to 1980 levels around 2045 for the northern mid-latitudes.23 The WMO 2010 assessment
ensemble model average predicts recovery to 1980 levels much sooner, in approximately 2020, while
the lower bound of the 95 percent prediction interval about the mean multi-model ensemble estimates
recovery at about 2030 (represented by the lower bound of the model ensemble average on Figure
10]. The upper bound of the model ensemble average in Figure 10 is not readily comparable to VM-
based estimates or to observed column ozone values.
18 This comparison provides the total column ozone levels only for the Montreal Adjustment policy scenarios that
included predictions of chlorine and bromine levels in the atmosphere.
19 Trend lines provided in Figure 9 and Figure 10 were extrapolated from a hard-copy analysis of available figures.
20 Differences in the specification of northern mid-latitude bands may affect this comparison. AHEF values
represent total column ozone across the 40°N to 50°N latitude band, WMO 1998 values are provided at 45°N
latitude, and WMO 2010 values are provided for the 35°N to 60°N latitude band.
21 Further, the WMO 2002 and 2006 assessments incorporate revised assumptions regarding HCFC production
levels. Thus, the WMO 2002 and 2006 EESC projections are lower than the WMO 1998 projections. Without the
revised ozone concentration projections associated with this lower EESC scenario, it is unclear how the WMO 2002
and 2006 ozone concentration projections compare with AHEF in terms of ozone concentration predictions and
how these changes in ozone concentrations would affect incremental health effects.
22 The WMO 2010 assessment provides 1980 baseline-adjusted multi-model trend estimates of annually averaged
total column ozone for mid-latitudes. In Figure 12, for purposes of comparison, these estimates have been adjusted
using the data presented in Table 3-3 of the WMO 2010 report, where the baseline of annually averaged total
column ozone in 1980 is 353 Dobson units for the northern mid-latitudes. In the WMO 2010 report, the
Intergovernmental Panel on Climate Change (IPCC) Special Report Emission Scenarios (SRES) A1B (a moderate
scenario) was used to project greenhouse gas emissions. The ODS concentrations were based on observations from
a number of sources, plus the adjusted A1 scenario (termed "baseline") as detailed in WMO (2007) Table 8-5.
23 As the purpose of the AHEF is to calculate benefits associated with reaching ozone layer recovery through ODS
controls, the model does not allow stratospheric column ozone levels to exceed baseline conditions. In contrast, the
WMO 2010 assessment does not cap ozone recovery atbaseline levels.
18
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It is important to note that the modeling simulated in the WMO 2010 assessment considers factors that
were not available in previous modeling efforts, including changes in meteorology and chemistry
brought about by projected increases in the concentrations of the greenhouse gases carbon dioxide,
methane, and nitrous oxide, as described earlier in this report in Box 3. In addition, the WMO 2010
assessment notes that natural variability, including, for example, influences of volcanic eruption and
solar cycle variations, will likely complicate prediction of when actual recovery occurs. Regardless of
natural variability and changing atmospheric parameters, the WMO 2010 assessment projects changes
in the atmosphere as a result of emissions of the major greenhouse gases will hasten ozone recovery
before the middle of the 21st century and its superrecovery thereafter.
Figure 10: Northern Mid-Latitude Total Column Ozone Comparison (40°N-50°N)
400
390
380
370
8. 360
350
^ Model Ensemble Average: Baseline (WMO 2011)
(shading indicates spread across models)
— • -Al: Baseline (WMO 2011 using AHEF)
340
330
— — VM1999
320
Al: Baseline (WMO 1999)
310
A3: Maximum Production (WMO 1999)
300
o
oo
CI
0
cn
01
o
o
o
o
o
o
Lfl
o
o
LO
o
o
O0
o
o
cn
o
o
o
m
o
o
Sources: WMO 1999; WMO 2011.
Finally, the AHEF-derived total column ozone based on the WMO (2011] Al Baseline emissions profile
demonstrates less reduction in ozone concentration compared with the previous estimate used by the
AHEF (VM1999], In addition, the AHEF-based estimates predict a minimum ozone concentration of
approximately 320 and 335 Dobson units (DU] for the northern mid-latitudes, while the WMO 1998
estimates indicate a minimum of approximately 335 DU and the WMO 2010 ensemble model average
estimates suggest an even higher minimum of approximately 345 DU. The primary reasons for the
difference between the minima predicted by the AHEF-based estimates are the revised global emission
factors, and the updated input parameters and methodology used to estimate EESC and ozone
concentrations.
