IMPERIAL COUNTY AIR POLLUTION CONTROL DISTRICT https://en.wikipedia.org/wiki/Coyote_Mountains#/media/File:Coyote_Mountains.png May 6, 2017 Exceptional Event Documentation For the Imperial County PM10 Nonattainment Area An exceedance of the National Ambient Air Quality Standard (NAAQS) for PM10 at the Brawley, Calexico, El Centro, Niland and Westmorland monitor in California on May 6, 2017 May 6, 2017 Exceptional Event, Imperial County Table of Contents TABLE OF CONTENTS SECTION PAGE I Introduction .................................................................................................................................. 1 I.1 Public Notification [40 CFR §50.14(c)(1)] .............................................................. 3 I.2 Initial Notification of Potential Exceptional Event (INPEE) (40 CFR §50.14 (c)(2)) ................................................................................................... 3 I.3 Public Comment Process [40 CFR §50.14(c)(3)(v)(A-C)] .................................. 4 I.4 Mitigation of Exceptional Events [40 CFR §51.930] .......................................... 4 II Conceptual Model – A narrative that describes the event causing the exceedance and a discussion of how emissions from the event led to the exceedance at the affected monitor .................................................................................... 9 II.1 Description of the event causing the exceedance ............................................ 9 II.2 How emissions from the event led to an exceedance .................................... 10 III Clear Causal Relationship – A demonstration that the event affected air quality illustrating the relationship between the event and the monitored exceedance .................................................................................................................................. 18 III.1 Summary of Forecasts and Warnings ................................................................... 32 III.2 Summary of Wind Observations ............................................................................ 32 IV Concentration to Concentration Analysis – An analyses comparing the event- influenced concentrations to concentrations at the same monitoring site at other times .............................................................................................................................. 33 V Both Not Reasonably Controllable and Not Reasonably Preventable – A demonstration that the event was both not reasonably controllable and not reasonably preventable ........................................................................................................... 44 V.1 Wind Observations ...................................................................................................... 45 V.2 Review of Source Permitted Inspections and Public Complaints ............... 46 VI A Natural Event – A demonstration that the event was a human activity that is unlikely to recur at a particular location or was a natural event .............................. 49 VI.1 Affects Air Quality ........................................................................................................ 49 VI.2 Not Reasonably Controllable or Preventable .................................................... 49 VI.3 Natural Event ................................................................................................................. 50 VI.4 Clear Causal Relationship .......................................................................................... 50 i May 6, 2017 Exceptional Event, Imperial County Table of Contents VI.5 Concentration to Concentration Analysis ........................................................... 50 VI.6 Conclusion ...................................................................................................................... 51 Appendix A: National Weather Service Notices ......................................................................... 52 Appendix B: Wind Data ...................................................................................................................... 161 Appendix C: Public Information and other Notices ................................................................. 167 ii May 6, 2017 Exceptional Event, Imperial County Table of Contents LIST OF FIGURES FIGURE PAGE Figure 1-1 Imperial County ............................................................................................................. 6 Figure 1-2 Monitoring Sites in And Around Imperial County ............................................ 8 Figure 2-1 Monitoring and Meteorological Sites .................................................................. 11 Figure 2-2 Concentrations for All Sites Listed In Table 2-1 ................................................ 