St. John, Virgin Islands 

2002 Regional Haze Base Year Modeling Inventory SIP  

Technical Support Documentation

June 19, 2012



	PREFACE

This document is to support EPA's approval of a revision to the Virgin
Islands’ State Implementation Plan (SIP) which pertains to the
following: 

Where applicable, 2002 modeling base year inventory annual emissions for
PM2.5, NOx and SO2 for St. John, Virgin Island (VI) area.  Among the
topics discussed below are the recent history and criteria for approval
and EPA’s final recommendations.	

	BACKGROUND 

On November 18, 2002, EPA designated the 2002 base year inventory as the
inventory for SIP planning process to address the pollutants for the
eight hour-ozone, PM2.5 and CO national ambient air quality standard. 
Identifying the base year gives certainty to States, and the selection
of 2002 harmonized the date for EPA’s Consolidated Emissions Reporting
rule (See 67 FR 39602) dated June 10, 2002.) that requires submission of
the ozone, PM2.5 and CO emission inventories every three years; 2002 is
one of the required years for such updates.  These requirements allow
the EPA, based on the state’s progress in reducing emissions, to
periodically reassess its policies and air quality standards and revise
them as necessary.  Most important, the 2002 ozone, new PM2.5 and CO
inventories will be used to develop and assess new control strategies
that the states will need to submit in their attainment demonstration
SIPs for the new national ambient air quality standards for ozone, PM2.5
and CO.  The base year inventory may also serve as part of statewide
inventories for purposes of regional modeling in transport areas.  The
base year inventory plays an important role in modeling demonstrations
for areas classified as nonattainment and outside transport regions. 
For the reasons stated above, ideally EPA would therefore emphasize the
importance and benefits of developing a comprehensive, current, and
accurate 2002 ozone and PM2.5 emission inventories.

	CRITERIA FOR APPROVAL

There are general and specific components of an acceptable emissions
inventory.  In general, the State must submit a revision to its SIP and
the emission inventory must meet the minimum requirements for reporting
by source category.  Specifically, the source requirements are detailed
below.

The Level I and II review process is used to determine that all
components of the base year inventory are present.  The review also
evaluates the level of supporting documentation provided by the State
and assesses whether the emissions were developed according to current
EPA or acceptable alternative guidance.  The data quality is also
evaluated. 

The Level III review process is outlined here and consists of 9 points
that the inventory must adequately address.  For a base year emission
inventory to be acceptable it must pass all of the following acceptance
criteria: 

Adequate documentation must be provided that enabled the reviewer to
determine the emission estimation procedures and the data sources used
to develop the inventory.

1.	Evidence that the inventory was quality assured by the state and its
implementation documented.

2.	The point source inventory must be complete.

3.	Point source emissions must have been prepared or calculated
according to the current EPA guidance.

4.	The area source inventory must be complete.

5.	The area source emissions must have been prepared or calculated
according to the current EPA guidance.

6.	Non-road mobile emissions were prepared according to current EPA
guidance for all of the source categories.

8.	The method (e.g., HPMS or a network transportation planning model)
used to develop VMT estimates must follow EPA guidance.  The VMT
development methods were adequately described and documented in the
inventory report.

9.	The MOBILE model must be correctly used to produce emission factors
for each of the vehicle classes.

	DETAILED ACTION AND EVALUATION

Drafts and final versions of the Emissions Inventory were provided to
Region 2 for the following documents and program area elements:

Where applicable, 2002 base year inventory annual PM2.5, NOx and SO2
emissions for the area.  See Tables 1-3 below.  This TSD contains a
detailed discussion and summary of the review conducted by EPA for,
where applicable, the 2002 base year inventory annual emissions for
PM2.5, NOx and SO2 the area.

	Details on How the Virgin Islands Satisfies Criteria 1 for the Quality
Assurance Plan

Quality Assurance Plan Implementation

The Quality Assurance (QA) plan was implemented for all portions of the
inventory.  The QA plan included a QA/Quality control (QC) program for
assessing data completeness and standard range checking.  Critical data
elements relative to the inventory sources were assessed for
completeness.  QA checks were performed relative to data collection and
analysis, and double counting of emissions from point, area and mobile
sources.  QA/QC checks were conducted to ensure accuracy of units, unit
conversions, transposition of figures, and calculations. 

The reader is referred to Chapter II of Development of the 2002 Regional
Haze Area, Point, Nonroad Mobile and Onroad Mobile Source Emission
Inventories for St. John, Virgin Islands, dated June 2010.  The QA plan
for the inventory was performed in accordance with EPA Guidance.1,2,3

	Details on How the Virgin Islands Satisfies Criteria 2 and 3 for the
Point Source Inventory

Point Source Inventory

St. John, VI inventory includes point sources PM2.5, NOx and SO2
emissions for the area..  The inventory report describes how point
source activity levels and their associated parameters are developed,
and how the data are used to calculate emission estimates.  The report
references document for activity level and emission factors used and
provides sample actual activity data and emissions factors.  Information
on how control efficiencies are applied and the associated sample
calculations with numerical values are provided.  Where applicable,
annual PM2.5, NOx and SO2 point source emissions are presented for the
area.  Plant summary information on detailed plant levels is included in
the inventory.  The reader is referred to Chapter III of Development of
the 2002 Regional Haze Area, Point, Nonroad Mobile and Onroad Mobile
Source Emission Inventories for St. John, Virgin Islands, dated June
2010.  Thus, the point inventory was developed in accordance with
section 5.3 of EPA Guidance.1,2,3

	Details on How The Virgin Islands Satisfies Criteria 4 and 5 for the
Area Source Inventory