Comparison of Health Benefits
In order to understand the implications for human health effects associated with the model updates
described in Chapters 2 and 3, this analysis used the AHEF to simulate health benefits using the
previous version of the AHEF (including the VM-based emission profile referred to as VM1999] and
the version of the AHEF updated as described in this report (including the new WMO (2011] Al
Baseline emission profile]. The health benefits modeled are those associated with the Montreal
Protocol as adjusted and amended through the 2007 Montreal Adjustment ("2007 Montreal
Adjustment"], as compared to a no policy controls scenario and as compared to the 1987 Montreal
19
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Protocol. Three categories of human health effects were compared: cataract incidence,
cutaneous malignant melanoma (CMM] incidence and mortality, and non-melanoma skin cancer
(NMSC] incidence and mortality, as presented in Table 2.
The updated WMO-based results show slightly fewer skin cancer mortalities and incidence avoided
than the previous VM-based results, when comparing the "2007 Montreal Adjustment" to "No Policy
Controls." These results reflect both the smaller reduction in total column ozone associated with the
updates to the AHEF as described in this report, as well as differences in the modeling of the "No
Controls" scenario between the previous VM-based AHEF and the updated WMO-based AHEF. When
comparing the "2007 Montreal Adjustment" to the "1987 Montreal Protocol," the updated WMO-based
results are similar to the previous VM-based results in terms of skin cancer mortalities and incidence
avoided. Appendix E presents the total column ozone modeled for each of these scenarios.
As shown, using the updated AHEF, when compared with a situation of no policy controls, full
implementation of the Montreal Protocol, including its Amendments and Adjustments, is expected to
avoid more than 280 million cases of skin cancer, approximately 1.6 million skin cancer deaths, and
more than 45 million cases of cataract in the United States for cohort groups in birth years 1890-
2100.24
Table 2: U.S. Hea th Benefits of the Montreal Protocol for Cohorts in Birth Years 1890-2100
Scenarios
AHEF
Health Effect: Avoided Cases / Deaths
Version
Skin Cancer Mortality
Skin Cancer Incidence
Cataract
NMSC
CMM
Total
NMSC
CMM
Total
Incidence
2007
Montreal
VM1999
567,300
1,289,200
1,856,500
328,228,200
10,017,000
338,305,200
51,481,600
Adjustment
compared
with No
Policy
Controls
WMO
(2011)
A1
Baseline
477,700
1,075,000
1,552,700
274,750,200
8,313,800
283,063,900
45,553,000
2007
Montreal
Adjustment
VM1999
264,000
586,900
850,900
150,752,900
4,522,600
155,275,500
24,607,200
compared
with 1987
Montreal
WMO
(2011)
A1
Baseline
264,200
587,700
851,900
150,716,600
4,520,000
155,236,500
24,675,000
Protocol
Totals may not sum due to independent rounding.
VM1999 reflects the AHEF model used prior to the updates made as described in this report; WMO (2011JA1 Baseline
reflects the updates made to the AHEF as described in this report.
24
The AHEF generates results for five-year cohorts for birth years 1890 through 2100. For more detail, please see
U.S. EPA (2006).
20
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Chapter 5: FUTURE MODELING AND RESEARCH
This chapter describes both how the updated AHEF can be used for future analyses, as well as
opportunities for further research and updates to the AHEF model.
Emissions Profiles for Future ODS Control Policy Scenarios
The AHEF is used to model human health benefits associated with ODS control policy scenarios both in
the United States and the rest of the world. Changes in human health benefits are simulated by
comparing two global emissions profiles—one representing the baseline (typically emissions
associated with implementation of the Montreal Protocol and its amendments and adjustments
through the 2007 Montreal Adjustment, which is provided by the WMO (2011] A1 baseline in the
updated AHEF] and one representing the policy scenario. As such, the driver of the change in human
health benefits is the delta between the baseline and policy scenario emission profiles.
The following approaches will be used to develop emissions profiles associated with future ODS
control policy scenarios in the United States and the rest of the world.
• Future U.S. ODS Policy Scenarios—EPA's Vintaging Model will be used to estimate changes in
U.S. emissions associated with a given future policy scenario.25 26 The change in U.S. emissions
associated with the future policy scenario will be added to global baseline emissions to
generate the global emissions profile associated with the policy scenario, as illustrated in the
equation below:
Global ODS Emissions (WMO (2011] A1 Baseline] + Change in U.S. Emissions (Using VM] = Scenario
Global ODS Emissions (New U.S. Policy]
• Future Rest-of-World ODS Policy Scenarios—For future policy scenarios in the rest of the
world (i.e., non-U.S.], available data sources will be reviewed to determine the best available
data for estimating changes in non-U.S. emissions. These sources might include country- or
region-specific emissions reports or modeling, data reported as part of HCFC phaseout
management plans in developing countries, or consumption data reported under Article 7 of
the Montreal Protocol (scaled using consumption-to-emissions factors]. The change in rest-of-
world emissions associated with the future policy scenario will be added to global baseline
emissions to generate the global emissions profile associated with the policy scenario, as
illustrated in the equation below:
Global ODS Emissions (WMO (2011] A1 Baseline] + Change in Rest-of-World Emissions (Using
Available Data] = Scenario Global ODS Emissions (New Rest-of-World Policy]
In both cases, the AHEF will then be used to simulate the change in health effects associated with the
global scenario emissions as compared with the global baseline emissions.
