APPENDIX F1

Inventory Comparison

2007/2008/2025

Summary

Bureau of Air Quality

Department of Environmental Protection
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Appendix F-1

Comparison of 2007, 2011 and 2025 Emission Inventories

To demonstrate maintenance of the PM2.5 NAAQS for the Pittsburgh-Beaver Valley Area, Pennsylvania 

must show that the future emissions of PM2.5 and its precursors will remain at levels that provide for 

maintenance of the PM2.5 NAAQS for at least 10 years, taking economic, population and travel growth 

into account. To make this demonstration, the Maintenance Plan compares the attainment year 

inventory, which represents the amount of emissions present during a time the area attained the PM2.5 

NAAQS, to projected inventories for future years.

The 2007 emission inventory is the attainment year inventory for the 1997 annual PM2.5 National 

Ambient Air Quality Standard (NAAQS) for the Pittsburgh-Beaver Valley Area. The 2011 emission 

inventory is the attainment year inventory for the 2006 24-hour PM2.5 NAAQS for the Pittsburgh-Beaver 

Valley Area. 

The 2007, 2017 and 2025 emission inventories were developed for MARAMA in a regional effort that 

Pennsylvania participated in to refine the emissions inventory and to compile a regional emissions

inventory. The 2017 and 2025 emission inventories were generated by applying anticipated growth and 

control factors to the 2007 emission inventory. See Appendix C for detailed inventory methodology 

information for 2007, 2017 and 2025 emission inventories. 

The 2007 and 2011 emission inventories were compared to demonstrate that it is a conservative

approach to compare the 2011 emission inventory to the future year inventories for 2017 and 2025 that 

were projected from the 2007 inventory. The comparison is based on the 2011 National Emissions 

Inventory (NEI) Version 2 for point, area and nonroad sources. To improve consistency with the 2007 

MARAMA inventory, the 2011 area source inventory excludes NOx and VOC emissions from biogenic 

sources and natural gas development activities. Also for consistency with the 2007 inventory, emissions 

from marine vessels, airports and railroads were moved from the area source category to the nonroad 

category. Emissions for the highway vehicle sector for 2011 were generated using the MOVES model. A 

detailed methodology description for the MOVES model is available in Appendix D of the Maintenance 

Plan.

A summary of the 2007 and 2011 emission inventories is displayed in Table 1. The inventory analysis 

shows that the 2011 emissions are lower than 2007 emissions for all pollutants, except ammonia (NH3) 

in the Pittsburgh-Beaver Valley PM2.5 nonattainment area. NH3 emissions increase slightly by 127 tons 

(3.2%), which is not a concern in this analysis because the increase is small and ammonia emissions are 

small compared to emissions of PM2.5, SO2, NOx and VOC in the Pittsburgh-Beaver Valley Area.

Because the 2011 emissions inventory is lower than the 2007 emissions inventory, lower emissions in 

2017 and 2025 would be estimated if projected from the 2011 emissions inventory. It is therefore a 

conservative approach to compare the 2011 attainment year emissions to the future year inventories 

for 2017 and 2025 projected from the 2007 emissions inventory.
The inventory analysis shows that a decreasing trend in emissions is anticipated through 2025 from both 

the 2007 and 2011 inventory base years. Therefore, both the 2007 and 2011 emission inventories 

satisfy the maintenance demonstration criteria provided in EPA guidance that a state may demonstrate 

maintenance of a NAAQS by showing that future projected emissions are less than or equal to the 

attainment year. ((See, EPA, “Procedures for Processing Requests to Redesignate Areas to Attainment,” 

John Calcagni (September 4, 1992) (Calcagni Memo)).

Table 1 - Comparison of 2007, 2011 and 2025 Emission Inventories for the Pittsburgh-Beaver Valley 

PM2.5 Nonattainment Area

2007 PM2.5 SO2 NOX VOC NH3

Point 8,913 438,716 92,750 3,186 584

Area 6,392 12,817 7,946 28,991 2,474

Highway Vehicle 1,692 378 49,052 20,194 858

Nonroad 1,151 694 21,175 10,834 16

2007 TOTAL 18,148 452,605 170,923 63,205 3,932

2011 PM2.5 SO2 NOX VOC NH3

Point - 2011 NEIv2 7,287 122,541 80,746 3,333 322

Area - 2011 NEIv2 7,133 3,528 7,013 22,859 3,106

Highway Vehicle - PA MOVES 967 149 29,184 14,813 624

Nonroad - 2011 NEIv2 877 92 13,592 8,129 13

2011 TOTAL 16,264 126,310 130,536 49,135 4,064

2025 PM2.5 SO2 NOX VOC NH3

Point 8,671 93,679 90,754 3,148 596

Area 5,720 10,302 7,969 26,030 2,610

Highway Vehicle 467 118 9,735 5,125 453

Nonroad 540 106 9,805 6,137 19

2025 TOTAL 15,398 104,205 118,263 40,440 3,678

PM2.5 SO2 NOX VOC NH3

Difference Between 2007 and 2011 -1,884 -326,295 -40,387 -14,070 132

% Change -10.4 -72.1 -23.6 -22.3 3.4
APPENDIX F2

Inventory Comparison

2007/2008/2025

Emissions Inventory Data

(Provided in Electronic Form Only)

Bureau of Air Quality

Department of Environmental Protection
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Comparison of 2007 and 2011 Emission Inventories

Pittsburgh‐Beaver Valley PM2.5 Nonattainment Area

2007 PM2.5 SO2 NOX VOC NH3

Point 8,913 438,716 92,750 3,186 584

Area 6,392 12,817 7,946 28,991 2,474

Highway Vehicle 1,692 378 49,052 20,194 858

Nonroad 1,151 694 21,175 10,834 16

2007 TOTAL 18,148 452,605 170,923 63,205 3,932

2011 PM2.5 SO2 NOX VOC NH3

Point ‐ 2011 NEIv2 7,287 122,541 80,746 3,333 322

Area ‐ 2011 NEIv2 7,133 3,528 7,013 22,859 3,106

Highway Vehicle ‐ PA MOVES 967 149 29,184 14,813 624

Nonroad ‐ 2011 NEIv2 877 92 13,592 8,129 13

2011 TOTAL 16,264 126,310 130,536 49,135 4,064

2025 PM2.5 SO2 NOX VOC NH3

Point 8,671 93,679 90,754 3,148 596

Area 5,720 10,302 7,969 26,030 2,610

Highway Vehicle 467 118 9,735 5,125 453

Nonroad 540 106 9,805 6,137 19

2025 TOTAL 15,398 104,205 118,263 40,440 3,678

PM2.5 SO2 NOX VOC NH3

Difference Between 2007 and 2011 ‐1,884 ‐326,295 ‐40,387 ‐14,070 132

% Change ‐10.4 ‐72.1 ‐23.6 ‐22.3 3.4