Improving the Emissions Inventory Brad Toups, Manager Industrial Emissions Assessment August 12, 2004 Regulatory Forum

TexAQS 2000 The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including: –Better understanding of plume characteristics…

B A NE to E flow all day Wind Direction

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TexAQS 2000 The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including: –Better understanding of plume characteristics –Better understanding about NOx and VOCs on Ozone Formation…

Ozone Formation Ozone is produced faster and yields more in Houston than in other cities. –The rapid formation and high ozone yield occur in the industrial plumes downwind of petrochemical facilities. –Formation rates and yield downwind of the power plants and the city core are comparable to other cities.

VOC Measurements The VOC concentrations in Houston are very different from other cities. » –Ethylene concentrations in Houston are much higher than in other cities. –Ethylene is a highly reactive VOC produced in petrochemical facilities as an intermediate product in plastics production. –Other highly reactive VOCs such as Ethylene, propylene, Butene and Butadiene are also produced in Houston.

Ethylene Distributions – Log Scale The Maximum ethylene levels are an order of magnitude or more higher in Houston The ethylene distribution in Houston is approximately log-normal, suggesting continuous emissions. Ethylene emissions are definitely not Bimodal; there is no evidence to suggest two separable populations (upsets) Parrish, 2002

TexAQS 2000 The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including: –A better understanding of plume characteristics –A better understanding about NOx and VOCs on ozone formation –That there is more VOC in the atmosphere than can be accounted for in the Inventory…

Inferred vs Reported Olefin Emissions Based upon Auto GC Data Estes Ratio

VOC Emissions Actual VOC emissions are much greater than reported in the Emissions Inventory –Aircraft measurements of VOC and NOx indicate that VOC concentrations are up to an order of magnitude larger than inventory reported emissions. –High VOC concentrations occur 40-60% of the time in industrial areas, indicating that these VOC releases are not rare occurrences, but relatively frequent events. –Either upsets are much more frequent than reported, or there are far more leaks than currently estimated.

TexAQS 2000 The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including: –A better understanding of plume characteristics –A better understanding about NOx and VOCs on ozone formation –That there is more VOC in the atmosphere than can be accounted for in the Inventory

Adjusted VOCs Generate More Ozone and Improve Model Performance Box model with adjusted ratios of ethylene and propylene to NOx reproduces the ozone measured by the aircraft quite well Trainer, 2001

Why do we need to improve the Emissions Inventory? We need to put the correct meteorological data and correct emissions data into the model So the model can give us the right answers for the right reasons So we can develop effective policies to control ozone

Inventory Improvement Goals Accuracy and Completeness Correct census of sources Location and physical characteristics of the Facility, Control Device, Emission Point Chemical speciation under all conditions Chemical quantification under all conditions

Complete Census Working towards a database to capture allowable emissions from all authorization mechanisms

Physical Characteristics of FIN, CIN, EPN

Physical Characteristics (con’t)

Before aerial photo

After Aerial Photo

Inferred vs Reported Olefin Emissions Based upon Auto GC Data Estes Ratio

Inventory Improvement Goals Accuracy and Completeness Correct census of sources Location and physical characteristics of the Facility, Control Device, Emission Point Chemical speciation under all conditions Chemical quantification under all conditions

Chemical speciation under all conditions Developing Statistical Tools to: – identify mix and proporation of contaminants per SCC Matching Permit Representations with respect to speciation We have and continue to require the most accurate, up to date assessment techniques Integrating Emissions Events information into EI reviews

Inventory Improvement Goals Accuracy and Completeness Correct census of sources Location and physical characteristics of the Facility, Control Device, Emission Point Chemical speciation under all conditions Chemical quantification under all conditions

Particularly with VOCs, –Some VOC components (like ethylene) are highly reactive, others contribute less to ozone formation –We need measurements of the composition of the VOC emissions from various industrial processes. Will continue to challenge inappropriate use of emissions factors when better information is available Will insist on consistency with EI Guidelines

Potentially Underreported Sources Focus on VOCs: –Fugatives –Cooling Towers –Flares –Wastewater Systems

Risk Based Approach Statistical Tool development –Will continue to develop more tools to identify discrepancies in reported data Risk Based closer review of selected sites Appropriate enforcement to encourage Responsible Official to assure reported emissions are accurate and complete

Weinheimer and Flocke Overall NOx Reduction EPA Standard

Emissions Inventory Improvements Benefits: –Form a solid foundation for air quality planning –Help to characterize rule effectiveness for controlling emissions –Provide increased assurance to the Public about sources of emissions and emissions trends –Provide a sound basis for emissions fee assessments –Reduce reliance on ‘factors’ in modeling

Resources Emissions Inventory Rules and Guidance – Emissions Inventory Helpline – TexAQS Study Information – lerated.htm