25
Note that the WMO (2011) A1 baseline does not provide country-specific data that would enable modeling at the
country-level.
26 The Vintaging Model is regularly updated. Appendix F provides the changes that have occurred in the Vintaging
Model from the 1999 version through 2012.
21
-------
Future AHEF Updates
The AHEF is updated regularly to reflect new information and science. While this round of updates
incorporates new parameters for ODS characteristics and an updated global emissions profile, these
values are subject to future research and updates. If new parameters or new global emission datasets
become available in the future, these changes should be considered for the AHEF. In addition, future
updates should take into account the WMO Ozone Assessment schedule to align efforts with the state-
of-the-science.
22
-------
References
CCSP (2008], Trends in Emissions of Ozone-Depleting Substances, Ozone Layer Recovery, and
Implications for Ultraviolet Radiation Exposure. A Report by the U.S. Climate Change Science Program
and the Subcommittee on Global Change Research. [Ravishankara, A.R., M.J. Kurylo, and C.A. Ennis
(eds.]]. Department of Commerce, NOAA's National Climatic Data Center, Asheville, NC, 240 pp.
Hiller, R., R. Sperduto, and F. Ederer (1983], "Epidemologic associations with cataracts in the 1971-
1972 National Health and Nutrition Examination Survey," American Journal of Epidemiology, 118, 239-
249.
ICF (2011] AHEF Global ODS Emission Estimates Memorandum. Deliverable under EPA Contract# EP-
W-10-031, Task Order 3, Task 2.
IPCC/TEAP (2005] Special Report on Safeguarding the Ozone and the Global Climate System: Issues
Related to Hydrofluorocarbons and Perfluorocarbons. Available online at
.
IPCC (Intergovernmental Panel on Climate Change] (2001], Climate Change 2001: The Scientific Basis.
Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on
Climate Change. Edited by J.T. Houghton, Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. Dai, K.
Maskell, and C.A. Johnson. Cambridge, UK.
McPeters, R.D., S.M. Hollandsworth, L.E. Flynn, J.R. Herman, and C.J. Seftor (1996], Long-term ozone
trends derived from the 16-year combined Nimbus 7/Meteor 3 TOMS version 7 record, Geo Phys. Res.
Lett., 23, 3699-3702.
NASA (National Aeronautics and Space Administration] /EPA (Environmental Protection Agency]
(2001], Human Health Effects of Ozone Depletion From Stratospheric Aircraft. NASA/CR-2001-211160,
September 2001.
Newman, P.A., J.S. Daniel, D.W. Waugh, and E.R. Nash, (2007], A new formulation of equivalent effective
stratospheric chlorine (EESC], Atmos. Chem. Phys., 7 (17], 4537-4552, doi: 10.5194/acp-7-4537-2007.
Pitcher, H.M., and J.D. Longstreth (1991], "Melanoma mortality and exposure to ultraviolet radiation:
An empirical relationship," Environment International 17:7-21.
Ries, L.A.G., C.L. Kosary, B.F. Hankey, B.A. Miller, and B.K. Edwards (Eds.] (1999], SEER Cancer Statistics
Review, 1973-1996, National Cancer Institute, Bethesda, MD.
Sasaki H, Sakamoto Y, Schnider C et al. (2 009],"Exposure to the Eye as a Function of Solar Altitude,"
Optom VisSci. 86:e-abstract 95883.
Scotto, J., H. Pitcher, and J.A.H. Lee (1991], "Indications of future decreasing trends in skin-melanoma
mortality among whites in the United States," Int. J. Cancer 49:490-497.
UNEP (1989], Open-ended working group of the parties to the Montreal Protocol. First session of the
second meeting. Geneva, 13-17 November 1989.
http://ozone.unep.Org/Meeting_Documents/oewg/2oewg/2oewgl-4.e.doc
U.S. EPA (2001], Human Health Effects of Ozone Depletion from Stratospheric Aircraft, United States
Environmental Protection Agency, Washington, D.C.
