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EMISSIONS INVENTORY BASE YEAR FOR NOx and VOC FOR THE BATON ROUGE 

NONATTAINMENT AREA UNDER THE 2008 EIGHT-HOUR OZONE NAAQS

This document provides a technical review of a revision to the Louisiana State Implementation 

Plan (SIP) to meet Clean Air Act (CAA) Base Year Emission Inventory (EI) for the Baton Rouge 

Nonattainment Area (BRNA) under Clean Air Act section 182(a)(1) and 40 CFR 51.1115 for the 2008 

eight-hour ozone standards submitted by the Louisiana Department of Environmental Quality (LDEQ) on 

May 2, 2015. 

A. General Requirements 

Under the CAA sections 172(c)(3) and 182 (a)(1), states are required to submit emissions inventory 

(EI) information for all relevant sources for areas that are designated nonattainment for any of the National 

Ambient Air Quality Standards (NAAQS). On March 27, 2008, the United States Environmental Protection 

Agency (EPA) lowered the primary and secondary eight-hour ozone NAAQS to 0.075 parts per million 

(ppm) (73 FR 16436).

1 On May 21, 2012, the EPA published in the Federal Register (77 FR 30088) final 

designations for the 2008 Ozone standard. The BRNA consists of five parishes: Ascension, East Baton 

Rouge, Iberville, Livingston, and West Baton Rouge and was designated and classified as marginal 

nonattainment. The effective date of the final rule is July 20, 2012.

The EPA published the final 2008 ozone standard SIP requirements rule on March 6, 2015, which 

specified that states use 2011 as a base year to address EI requirements. (80 FR 12264). The nonattainment 

area base year EI emission is due no later than 24 months from the July 20, 2012 effective date. Id. An 

emissions inventory is an estimation of actual emissions of air pollutants in an area. Volatile organic 

compounds (VOCs) and oxides of nitrogen (NOx) are known as “ozone precursors”, as they react with 

oxygen and sunlight to form ozone. Motor vehicle exhaust, industrial emissions, gasoline vapors and 

chemical solvents emit NOx and VOCs. Controlling sources of NOx and VOC emissions can lower ozone 

levels in the ambient air. Thus, the emissions inventory for an ozone nonattainment area contains VOC and 

NOx emissions. The EIs provide data for a variety of air quality planning tasks including: establishing 

baseline emission levels, calculating federally required emission reduction targets, emission inputs into air 

quality simulation models, and tracking emissions over time. The total EI of VOC and NOx for an area are 

summarized from the estimates developed for four general classes of anthropogenic emissions sources: 

stationary sources; on-road mobile sources; and off-road mobile sources, area, mobile, and biogenic.

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B. Background

The majority of NOx emissions in the BRNA come from point sources. Point sources are large, stationary, 

emissions sources that release pollutants into the atmosphere. These sources could include refineries, 

chemical plants, bulk terminals, and utilities. Area sources, also called nonpoint sources, are the second 

largest contributor of NOx emissions, and are the largest contributor for VOC emissions. Area sources 

 1 We refer to this NAAQS as the 2008 ozone NAAQS or standard.

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Biogenic emissions are produced by living organisms and are typically not included in the base year emission 

inventories, but are considered in ozone modeling analyses, which must consider all emissions in a modeled area.
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consist of small-scale industrial, commercial, and residential sources that use materials or perform 

processes that generate emissions.

Eight-Hour Ozone Standard in BRNA

In July 1997, the EPA announced a revised NAAQS for ground-level ozone. (62 FR 38856, July 18, 1997). 

The EPA phased out and replaced the previous one-hour standard with an eight-hour standard set at 0.08 

ppm to protect the public health against longer exposure to this air pollutant. Id. The eight-hour ozone 

standard became effective on September 16, 1997. Id.

In a final rule signed April 15, 2004, EPA designated the BRNA as nonattainment and classified the area as 

marginal (69 FR 23858, April 30, 2004). This rule was effective June 15, 2004 and the BRNA was required 

to reach attainment by June 15, 2007.

The BRNA monitored attainment with the 1997 8-Hour NAAQS for ozone on December 31, 2008. 

Accordingly, LDEQ submitted a request for determination of attainment based on EPA’s Clean Data 

Regulation (40 CFR 51.918). On June 25, 2010, EPA proposed a determination of attainment of the 1997 

8-Hour Ozone standard for the BRNA. (75 FR 36316). A final determination was published in the Federal 

Register on September 9, 2010. (75 FR 54778).

