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Data and statistics

The Northern Ireland Air Quality Data Archive contains options for you to retrieve data (measurements and simple statistics) relating to Air Quality in Northern Ireland from 1986 to the present day.

The database contains tables of measured concentrations from the air quality monitoring sites operated by the Department of Agriculture Environment and Rural Affairs (DAERA) and Northern Ireland local authorities. The pre-calculated statistics in the database are calculated from these measurements. Emissions estimates - the amount of each air pollutant produced by a range of activities - can be obtained from the National Atmospheric Emissions Inventory (NAEI).

Emissions and concentration statistics shown in this database are National Statistics. National Statistics are produced to high professional standards set out in the National Statistics Code of Practice. They undergo regular quality assurance reviews to ensure that they meet customer needs. They are produced free from political interference. Further National Statistics are available from Defra's Statistics page.

Monitoring data

Automatic monitoring networks measure air pollutants in near real-time to produce hourly average concentrations. The measurements are collected from individual sites by dial-up modem. By clicking on the map on the Home Page of this web site you can get detailed information for each site presently in operation. At some sites the measurements go back to 1986.

Simple statistics

A range of simple statistics are routinely calculated by the database for the automatic monitoring data each night. These include:

  • Daily mean, maximum and minimum values for all pollutants.
  • 8-hour running mean values for ozone and carbon monoxide.
  • Daily maximum 8-hour running means for ozone.
  • Running 24-hour means for PM10 particulate matter.

Data output

There are three options for the output of your database download, according to the size of the data request. Small enquiries can be shown on your screen using minimum HTML, moderately sized enquiries can be e-mailed to you as an attachment in comma separated format (CSV).

The comma-separated format should make it easy to load the file into a spreadsheet once saved to your local machine. If the program does not recognise the format automatically, set the file type to "Text" and the separator as "Comma" when importing the file into Excel. A further option would be to rename the file to [NAME].csv where [NAME] is a filename of your choosing.

Data Verification and Ratification process

A description of the data verification and ratification process is available on the Data verification and ratification process page.