23
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U.S. EPA (2006], Human Health Benefits of Stratospheric Ozone Protection, United States Environmental
Protection Agency, Washington, D.C. Available online at:
http://www.epa.gov/ozone/science/effects/AHEFApr20Q6.pdf
U.S. EPA (2010], Protecting the Ozone Layer Protects Eyesight: A Report on the Cataract Incidence in the
United States using the Atmospheric and Health Effects Framework, United States Environmental
Protection Agency, Washington, D.C. Available online at:
http://www.epa.gov/ozone/science/effects/AHEFCataractReport.pdf
U.S. EPA (2012], U.S. Vintaging Model (VM 10 file_v4.4_03.23.12], March 23, 2012.
U.S. EPA (2011], Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990 - 2009; Annex 3.
Available online at .
USGCRP (US Global Research Program] (1998], Depletion and Recovery of the Ozone Layer: An Update
on Scientific Understanding. USGCRP Seminar, 23 September 1998.
Velders et al. (2009], The large contribution of projected HFC emissions to future climate forcing.
Available online at < http: //www.pnas.Org/content/early/2009/06/19/0902817106.full.pdf+html>.
Velders et al. (2014], Uncertainty analysis of projections of ozone-depleting substances. Atmos. Chem.
Phys., 14,2757-2776.
WMO (World Meteorological Organization] (1999], Scientific Assessment of Ozone Depletion: 1998.
World Meteorological Organization Global Ozone Research and Monitoring Project - Report No. 44,
732 pp., Geneva, Switzerland.
WMO (2003], Scientific Assessment of Ozone Depletion: 2002. WMO Global Ozone Research and
Monitoring Project - Report No. 47, 498 pp., Geneva, Switzerland.
WMO (2007], Scientific Assessment of Ozone Depletion: 2006. World Meteorological Organization Global
Ozone Research and Monitoring Project - Report No. 50, 572 pp., Geneva, Switzerland.
WMO (2011], Scientific Assessment of Ozone Depletion: 2010. Global Ozone Research and Monitoring
Project - Report No. 52, 516pp., Geneva, Switzerland.
WMO (2014], Assessment for Decision-Makers: Scientific Assessment of Ozone Depletion: 2014. Global
Ozone Research and Monitoring Project—Report No. 56, 88 pp., Geneva, Switzerland, 2014
24
-------
Appendix A: Potential Global ODS and ODS
Substitute Data Sources
ICF reviewed potential data sets of global ODS or ODS substitute emissions or consumption estimates.
The table below summarizes this research.
Table A.1: Potential Data Sources
Source
Data Description
IPCC/TEAP Special Report
ODS emissions
Velders et al.
ODS emissions
UNEPTOC Reports
ODS emissions
WMO 2010 Scientific Assessment
ODS emissions
IPCCSRES
ODS emissions
SAP 2.4
ODS emissions
U.S. Proposed MP Adjustment
Analysis
HCFC emissions
UN Global Emissions Inventory
CFC-11, CFC-12, HCFC-22, & MCF
Activity vl
emissions up to 2000
UNEP Article 7 Data
ODS consumption
SRI Chemical Economics Handbook
ODS production and consumption
AFEAS
ODS production and sales
ICIS Fluorocarbon Profile
Fluorocarbon production capacity
EDGAR
ODS sub and HCFC-141 emissions
EPAGHG Reporting Program
ODS sub production
EPA Global Emissions Report
ODS sub emissions
UNFCCC
ODS sub emissions
25
-------
Appendix B: Emission Profile Estimates from 1950 through 2100
The emissions profile estimates emissions under the agreement of the Montreal Protocol and the adjustments thereafter through 2007. The global
emissions for each species based on the WMO (2011] A1 Baseline scenario are provided in Table B.l in 5-year increments (this is a condensed version of the
annual global emissions that are used to drive AHEF],
Table B.l: Emissions Profile in 5-year increments (million kilograms/year)
CFC-11
CFC-12
CFC-113
CFC-114
CFC-115
Halon
1211