13 Figure 2-3 Local and Vicinity Airport Wind Speeds And Gust .......................................... 14 Figure 2-4 Wind Speeds and Gust Upstream Sites ............................................................... 15 Figure 2-5 HYSPLIT Model All Sites May 6, 2017 Ending 1200 PST ................................ 16 Figure 2-6 HYSPLIT Model All Sites May 6, 2017 Ending 1700 PST ................................ 17 Figure 3-1 MODIS Satellite Image May 6, 2017 ..................................................................... 19 Figure 3-2 Visual Ramp-up Analysis as Discussed for May 6, 2017 ................................ 20 Figure 3-3 72-Hour Time Series PM10 Concentrations and Visibility .............................. 21 Figure 3-4 Imperial Valley Air Quality Index for Brawley May 6, 2017 ........................... 29 Figure 3-5 Imperial Valley Air Quality Index for Calexico May 6, 2017 .......................... 30 Figure 3-6 Imperial Valley Air Quality Index for El Centro May 6, 2017 ........................ 30 Figure 3-7 Imperial Valley Air Quality Index for Niland May 6, 2017 ............................. 31 Figure 3-8 Imperial Valley Air Quality Index for Westmorland May 6, 2017 ............... 31 Figure 4-1 Brawley Historical Comparison FRM and FEM PM10 24-Hr Avg Concentrations January 1, 2010 to May 6, 2017 .............................................. 34 iii May 6, 2017 Exceptional Event, Imperial County Table of Contents Figure 4-2 Calexico Historical Comparison FRM and FEM PM10 24-Hr Avg Concentrations January 1, 2010 to May 6, 2017 .............................................. 35 Figure 4-3 El Centro Historical Comparison FRM and FEM PM10 24-Hr Avg Concentrations January 1, 2010 to May 6, 2017 .............................................. 36 Figure 4-4 Niland Historical Comparison FRM and FEM PM10 24-Hr Avg Concentrations January 1, 2010 to May 6, 2017 .............................................. 37 Figure 4-5 Westmorland Historical Comparison FRM and FEM PM10 24-Hr Avg Concentrations January 1, 2010 to May 6, 2017 .............................................. 38 Figure 4-6 Brawley Seasonal Comparison FRM and FEM PM10 24-Hr Avg Concentrations April 1, 2010 to May 6, 2017 .................................................... 39 Figure 4-7 Calexico Seasonal Comparison FRM and FEM PM10 24-Hr Avg Concentrations April 1, 2010 to May 6, 2017 .................................................... 40 Figure 4-8 El Centro Seasonal Comparison FRM and FEM PM10 24-Hr Avg Concentrations April 1, 2010 to May 6, 2017 .................................................... 41 Figure 4-9 Niland Seasonal Comparison FRM and FEM PM10 24-Hr Avg Concentrations April 1, 2010 to May 6, 2017 .................................................... 42 Figure 4-10 Westmorland Seasonal Comparison FRM and FEM PM10 24-Hr Avg Concentrations April 1, 2010 to May 6, 2017 .................................................... 43 Figure 5-1 Regulation VIII Graphic Timeline Development ................................................ 45 Figure 5-2 Permitted Sources ....................................................................................................... 47 Figure 5-3 Non-Permitted Sources ............................................................................................. 48 iv May 6, 2017 Exceptional Event, Imperial County Table of Contents LIST OF TABLES TABLE PAGE Table 1-1 Title 40 CFR §50.14(c)(3)(iv) Checklist .................................................................... 1 Table 1-2 Procedural Checklist .................................................................................................... 2 Table 2-1 Hourly Concentrations of Particulate Matter ..................................................... 12 Table 3-1 Wind Speeds and PM10 Concentrations for Brawley May 6, 2017 ............. 23 Table 3-2 Wind Speeds and PM10 Concentrations for Calexico May 6, 2017 ............ 24 Table 3-3 Wind Speeds and PM10 Concentrations for El Centro May 6, 2017 .......... 25 Table 3-4 Wind Speeds and PM10 Concentrations for Niland May 6, 2017 ............... 26 Table 3-5 Wind Speeds and PM10 Concentrations for Westmorland May 6, 2017 .................................................................................................................... 27 Table 3-6 Wind Speeds and PM10 Concentrations All Monitors May 6, 2017 ........... 28 v May 6, 2017 Exceptional Event, Imperial County Table of Contents ACRONYM DESCRIPTIONS AOD Aerosol Optical Depth AQI Air Quality Index AQS Air Quality System BACM Best Available Control Measures BAM 1020 Beta Attenuation Monitor Model 1020 BLM United States Bureau of Land Management BP United States Border Patrol CAA Clean Air Act CARB