Raw Data Introduction¶
There three types of transactions is used to report sample values (raw data).
Type RD - Normal samples,
Type RB - Blank samples,
Type RC - Composite samples,
The transactions in this group are used to insert, update, and delete the individual observations of parameter values in the AQS database. Most of the parameter values are the concentrations of air pollutants measured with various methods and at various time intervals. Some non-pollutant observations are also reported, such as wind speed and other meteorological values. Together, these observations of parameter values are collectively called raw data because they are the actual values reported to AQS (even though in some cases they represent several atmospheric observations that are averaged to an hourly duration). There are three types of Raw Data, Normal, Blank, and Composite.
Normal Raw Data are the daily or shorter duation sample values that have been collected (or averaged) by monitoring stations that can be defined for a given date and time of day. These may be daily, sub-daily, hourly, or sub-hourly durations. The “observation time” is always the beginning of the period the data represents. The atmospheric observation period is the begin time plus the sample duration.
Blanks Raw Data are those collected from filters that have only gone through part of the process normally used for collecting data and represent artifacts in data related to things outside of atmospheric pollutant concentrations.
Composite data are concentration values derived from two or more air samples obtained at different times and combined and analyzed as one sample. Composite submissions have been deprecated from AQS. AQS will stop accepting composite data in the near future. The format is left in this document for interpreting composite data output from AQS.
Null reason codes are used to indicate why a scheduled sample was not collected. A transaction should be reported to AQS for every scheduled sample of a monitor. If the monitor did not collect data for any reason, leave the sample value null and include the best null reason code as the qualifier.
The qualifier field is used to flag a data with an indication that something was exceptional about its collection. There are three types of qualifiers: informational, request exclusion, and quality assurance.
Informational qualifiers are used to indicate to users of the data that the value was collected under unusual environmental circumstances. AQS treats this data as it would any other data and carries the qualifier along for the information of any users of the data.
Request Exclusion qualifiers are added to data where the submitter is requesting that the data be excluded from NAAQS consideration. The reasons for exclusion are the same as for informational qualifiers, but a different code is used to incidate to the system that this data will enter the exclusoin process. This data must be accompanied by a demonstration supporting the reason and the EPA regional office must approve the exclusion. Details of the process are in the Exceptional Event Rule at: https://www.epa.gov/air-quality-analysis/treatment-air-quality-data-influenced-exceptional-events-homepage-exceptional
Quality Assurance (QA) qualifiers are used to indicate to users of the data that the value was collected under unusual operational circumstances. AQS treats this data as it would any other data and carries the qualifier along for the information of any users of the data.
Insert actions are used to enter raw data values where none previously existed. The monitor reporting the raw data values must already exist in the database. Delete actions are used to remove one or more existing raw data values from the AQS database. Update actions are used to change existing raw data values.