Halon
1301
Halon
2402
CCI4
CH3CCI3
HCFC-22
HCFC-123
HCFC-124
HCFC-141b
HCFC-142b
CH3CI
CH3Br
Halon
1202
1950
22.8574
139.9813
31.0164
45.4441
0.0000
0.0000
0.0000
0.0
953.7000
0.0000
14.1000
0.0000
0.0000
0.0000
0.0000
0.0000
158.8000
0.0
1955
24.6074
50.3490
3.2329
7.5371
0.0000
0.0000
0.0000
0.2
85.0000
3.5132
2.9843
0.0000
0.0000
0.0000
0.0000
4098.5213
121.2648
0.0
1960
43.3472
93.1007
6.3662
6.8138
0.0000
0.0000
0.0000
0.6
110.0000
18.3556
7.6810
0.0000
0.0000
0.0000
0.0000
4253.6327
125.8279
0.1
1965
115.7651
185.9544
12.4258
8.2557
0.4438
0.0314
0.0053
1.0
127.0000
48.1159
20.5680
0.0000
0.0000
0.0000
0.0000
4397.8144
130.9230
0.1
1970
221.1475
321.7800
24.4944
10.0466
1.5387
0.3231
0.0432
1.5
127.0000
141.3837
43.7821
0.0000
0.0000
0.0000
0.0000
4488.8532
136.6585
0.2
1975
335.7847
442 .8850
48 .5050
15.0250
3.3970
1.3409
0.5241
2.1
127.0000
309.1173
70.7375
0.0000
0.0000
0.0000
0.819
4533.2636
143.1641
0.3
1980
274.0146
390.4361
82.8830
14.0896
5.9783
3.3922
1.8048
1.7
128.6600
521.2403
111.7820
0.0000
0.0000
0.0000
1.9403
4552.2507
150.5889
0.5
1985
342.3122
438.0398
160.1091
16.2738
9.2577
6.9592
3.9975
1.04
126.3453
558.7162
137.2363
0.0000
0.0000
0.0000
1.2584
4559.9204
159.0940
0.60
1990
267.0432
365.7519
215.5177
9.8409
10.8942
11.4968
5.1195
0.84
97.5896
627.6498
186.2219
0.0000
0.0000
0.1167
10.2377
4562.9512
168.8310
0.16
1995
121.2463
206.3803
33.3735
4.6242
7.9869
10.1091
0.3941
0.87
83.4474
181.7037
221.3669
0.0000
0.0000
41.7831
23.4046
4046.4564
174.2125
0.02
2000
94.8671
143.5285
14.0971
3.2026
3.3543
9.1399
1.2637
0.58
73.5276
22.8112
243.9201
0.0000
0.0000
58.6655
27.4412
4564.3715
159.7707
0.00
2005
76.4778
90.1100
9.5249
1.5946
0.5381
7.3251
1.9588
0.38
64.9722
6.9742
296.9958
0.0000
0.0000
43.8576
26.7501
4564.3715
146.9916
0.00
2010
63.8254
43.3557
3.9089
1.1928
0.3067
4.7718
1.7348
0.25
45.7034
6.9039
423.2003
0.0000
0.0000
59.3971
39.8256
4564.3715
138.3578
0
2015
49.3868
19.2372
0.1222
0.7043
0.2772
3.2314
1.4145
0.17
33.5419
0.0000
460.5124
0.0000
0.0000
76.7610
43.5939
4564.3715
136.3216
0
2020
38.2146
8.5356
0.0038
0.4159
0.2506
2.1883
1.1534
0.11
24.6166
0.0000
397.0638
0.0000
0.0000
81.7833
38.8861
4564.3715
136.3216
0
2025
29.5697
3.7873
0.0001
0.2456
0.2265
1.4819
0.9404
0.07
18.0662
0.0000
289.4512
0.0000
0.0000
77.4661
30.5318
4564.3715
136.3216
0
2030
22.8805
1.6804
0.0000
0.1450
0.2048
1.0035
0.7668
0.05
13.2589
0.0000
168.7107
0.0000
0.0000
66.3265
20.9624
4564.3715
136.3216
0
2035
17.7045
0.7456
0.0000
0.0856
0.1851
0.6796
0.6252
0.03
9.7307
0.0000
68.8811
0.0000
0.0000
51.9305
12.0879
4564.3715
136.3216
0
2040
13.6994
0.3308
0.0000
0.0506
0.1673
0.4602
0.5098
0.02
7.1414
0.0000
30.0586
0.0000
0.0000
40.6567
7.0371
4564.3715
136.3216
0
2045
10.6003
0.1468
0.0000
0.0299
0.1512
0.3116
0.4157
0.01
5.2411
0.0000
11.1439
0.0000
0.0000
31.4594
3.9296
4564.3715
136.3216
0
2050
8.2023
0.0651
0.0000
0.0176
0.1367
0.2110
0.3389
0.01
3.8465
0.0000
4.1315
0.0000
0.0000
24.3427
2.1943
4564.3715
136.3216
0
2055
6.3468
0.0289
0.0000
0.0104
0.1236
0.1429
0.2764
0.01
0.0000
0.0000
1.5317
0.0000
0.0000
18.8359
1.2253
4564.3715
136.3216
0
2060
4.9110
0.0128
0.0000
0.0061
0.1117
0.0968
0.2253
0.00
0.0000
0.0000
0.5679
0.0000
0.0000
14.5748
0.6842
4564.3715
136.3216
0
2065
3.8001
0.0057
0.0000
0.0036
0.1010
0.0655
0.1837
0.00
0.0000
0.0000
0.2105
0.0000
0.0000
11.2777
0.3821
4564.3715
136.3216
0
2070
2 .9404
0.0025
0.0000
0.0021
0.0913
0.0444
0.1498
0.00
0.0000
0.0000
0.0781
0.0000
0.0000
8.7265
0.2134
4564.3715
136.3216
0
2075
2.2752
0.0011
0.0000
0.0013
0.0825
0.0301
0.1221
0.00
0.0000
0.0000
0.0289
0.0000
0.0000
6.7524
0.1191
4564.3715
136.3216
0
2080
1.7605
0.0005
0.0000
