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Border Air Quality Data - About the HAP Site Detail Report

What does the report tell me?

The border air quality data HAP Site Detail report lists ambient air monitoring results for all hazardous air pollutants (HAPs) monitored at one site in a year. It is an auxiliary report for the HAP Monitor Values report and the HAP Monitor Count report. Its principal purpose is to show which HAPs were reported by a particular site.

Each row of the HAP Site Detail report displays the name of a hazardous air pollutant and monitoring annual summary values for that pollutant. The report heading describes the monitoring site and identifies the data year.

Hazardous air pollutants are substances known or suspected to cause serious health problems.

How can I customize the report?

Sort Order

You can use the SORT buttons in each report column to change the order of rows in the report. The default sort order is ascending (alphabetical) pollutant name.

Detail or Summary

This is always a detail report, and there are no optional report columns. A row of the report always displays data for a single pollutant reported by a single monitoring site.

What do the report columns mean?

Row #
Sequence number of report rows (lines). Sequence numbers are not associated with particular rows; they simply enumerate the rows of a report from first to last. Thus, choosing an alternate sort order for a report would change the sequence numbers associated with particular rows.

Monitor ID
The AQS database identification code for a monitor. An AQS monitor ID has the following parts:
  • FIPS state code (2 digits)
  • FIPS county code (3 digits)
    FIPS is the acronym for Federal Information Processing Standards, which defines codes used in most U.S. government information systems.
  • AQS site code (4 digits) - an arbitrary code that identifies a particular monitoring site within a county
  • AQS parameter code (5 digits) - identifies the hazardous air pollutant measured
  • AQS monitor number (1 or 2 digits) - a sequence number that distinguishes among monitors for the same pollutant at the same site, also known as parameter occurrence code (POC).
For example, AQS monitor ID 06-073-0006-45202-1 is a toluene monitor in San Diego, CA (06 = California, 073 = San Diego County, 0006 = a monitoring site in the city, 45202 = toluene, 1 = an air sampler at the site).

The name of the hazardous air pollutant for the row of data.

Pollutant Values
# Obs
Number of days in the year for which values (observations) were reported.
1st Max, 2nd Max, 3rd Max, 4th Max
The four highest values for the year. Each value is a 24-hour average.
Arithmetic average of all 24-hour values for the year.

If a monitoring site reports a pollutant concentration that is less than the minimum detectable level for the measurement procedure used, a value equal to one-half the minimum detectable level is substituted for the reported concentration in the AQS database. Pollutant values given in this report - maximum and mean values - reflect the half-minimum-detectable substitutions.

The units of measurement for pollutant concentration:
  • ppbC = parts per billion carbon
    To convert from ppbC to parts per billion by volume (ppb), divide pollutant concentration by the number of carbon atoms in the pollutant molecule. In other words, ppbC = ppb * (number of carbon atoms).
  • µg/m3 = micrograms per cubic meter
  • ng/m3 = nanograms per cubic meter
Concentrations in micrograms or nanograms per cubic meter have been adjusted to standard pressure (760 millimeters of mercury, or 101.3 kPa) and temperature (25 degrees Centigrade, or 298 kelvins), except for measurements derived from fine particulate matter samples - those which include "(PM2.5)" in pollutant name. Fine particulate samples are not adjusted; they are reported using the "local conditions" of pressure and temperature at the time and place of measurement.

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