<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE EPA_Null_Data_Codes>

<EPA_Null_Data_Codes>
   <Null_Code id="AA" airs_code="9967" description="Sample Pressure out of Limits" />
   <Null_Code id="AB" airs_code="9968" description="Technician Unavaliable" />
   <Null_Code id="AC" airs_code="9969" description="Construction/Repairs in Area" />
   <Null_Code id="AD" airs_code="9970" description="Shelter Storm Damage" />
   <Null_Code id="AE" airs_code="9971" description="Shelter Temperature Outside Limits" />
   <Null_Code id="AF" airs_code="9972" description="Scheduled but not Collected" />
   <Null_Code id="AG" airs_code="9973" description="Sample Time out of Limits" />
   <Null_Code id="AH" airs_code="9974" description="Sample Flow Rate out of Limits" />
   <Null_Code id="AI" airs_code="9975" description="Insufficient Data (cannot calculate)" />
   <Null_Code id="AJ" airs_code="9976" description="Filter Damage" />
   <Null_Code id="AK" airs_code="9977" description="Filter Leak" />
   <Null_Code id="AL" airs_code="9978" description="Voided by Operator" />
   <Null_Code id="AM" airs_code="9979" description="Miscellaneous Void" />
   <Null_Code id="AN" airs_code="9980" description="Machine Malfunction" />
   <Null_Code id="AO" airs_code="9981" description="Bad Weather" />
   <Null_Code id="AP" airs_code="9982" description="Vandalism" />
   <Null_Code id="AQ" airs_code="9983" description="Collection Error" />
   <Null_Code id="AR" airs_code="9984" description="Lab Error" />
   <Null_Code id="AS" airs_code="9985" description="Poor Quality Assurance Results" />
   <Null_Code id="AT" airs_code="9986" description="Calibration" />
   <Null_Code id="AU" airs_code="9987" description="Monitoring Waived" />
   <Null_Code id="AV" airs_code="9988" description="Power Failure" />
   <Null_Code id="AW" airs_code="9989" description="Wildlife Damage" />
   <Null_Code id="AX" airs_code="9990" description="Precision Check" />
   <Null_Code id="AY" airs_code="9991" description="Q C Control Points (zero/span)" />
   <Null_Code id="AZ" airs_code="9992" description="Q C Audit" />
   <Null_Code id="BA" airs_code="9993" description="Maintenance/Routine Repairs" />
   <Null_Code id="BB" airs_code="9994" description="Unable to Reach Site" />
   <Null_Code id="BC" airs_code="9995" description="Multi-point Calibration" />
   <Null_Code id="BD" airs_code="9996" description="Auto Calibration" />
   <Null_Code id="BE" airs_code="9997" description="Building/Site Repair" />
   <Null_Code id="BF" airs_code="9998" description="Precision/Zero/Span" />
   <Null_Code id="BG" airs_code="9966" description="Missing ozone data not likely to exceed level of standard" />
   <Null_Code id="BH" airs_code="9965" description="Interference/co-elution/misidentification" />
   <Null_Code id="BI" airs_code="9964" description="Lost or damaged in transit" />
   <Null_Code id="BJ" airs_code="9963" description="Operator Error" />
   <Null_Code id="BK" airs_code="9962" description="Site computer/data logger down" />
   <Null_Code id="BL" airs_code="9961" description="QA Audit" />
   <Null_Code id="BM" airs_code="9960" description="Accuracy check" />
   <Null_Code id="BN" airs_code="9947" description="Sample Value Exceeds Media Limit" />
   <Null_Code id="CS" airs_code="9953" description="Laboratory Calibration Standard" />
   <Null_Code id="DA" airs_code="9951" description="Aberrant Data (Corrupt Files, Aberrant Chromatography, Spikes, Shifts)" />
   <Null_Code id="DL" airs_code="9949" description="Detection Limit Analyses" />
   <Null_Code id="FI" airs_code="9959" description="Filter Inspection Flag" />
   <Null_Code id="MB" airs_code="9955" description="Method Blank (Analytical)" />
   <Null_Code id="MC" airs_code="9958" description="Module End Cap Missing" />
   <Null_Code id="SA" airs_code="9957" description="Storm Approaching" />
   <Null_Code id="SC" airs_code="9948" description="Sampler Contamination" />
   <Null_Code id="ST" airs_code="9954" description="Calibration Verification Standard" />
   <Null_Code id="TC" airs_code="9952" description="Component Check &amp; Retention Time Standard" />
   <Null_Code id="TS" airs_code="9956" description="Holding Time Or Transport Temperature Is Out Of Specs." />
   <Null_Code id="XX" airs_code="9950" description="Experimental Data" />
</EPA_Null_Data_Codes>