0.0007
0.0746
0.0204
0.0996
0.00
0.0000
0.0000
0.0107
0.0000
0.0000
5.2249
0.0665
4564.3715
136.3216
0
2085
1.3623
0.0002
0.0000
0.0004
0.0674
0.0138
0.0812
0.00
0.0000
0.0000
0.0040
0.0000
0.0000
4.0429
0.0371
4564.3715
136.3216
0
2090
1.0541
0.0001
0.0000
0.0003
0.0609
0.0093
0.0662
0.00
0.0000
0.0000
0.0015
0.0000
0.0000
3.1283
0.0207
4564.3715
136.3216
0
2095
0.8156
0.0000
0.0000
0.0002
0.0551
0.0063
0.0540
0.00
0.0000
0.0000
0.0005
0.0000
0.0000
2.4206
0.0116
4564.3715
136.3216
0
2100
0.6311
0.0000
0.0000
0.0001
0.0498
0.0043
0.0440
0.00
0.0000
0.0000
0.0002
0.0000
0.0000
1.8730
0.0065
4564.3715
136.3216
0
26
-------
Appendix C: Comparison of Emission Profiles by
Species
As discussed in Section 3.3, this appendix provides additional figures that were used to inform the
comparison of the global ODS emissions developed through the VM-derived emissions profile and the
WMO (2011] A1 Baseline emissions profile by ODS species.
Figure C.l. Comparison of VM-derived and WMO (2011) A1 Baseline emissions profiles by ODS
species
400
350
300
i-
>
—
/SO
V)
c
200
o
w
1S0
fc
100
50
0
1950
2000
2050
2100
CFC-11 VM 1999
¦CFC-11 WMO A1
600
500
400
c 300
o
M 200
100
0
1950 2000
— CFC-12 VM 1999
I I
2050 2100
¦CFC-12 WMO A1
250
~ 150
K 100
1950 2000
— CFC-113 VM 1999
2050 2100
• CFC-113 WMO A1
25
20
i5- 15
Vt
c
o
S 10
E
0
1950 2000
— CFC-114 VM 1999
2050 2100
¦ CFC-114 WMOA1
27
-------
Figure CI. Comparison of VM-derived and WMO (2011) A1 Baseline emissions profiles by ODS
species cont.
12
10
0
1950 2000
— CFC-115 VM 1999
2050 2100
-CFC-115 WMO A1
1950 2000
— CCI4 VM 1999
2050 2100
¦CCI4 WMO A1
1950 2000
— CH3CCI3 VM 1999
2050 2100
• CH3CCI3 WM0A1
K 200
1950 2000
— HCFC-22 VM 1999
2050 2100
• HCFC-22 WMO A1
_yv_
90
80
70
60
50
40
30
20
10
0
1950 2000
— HCFC-141b VM 1999
2050 2100
¦HCFC-141b WMO A1
K 20
1950 2000
HCFC-142b VM 1999
2050 2100
»HCFC-142b WMO A1
28
-------
Figure CI. Comparison of VM-derived and WMO (2011) A1 Baseline emissions profiles by ODS
species cont.
1950 2000
Halon 1211 VM 1999
2050 2100
• Halon 1211 WMO A1
1.0
0.9
0.8
-0.7
£ °-6
¥ 0.5
o
S 0.4
E
m 0.3
0.2
0.1
0.0
1950 2000
Halon 1202 VM 1999
2050 2100
¦ Halon 1202 WMO A1
_yv_
7
6
5
4
3
2
1
0
1950 2000
Halon 1301 VM 1999
2050 2100
• Halon 1301 WMO A1
2.5
2.0
$15
Vt
c
o
S 1.0
E
0.5
0.0
1950 2000
Halon 2402 VM 1999
2050 2100
• Halon 2402 WMO A1
_yv_
200
180
160
140
120
100
80
60
40
20
0
1950 2000
CH3BrVM 1999
2050 2100
• CH3Br WMO A1
7000
6000
_ 5000
i-
£ 4000
vt
c
§ 3000
m 2000
1000
0
1950 2000
— CH3CI VM 1999
2050 2100
¦CH3CI WMO A1
29
-------
Appendix D: Parameters and Coefficients Used to
Inform the EESC and Ozone Calculations
Table D.l deLails Lhe parameLers used in AHEF in esLimaLing EESC by ODS species. The lifeLime,
sLraLospheric chlorine facLor, and Lhe alpha facLor are updaLed using Lhe esLimaLes provided in Lhe WMO
2010 report In addiLion, Lwo ODS species, Halon 2402 and Halon 1202, have been added. Given Lhe
WMO (2011] A1 Baseline emissions profile does noL include HCFC-123 and HCFC-124, Lhe
corresponding sLraLospheric chlorine release facLors are noL provided in WMO (2011], This
"inacLivaLes" Lhese species' conLribuLions Lo LoLal EESC. Finally, Fsurf, a parameLer LhaL effecLively
accounLs for a general decrease of ODS mixing raLios wiLh alLiLude above Lhe Lropopause, was defined as
1.07 for all ODS species excepL CFhBr. The Fsurf of CFhBr was 1.16 (Velders, 2014],
Since Lhe developmenL of Lhis report, updaLed lifeLimes have become available Lhrough Lhe WMO 2014
report and are provided in Lhe Lable below for reference (see "2014 Ozone Assessment']. The WMO
2014 assessmenLuses Lhe same sLraLospheric chlorine release facLors as used here.
