Air Monitoring Update

1. Air Monitoring Update Spring Region 4 Air Directors’ Meeting Atlanta, Georgia May 22, 2019

2. 5-Year Air Monitoring Network Assessments • Required by 40 CFR Part 58.10(d) • Assessments provide an opportunity to: • evaluate how your monitoring networks meet your area’s needs (and meet federal requirements), • plan for changes over the next five years, and • prioritize your resources • R4 will provide guidance on what to include in the assessments as well as web-based tools to help agencies conduct them • Last assessments were completed in 2015 and R4 provided comments on them • Assessment and network plan can be combined into one document Source: LADCO

3. 2018 Data Certification • 2018 data certifications were due May 1. • R4 has received most of the certifications and has already acted on/concurred on many of them. • Several agencies have notified R4 that their certifications will be forthcoming. • R4’s goal is to act on all of the submittals by July 1, 2019. • Please let us know if you have questions.

4. Exceptional Events Guidance Documents • High Wind Event Guidance • https://www.epa.gov/air-quality-analysis/guidance-preparation-demonstrations-support-requests-exclude-ambient-air • Clarification Memo on Data Modification • aka, Additional Methods, Determinations, and Analyses to Modify Air Quality Data Beyond Exceptional Events (or “Alternate Paths Guidance”) • https://www.epa.gov/air-quality-analysis/clarification-memo-additional-methods-determinations-and-analyses-modify-air • Both documents were signed on April 4, 2019

5. Exceptional Events Guidance Documents • Clarification Memo on Data Modification • Monitoring data exclusion, selection, or adjustment may be considered for the following types of determinations/analyses NOT covered by the Exceptional Events Rule: • Certain Part 51, Appendix W modeling analyses • Demonstrating compliance under the PSD permitting program • Estimating base, future year DVs for O3 and PM2.5 SIP attainment demos • Determining whether a SIP satisfies an interstate transport requirement • Analyzing PM “hot spots” for transportation conformity determinations • Selecting data for tracking visibility on 20% clearest and most impaired days, as required by the Regional Haze Rule • Analyzing NAAQS Limited Maintenance Plan SIP submissions and implementation

6. Exceptional Events Guidance Documents • Clarification Memo on Data Modification (cont’d) • Also clarifies regulatory determinations for which there is NO mechanism for data exclusion, selection, or adjustment, including: • monitor siting, sampling frequency, minimum number, or other monitoring requirements for an area • monitoring data completeness

7. Development of PM2.5 Continuous Networks • R4 agencies embracing continuous technologies: • MDEQ & TDEC have fully implemented and are meeting all the requirements • GEPD will be transitioning over several years as their budget allows • Several agencies are still evaluating continuous method monitors • Please work with us to make sure QA collocation requirements are met. • The first collocated sampler MUST be an FRM—can’t get rid of FRMs completely • Most R4 agencies are now using contract labs to analyze data from their remaining FRMs