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

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

3 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 Definitions

4 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

5 QA/QC Levels 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 From US EPA’s Emission Inventory Improvement Program (EIIP) Vol. 6, page 2.1-5

6 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

7 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

8 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

9 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!

10 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 QC: What is included?

11 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 QC: What is included? (cont.)

12 Unit Example Asks for data in units of 1000 gallons

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

14 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 QC: How to track it

15 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 QC Methods: Reality Checks

16 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 QC Methods: Peer Review

17 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 QC Methods: Replication of Calculations

18 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) QC Methods: Computerized Checks

19 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

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

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

22 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

23 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 Typical Errors in EIs

24 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

25 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 QC Documentation

26 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.

27 Are You Hungry For More? Excellent resource and source for some of this presentation material EIIP Volume 6: Quality Assurance/Quality Control - ort/volume06/index.html ort/volume06/index.html

28 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 through 1.6-7)EIIP Volume 3, Chapter 1: Introduction to Area Source Emission Inventory Development Answer questions in exercise answers to instructors