Table D.l. The parameters used for each ODS species for estimating EESC
ODS Species
Current
.ifetime (years)
Previous 2014 Ozone
Assessment
Stratospheric
Chlorine Release
Factor
Current Previous
Alpha
Current
Factor
Previous
Number
of
Chlorine
Atoms
Conversion
Factor
(kt/ppt)
CFC-11
45
50
52
0.47
0.9
0
0
3
24.5
CFC-12
100
102
102
0.23
0.45
0
0
2
23.1
CFC-113
85
85
93
0.29
0.5
0
0
3
33.3
CFC-114
190
300
189
0.12
0.58
0
0
2
30.4
CFC-115
1020
1700
540
0.04
0.12
0
0
1
27.5
HCFC-22
11.9
12.1
12
0.13
0.315
0
0
1
15.4
HCFC-123
1.3
1.4
-
NA
1
0
0
2
27.1
HCFC-124
5.9
6.1
-
NA
0.4707
0
0
1
24.2
HCFC-141b
9.2
9.4
9.4
0.34
0.65
0
0
2
20.6
HCFC-142b
17.2
18.4
18
0.17
0.324
0
0
1
17.8
Halon 1301
65
65
72
0.28
0.72
60
55
0
26.5
Halon 1211
16
20
16
0.62
0.99
60
55
1
29.4
Halon 2402
20
77
28
0.65
0
120
110
0
46.3
Halon 1202
2.9
2.9
2.5
0.62
0.62
120
110
0
37.3
CH3Br
0.8
0.8
0.8
0.6
0.97
60
55
0
16.9
CCI4
26
42
26
0.56
0.95
0
0
4
27.4
CH3CCI3
5
4.9
5
0.67
0.9
0
0
3
23.7
CH3CI
1
1.5
0.9
0.44
0.99
0
0
1
9
"Current" refers to this report with values provided by the WMO (2011) Assessment; "previous" refers to previous
values in the AHEF.
The A coefficienLs by laLiLude and monLh are calculaLed as Lhe producL of Tables D.2 and D.3. The daLa in
Lhese lables were based on daLa measuremenLs obLained by Lhe Total Ozone Mapping SpecLromeLer
(TOMS] version 7 (McPeLers eLal. 1996; WMO 1999], wiLh Lrends derived from November 1979 Lo June
1991 (jusL before Lhe ML. PinaLubo erupLion which caused addiLional ozone perLurbaLions],
30
-------
Table D.2. Ozone Vertical Column (Dobson units) for 1980 by latitude band and month
Latitude
Month
Band
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
(°N)
20 to 30
261
264
274
288
299
296
293
283
283
275
266
266
30 to 40
311
324
335
334
336
321
307
301
291
283
283
302
40 to 50
364
398
398
392
378
356
333
319
307
313
313
336
50 to 60
388
418
440
426
404
375
352
330
321
330
330
345
60 to 70
0
408
455
448
413
371
342
319
311
0
0
0
Table D.3. Ozone trend (% per decade) from 1980 to 1990 by latitude band and month
Latitude Month
Band Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
(°N)
20 to 30
-2.1
-1.8
-1.0
-0.5
-0.5
-1.0
-1.4
-1.3
-0.9
-0.7
-1.1
-1.7
30 to 40
-4.2
-5.1
-4.4
-2.8
-1.6
-1.5
-2.2
-2.4
-1.7
-0.6
-0.7
-2.3
40 to 50
-3.7
-5.4
-5.8
-4.7
-3.0
-2.0
-2.0
-2.5
-2.2
-1.1
-0.5
-1.5
50 to 60
-0.7
-2.6
-4.3
-4.8
-4.1
-2.9
-2.4
-2.9
-3.3
-2.5
-0.8
0.2
60 to 70
0.0
0.0
-3.2
-4.6
-4.5
-3.5
-2.7
-3.0
-3.6
-2.7
0.0
0.0
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Appendix E: Total Column Ozone for Modeled
Policy Scenarios
Figure E-l presents total column ozone associated with three policy scenarios: no policy controls; the
1987 Montreal Protocol; and the Montreal Protocol as amended and adjusted through the 2007
Montreal Adjustment. Total column ozone is shown for two versions of the AHEF—the previous VM-
based AHEF as used prior to the updates made through this report; and the updated WMO-based AHEF
that incorporates the modeling changes described in this report. As shown, the total column ozone
modeled for the 1987 Montreal Protocol and 2007 Montreal Adjustment are relatively similar between
the VM-based and WMO-based versions of the AHEF; however, the no controls scenario is significantly
different, which has implications for estimating human health benefits relative to no policy controls.
