Emission Inventory Quality Assurance Quality Control QA QC Melinda Ronca-Battista

Emission Inventory Quality Assurance/Quality Control (QA/QC) Melinda Ronca-Battista ITEP/TAMS Center

Homework Discussion • Are there any questions on entering nonpoint data or point data into TEISS? 2

Definitions • Quality Control (QC) • • Documenting data sources Rechecking calculations Accuracy checks Use of approved standardized procedures for emissions calculations • Quality Assurance (QA) • External review and audit procedures by a third party 3

QA/QC: Where to Start? • Prepare QAPP that answers • What are you going to report in EI? • What will you use the EI data for? • How are you going to review the data? See template QAPP • Potential uses of EI data will define minimum level of QA/QC 4

QA/QC Levels From US EPA’s Emission Inventory Improvement Program (EIIP) Vol. 6, page 2. 1 -5 • Level 1 – supports enforcement, compliance, or litigation • Level 2 – supports strategic decision making • Level 3 – general assessment or research • Level 4 – Inventory compiled entirely from previously published data or other inventories 5

Data Quality Objectives (DQOs) • DQOs • Broad statement on how “good” or “true” your EI results will be • EI ESTIMATES emissions. You can’t know exact “truth” about quantity or type of pollutants from a given source 6

DQOs: Examples • EI DQO for Accuracy • 100% of data transcribed from paper forms to TEISS will be verified • EPA methods used to estimate emissions, ensure estimates as close to “truth” as possible • Track Accuracy Checks with TEISS QA/QC functions 7

DQOs: Examples • DQO for Completeness • 100% of largest point sources of PM included in EI • DQO for Comparability: • Emissions calculated represent “truth” on your reservation • Emissions comparable to similar sources or areas 8

DQOs are set, now what’s the plan? • QC should be included in each EI task • QC for data collection • QC for calculations • QC for choosing estimation methods • Allocate at least 10% of resources for QA activities • Don’t wait until the end! 9

QC: What is included? • Check transcription of data during inventory preparation and reporting • Transcription of data from raw data collection sheets into electronic spreadsheets or TEISS calculators • Transcription of data results from TEISS summary tables to EI report 10

QC: What is included? (cont. ) • Check calculations • Including calculation of throughput, if necessary • If not calculating emissions with TEISS calculator, check that throughput multiplied by EF equals emissions • Verify that unit conversions are correct • Verify that units of your data match units TEISS or equation asks for 11

Unit Example Asks for data in units of 1000 gallons 12

QC: What is included? (cont. ) • Verify you’ve documented all data sources • Completeness checks • Consistency checks • Double counting • Reasonableness 13

QC: How to track it • Keep a file for each source • Use checklist to monitor person and date for • • • Data collection Data calculations Evaluation of data reasonableness Evaluation of data completeness Data coding and recording Data tracking 14

QC Methods: Reality Checks • Most commonly used • Is this number reasonable? Does it make sense? • Never use the reality check as the sole criterion of quality • Find data for similar sources on EPA’s EIS Gateway system 15

QC Methods: Peer Review • Independent review of calculations, assumptions, and/or documentation by person with moderate to high level of technical experience • QA is a form of peer review • Can also be included as part of QC 16

QC Methods: Replication of Calculations • Most reliable way to detect computational errors • General rule, minimum of 10% of calculations checked, depending on • Complexity of calculations • Inventory DQOs • Rate of errors encountered 17

QC Methods: Computerized Checks • Automated data checks can be • Built-in functions of databases, models, or spreadsheets, or stand-alone programs • Automate to • Check for data format errors (like Export to NEI component of TEISS) • Conduct range checks • Provide look-up tables to define permissible entries (like TEISS selection boxes) 18

TEISS needs a Human Touch • TEISS is an excellent tool; however, it needs your guidance • Be familiar with emission methodologies on which TEISS calculators are based 19

Finding Calculator Methodology • Scroll down on summary screen to get to Reference and Online Link 20

Why Review the Methodology? • What do I select here? 21

Methodology Has Answers • Methodology: used to calculate emissions for 4 different “station operations” (in most cases) • Underground tank filling • Underground tank breathing • Vehicle refueling displacement losses • Vehicle refueling spillage • Each operation should be included as a different Process in TEISS • If using an EPA model to calculate onroad emissions, make sure vehicle refueling emissions are not double counted 22

Typical Errors in EIs • • Missing or duplicate facilities Improper facility locations Missing operating or technical data Erroneous technical data Double counting Errors in calculations Data entry and transposition errors; data coding errors 23

Most Typical QC Error Letting it slide • Make sure to include time for QA/QC • Pressure to gather data and “get it done” can harm documentation & verification • Putting it off to project’s end 24

QC Documentation • Ensure final written compilation of data accurately reflects inventory effort • Support QA assessments of inventory • Ensure reproducibility of inventory estimates • Enable inventory user or reviewer to assess quality of emission estimates and identify data references • Foundation for future inventories 25

What about QA? • Independent review by third party, ITEP for example • Checks effectiveness of your QC • Allocate 10% of project resources to QA • Again, don’t wait until the end • QA person checks a fraction of data entry, calculations, documentation, etc. 26

Are You Hungry For More? • Excellent resource and source for some of this presentation material • EIIP Volume 6: Quality Assurance/Quality Control http: //www. epa. gov/ttn/chief/eiip/techrep ort/volume 06/index. html 27

Homework due in 5 days: • Read EIIP Volume 3, Chapter 1: Introduction to Area Source Emission Inventory Development, Sections 6. 1 and 6. 2 (pages 1. 6 -1 through 1. 6 -7) • Answer questions in exercise • Email answers to instructors 28