At the request of the state, EPA proposed to re-designate the BRNA to attainment on August 30, 2011. (76 

FR 53852). The request was published for final approval on November 30, 2011. (76 FR 74000).

On July 11, 2007, EPA proposed the second NAAQS revision for ozone. (72 FR 37818). In the final rule 

published on March 27, 2008, the primary and secondary standards were set at 0.075 ppm. (73 FR 

16436).Effective July 20, 2012, Louisiana was designated nonattainment and classified as marginal when 

nonattainment designations for the 2008 ozone NAAQS were published in the Federal Register on May 21, 

2012. As such, the state was required to meet an attainment date of December 31, 2015. (77 FR 30087).

As of December 31, 2013, and based upon complete, quality assured, certified ambient air monitoring data 

that showed the area monitored attainment for the 2008 8-hour Ozone NAAQS during the 2011-2013 

monitoring period, the Department submitted a request for determination of attainment based on US EPA’s 

Clean Data Policy (www.epa.gov/ttn/oarpg/t1/memoranda/clean15.pdf).

3 In concurrence, US EPA 

proposed and granted final approval on April 15, 2014. (79 FR 21139, 79 FR 21178). On May 21, 2012, 

BRNA was designated as a marginal nonattainment area with monitored design values ranging from 0.077 

to 0.083 ppm based on ozone monitoring data from the period of 2006 to 2008. (77 FR 30088). EPA later 

determined that the area and 16 other marginal nonattainment areas attained the NAAQS by the attainment 

deadline (81 FR 26697, May 4, 2016).

C. EPA’s Analysis 

The EPA reviewed the Louisiana’s submittal for consistency with the EPA regulations. The following is a 

summary of the analysis based on the information provided by Louisiana.

The 2011 Base Year Inventory is the starting point for calculating the reductions necessary to meet the

requirements of the CAA. Sections 172 (c)(3) and 182(b)(1) of the CAA require that nonattainment plan 

provisions include an inventory of actual emissions from all sources of relevant pollutants in the 

nonattainment area. On August 28, 2015, the LDEQ submitted the 2011 base year inventory to the EPA as 

part of the LDEQ’s draft proposal for re-designation to attainment for the 2008 eight hour Ozone NAAQS 

 3 At the time EPA had not finalized the Clean Data Regulation for the 2008 ozone NAAQS at 40 CFR 51.1118.
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for the 5-parish Baton Rouge Nonattainment area. In response to comments received from the EPA, Region 

6, the LDEQ submitted a revised proposal to EPA in a letter dated March 18, 2016. The LDEQ’s revised 

proposal refined the point and nonpoint source growth projections originally presented in the proposal. 

LDEQ then submitted the final 2011 base year inventory as part of the BRNA re-designation request and 

maintenance plan in a letter dated May 2, 2016.

The EPA reviewed the 2011 base year inventory and determined that it was developed in accordance with 

EPA guidelines. The inventory includes all area, point, non-road mobile, and on-road mobile source 

emissions in the BRNA. The inventory also includes a description of the methods used to estimate 

emissions: 

Point Source Emissions: Industrial sources are required to submit emissions data to the LDEQ annually and 

certify that the data reported is accurate to the best of their knowledge. For the purpose of EI, point sources 

that emit 100 tons or more per year of a criteria pollutant meet the reporting threshold (40 CFR 51 Subpart 

A). In the BRNA all sources that emit 25 tons of NOx or 10 tons of VOC are required to report. Each of the 

facilities meeting these emissions criteria submit complete EI reports which contain site-specific data in 

conformance with USEPA guidance for ozone maintenance areas. A list of the 230 point sources located in 

the BRNA as of May 15, 2015, is included in Appendix G of the state submittal. 

The reporting requirements for the nonattainment areas are in accordance with those of the CAA and LAC 

33:III.918 and 919 – Recordkeeping and Annual Reporting and Emissions Inventory. Emissions data 

provided by the facilities are estimates of actual emissions for the facility during the previous calendar year. 

Actual measurement with continuous emissions monitoring systems (CEMS) or approved stack testing 

shall be used for reporting of emissions from an emissions point when such data exists. In absence of 

CEMS or stack test data, emissions are calculated using methods found in the most recent editions as of 

December 31 of the current reporting year, of US EPA’s compilation of Air Pollution Emission Factors 

(AP-42), calculations published in engineering journals, and/or US EPA or department approved estimation 

methodologies. 

LDEQ submits annual updates to USEPA for point sources and triennial updates for all sources in 

accordance with 40 CFR Part 51 Subpart A – Air Emissions Reporting Requirements (AERR).