Figure E-l: Total Column Ozone Associated with No Controls, 1987 Montreal Protocol, and 2007
Montreal Adjustment Policy Scenarios
3SO r
N o Controls
MP19S7
MA200?
wiuo-tuted
• N a Control!
MP1987
— — MA 2007
D
O
v
c
o
250
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Appendix F: Explanation of Differences between
VM1999 and VM2012
This table provides a description of the major VM updates that affect the emission estimates of each
species between VM1999 and VM2012. Future U.S. based policy scenarios would be developed using
the latest VM.
Table F.l: Explanation of Differences between VM1999 and VM2012
Species Differences Explanation for Differences
CFC-11
Emissions continue through 2050 in
VM4.4 (emissions end in 2039 in VM
1999), and are lower in VM4,4
Many Ref transitions away from CFC-11 began earlier
than 1996
CFC-12
Overall, lower emissions in VM4.4
Many Ref transitions away from CFC-12 began earlier
than 1996
HCFC-22
Higher emissions in VM4.4
Reflection of major uses of HCFC-22 as a CFC alternative
(most commonly used HCFC; used in Ref, AC, and foam
applications)
CFC-113
Latest VM phases out CFC-113 by
1996, otherwise, relatively similar
Emissions consistent with Montreal Protocol phaseout
schedule
CT (CCI4)
VM4.4 has much lower emissions,
which end in 1996
Emissions consistent with Montreal Protocol phaseout
schedule and niche solvent applications of CT
MCF
Similar emissions until 1996, VM4.4
emissions end
Emissions consistent with Montreal Protocol phaseout
schedule and niche solvent applications of MCF
CH3CI
None
NA
Halon 1301
Lower emissions in VM4.4 through
2032, Higher emissions in VM4.4
through 2050
Critical uses of Halon 1301 for fire suppression
Halon 1211
Lower emissions in VM4.4 through
2029, Higher emissions in VM4.4
through 2050
Critical uses of Halon 1211 for fire suppression
CH3Br
Not included in either version of VM
NA
HCFC-123
Lower emissions in VM4.4 through
2020, then higher emissions through
2050
Used as a flooding agent (through 2014) and chillers (no
phaseout)
HCFC-124
Lower emissions in VM4.4
Relatively small uses in Ref, sterilization, and FireExt
HFC-125
Introduced sooner in VM4.4; similar
emissions through 2030 then fewer
emissions than VM 1999 through 2050
Used as an alternative in flooding agents, chillers, IPR,
and other refrigeration equipment, but not the most
common ODS replacement for those end uses
HFC-134a
Higher emissions in VM4.4, not phased
out in latest VM
Reflection of the high uses of HFC-134a (most
commonly used HFC; used in Ref, AC, aerosols, and
foam applications)
HCFC-141b
Historically similar emissions; VM4.4
emissions higher between 2010 and
2040, then lower than VM 1999 from
2041-2050
HCFC-141b used in foams with long lifetimes (between
14 and 56 years)
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Table F.l: Explanation of Differences between VM1999 and VM2012 cont.
Species
Differences
Explanation for Differences
HCFC-142b
Introduced sooner in VM4.4 and with
higher emissions continuing through
2050
Used in as a Ref blend and in foam; Emissions due to
leakage and disposal
HFC-143
Not included in VM 1999
NA
HFC-152
Higher emissions in VM4.4
HFC use has grown significantly
CFC-114
Relatively close
CFC-114 used in chillers, foams, and aerosols. Not
completely phased out of MDI aerosol use until 2014
CFC-115
Higher emissions in VM4.4
Refrigerant blend in large equipment (transport, large
retail food, cold storage) with 20+ year lifetimes
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