The National Environmental Standard (NES) for Air Quality
The NES for PM10 allows the threshold of 50 µg m-3 to be exceeded on no more than one day per 12 month period. If this is exceeded the NES has been breached and Council is required to notify exceedances.
Blenheim typically exceeds the NES for PM10 3-5 times a year, but in 2017 it exceeded the NES 10 times, while in 2019 there were no exceedances. The highest concentration recorded was 85 µg m-3 in 2004, but typically the highest concentrations are between 51-67 µg m-3.
|Date of Exceedance||Location of Exceedance||PM10 (µg m³)|
|18 June 2021||Redwoodtown||54.4|
|16 June 2021||Redwoodtown||61.0|
|11 June 2021||Redwoodtown||57|
|7 June 2021||Redwoodtown||51|
|5 June 2021||Redwoodtown||55.9|
|4 June 2021||Redwoodtown||77.5|
|3 June 2021||Redwoodtown||62.9|
|2 July 2020||Redwoodtown||66.4|
|30 May 2020||Redwoodtown||60.1|
|20 May 2020||Redwoodtown||51.5|
|1 August 2019||Redwoodtown||57|
The Marlborough District Council monitors PM10 concentrations relative to the NES at an air monitoring site in Redwoodtown.
The NES for PM10 allows the threshold of 50 µg m-3 to be exceeded on no more than 1 day per 12 month period. The last exceedance in 2020 for Blenheim occurred on 2 July 2020. These exceedances mean the NES has been breached on seven occasions in the Blenheim in 2021.