Non-Point (Area) Source Emissions: Area sources are represented as many small, individually unidentified 

points of air pollution emissions within a specified geographical area. These small-scale industrial, 

commercial, and residential sources that generate emissions are too numerous or too small to be addressed 

individually and include but not limited to, activities such as fuel combustion, dry cleaning bakeries, 

graphic arts, auto refinishing, product storage, agriculture activities, and consumer product usage. Emission 

factors used to estimated emissions are developed and applied for the aggregate source categories. LDEQ 

developed the 2011 area source emission inventory in according to the AERR reporting requirements, using 

a combination of methodologies and data: EPA-generated EIs, LDEQ-contracted projects, LDEQ staff 

projects. EPA developed EIs for states for use for many source categories as part of the NEI. For some 

source categories, the LDEQ developed state-specific emissions estimates by acquiring state-specific 

activity data and applying appropriate emissions factors. These source categories include, but are not 

limited to: storage tanks, structural fires, dry cleaners, automobile fires and oil and gas. 

We have reviewed these approaches and have determined that they are acceptable.
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Non-road Emissions Inventory Non-road mobile sources are often included as nonpoint sources because of 

the number and size of sources. Non-road mobile sources include, but are not limited to, railroad 

locomotives, aircraft and airport support equipment, commercial and recreational marine vessels,

construction equipment, agricultural equipment, commercial and residential lawn equipment, and 

recreational vehicles. We find the approach and methodology used by the LDEQ acceptable. 

On-road Emission Inventory On-road emission sources consist of light and heavy duty, gasoline and diesel 

automobiles and trucks that travel primarily on public highways. On-road mobile emissions are pollutants 

emitted from vehicles during driving operations and while parked. Emissions from the refueling of motor 

vehicles at service stations, Stage 2 refueling are included under non-point source emissions. One-road 

mobile emissions estimates within the nonattainment area were developed based on parish-specific inputs 

provided by the Department of Transportations and Development and the Capitol Region Planning 

commission. The EPA reviewed the on-road emission estimates approach and methodology and determined 

that they are acceptable. 

Louisiana emissions for the 2011 were extracted from the US EPA 2011 National Emissions Inventory 

(NEI), version 2. The Table below summarizes the 2011 NOx and VOC emission totals by source category 

which comprises the baseline inventory for the BRNA. The 2011 base year emissions data for the BRNA 

are provided in Table 1 below.

Table 1- 5-Parish BRNA 2011Base Year Emissions Inventory

Nonpoint

NOx

Non-road On-road Point

Emission 

Total

Ascension 3.1 5.5 5.2 20.9 34.7

East Baton 

Rouge

7.8 8.6 18.6 24.8 59.9

Iberville 2.9 7.7 2.7 25.6 38.9

Livingston 1.5 1.0 8.4 0.2 11.0

West Baton 

Rouge

1.9 4.5 3.5 2.7 12.5

BRNA Total 17.1 27.3 38.4 74.2 157.0

Nonpoint Non-road

VOC

On-road Point

Emission 

Total

Ascension 20.7 1.0 2.8 8.5 32.9

East Baton 

Rouge

30.8 3.4 10.2 15.1 59.4

Iberville 18.5 0.9 1.1 7.2 27.7

Livingston 8.5 2.1 4.1 0.9 15.7

West Baton 

Rouge

4.1 1.2 1.0 2.0 8.3

BRNA Total 82.6 8.7 19.2 33.6 144.0
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D. Summary and Recommendations:

Pursuant to Title 40 Code of Federal Regulations Part 51.102 and after proper notice, the LDEQ conducted 

a public hearing to consider the EI revision to the SIP. Proper notice included prominent advertisement in 

the areas affected at least 30 days prior to the date of the hearing. The Department has included revisions to 

the document based on comment and review. Public notice of this revision was published on March 20, 

2016, in the Louisiana Register (Vol. 41, No. 6 page 1163). The comment period ended on April 29, 2016; 

no adverse comments were received. A copy of the notice and comments is included in Appendix B.5 of 

LDEQ’s submittal. 

The LDEQ has used acceptable techniques and methodologies to develop the 2011-base year emission 

inventories for the 2008 ozone NAAQS for the BRNA to satisfy sections 172 and 182 of the CAA. 

Therefore we recommend approval of the Louisiana State Implementation Plan (SIP) revisions to 

meet the CAA EI reporting requirements for the BRNA under the 2008 ozone NAAQS, submitted by the 

LDEQ on May 2, 2016.