Air Quality Statistics

Formerly the air quality indicators representing the provisional and final figures. The indicators measure annual UK levels of pollution from particulates (PM10) and ozone (O3), the two pollutants thought to have the greatest health impacts, as well as the number of days on which levels of any one of five pollutants were ‘moderate or higher’.

Designation: National Statistics Alternative title: Air Quality Indicators

Notes: Since 2008, upgrade of numerous PM10 monitoring instruments has enabled correction of measurements taken from sites using older equipment, by using the Volatile Correction Model (VCM). These results are shown in parentheses. Non-VCM corrected data for 2008 and 2009 are retained here for the purpose of year-on-year comparison. VCM corrections for 2010 are currently not available.

Not every site in the automatic monitoring network is included. Sites must also meet certain data capture targets to be used in the index. Urban sites are required to monitor PM10 and rural sites are required to monitor ozone.For the required pollutants, 1987-97 data capture should be more than or equal to 50% of the year, and from 1998 onwards it should be more than or equal to 75% of the year. For ozone this applies to both the full year and the summer period (= 1st Apr – 30th Sep) in isolation.