Area Source Inventory

The inventory lists the source categories that are included in the area
source inventory. Area source emissions are presented on a source
category, county basis.  Where applicable, annual emissions are provided
for PM2.5, SO2 and NOx for the area. Inventory documentation includes
emissions factors, activity levels and sample calculations.  Referenced
information for the input values to equations is included.  Point source
contributions have been correctly factored out of the area source
category totals where appropriate.  Control efficiency and rule
penetration are correctly applied for source categories. The reader is
referred to Chapter IV of Development of the 2002 Regional Haze Area,
Point, Nonroad Mobile and Onroad Mobile Source Emission Inventories for
St. John, Virgin Islands, dated June 2010.  Thus, the area source
inventory was developed in accordance with EPA Guidance.1,2,3

	Details on How The Virgin Islands Satisfies Criteria 6 for Non Road
Mobile Source Inventory

Commercial Marine Vessel Emissions

Commercial marine vessel (CMV) emissions for PM2.5, NOx, and SO2 and NH3
are prepared by EPA contractor.  The inventory report relied on actual
operational data and then used local activity parameters.  From this
information, emission estimates are prepared based on estimated activity
by mode, engine power by vessel, time in mode..etc.  Where applicable,
annual emissions are provided for PM2.5, NOx, and SO2 for total combined
nonroad mobile sources for the areas.  CMV source emissions are
presented on a source category basis.

The reader is referred to Chapter V of Development of the 2002 Regional
Haze Area, Point, Nonroad Mobile and Onroad Mobile Source Emission
Inventories for St. John, Virgin Islands, dated June 2010. CMV source
emissions was developed in accordance with EPA Guidance.1, 2, 3

.

	Details on How The Virgin Islands Satisfies Criteria 8 and 9  for the
Onroad  Source Inventory

Onroad Mobile Source Inventory

The Virgin Islands’  mobile source inventory was developed by using
2002 annual vehicle miles traveled (VMT) inventory from a surrogate area
of Kauai, Hawaii by using VMT data from Kauai and population data from
Kauai and St. Johns, VI to develop VMT estimates by county, geographic
component (urban, small urban and rural) and functional classes.  

Mobile 6 model for PM2.5, NOx and SO2 was used to generate emission
factors for onroad vehicle emission estimates.  The report also explains
how Mobile 6 emission factors are used, in conjunction with VMT data, to
estimate mobile source emissions for the inventoried areas.  It provides
the sources for the key inputs into the Mobile model.  Key assumptions
are also included.  The methods used to determine on-road emission
estimates are explained in the EPA’s Documentation for the Onroad NEI
for Base Years 1970-2002, dated January 2004.  Where applicable, annual
emissions are provided for PM2.5, NOx and SO2 the area.  The breakdown
of annual emissions by highway vehicle classifications is included in
the inventory.  The inventory was developed in accordance with EPA
Guidance.1,2, 3

2018 Emissions Inventory

Unfortunately, not enough is known about possible growth on St. John to
use growth factors.

Growth of population and sources may be restricted, as a result of the
small size of the island and the large amount of land included in the
National Park.  There is not enough information available for the motor
vehicle fleet on St. John, and projections based on vehicle turnover may
be very different from reality in an isolated location such as St. John
and no interstate highways to bring outside traffic through.  Therefore,
no growth factors were applied to the area, nonroad mobile and onroad
mobile source inventories from base year 2002 to 2018.  See 2018
Modeling inventory below in Tables 1-3.



Table 1: Sulfur Oxides Emissions from Point, Area and Mobile Sources on
St. John, Virgin Islands (tons per year)

Source Sector	Baseline 2002	2018 (with measures for RPG)

Point	43.11	43.11

Area	0.05	0.05

Non-Road Mobile	17.89	17.89

On-Road Mobile	1.61	1.61

Marine Vessels	94.06	14.11

Total	  =SUM(ABOVE)  156.72 	  =SUM(above)  76.77 



Table 2: Nitrogen Oxide Emissions from Point, Area and Mobile Sources on
St. John, Virgin Islands (tons per year)

Source Sector	Baseline 2002	2018 (with measures for RPG)

Point	477.66	477.66

Area	3.69	3.69

Non-Road Mobile	2.07	2.07

On-Road Mobile	25.03	25.03

Marine Vessels	318.23	63.65

Total	  =SUM(ABOVE)  826.68 	  =SUM(above)  572.1 



Table 3: Direct Emissions of Particulate Matter from Point, Area and
Mobile Sources on St. John, Virgin Islands (tons per year)

Source Sector	Baseline 2002	2018 (with measures for RPG)

Point	34.33	34.33

Area	38.32	38.32

Non-Road Mobile	1.93	1.93

On-Road Mobile	0.73	0.73

Marine Vessels	8.57	1.28

Total	  =SUM(ABOVE)  83.88 	  =SUM(above)  76.59 





Table 5: Emissions from HOVENSA (in tons per year)

	Sulfur Oxides	Nitrogen Oxides	Particulate Matter

HOVENSA Base 2002	12,778	26,362	2,207

HOVENSA Future 2018	9,318	21,331	2,192



Conclusion

Virgin Islands has a SIP that demonstrates the requirements for emission
inventory measures and reporting are adequately met.  To comply with the
emission inventory requirements, the State must submit a complete
inventory containing an implemented Quality Assurance Plan, point, area,
on-road, and non-road mobile source data, and accompanying support
documentation.

Recommendation

EPA is approving this SIP submittal because it meets the essential
reporting requirements for an Emissions Inventory.  

 Emission Inventory Guidance Documents

1Emission Inventory Guidance for Implementation of ozone and Particulate
Matter NAAQS and Regional Haze Regulation, September 2005

2Example Documentation Report for 1990 Base Year Ozone and Carbon
Monoxide State Implementation Plan Emission Inventories, March 1992

3Guidance on the Use of Models and Other Analyses
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