The Council has a ‘surveillance’ work programme in place to better understand air quality in some of our smaller towns – Brightwater and Wakefield, Murchison and Takaka. Working with Mote Limited, a work programme has been developed to undertake temporary winter-time monitoring using a network of ‘dustmote’ sensors (Met One ES642 near-forward nephelometers) which are suitable for research purposes.
The National Environmental Standards for Air Quality only requires the identification and monitoring of airsheds where air quality standards are likely to be breached. Completion of this surveillance monitoring will inform the Council and community if there is a need for ongoing monitoring and to introduce management tools.
The NES-AQ has been under review for several years. There is a standard for PM10 (particulate matter), but there are currently no standards or guidelines in New Zealand for PM2.5. More recent international investigations suggest that greater focus should be placed on the management of smaller particles, PM2.5, as these are typically more harmful and are more controllable, given their greater apportionment to anthropogenic sources relative to PM10. For this reason, Council’s surveillance air quality monitoring programme is focusing on PM2.5, in anticipation of future legislative requirements to monitor and manage PM2.5. In the interim, Council is using the World Health Organisation’s PM2.5 guidelines as a comparison.
Short term research monitoring was previously undertaken in Wakefield and Brightwater during the 2006-2008 winters for PM10. The limited results suggested that air quality was generally good in Wakefield but there was possibly isolated ‘hot spots’ of poor air quality in Brightwater.
Over the winter 2022 monitoring period, a network of three dustmote sensors (PM2.5) were located in both Brightwater and Wakefield. An anemometer measured meteorological conditions. Council also co-located a Partisol gravimetric air quality sampler (R&P Model 2000) which is a reference monitoring instrument at one of the Brightwater locations, also monitoring PM2.5. This was the first time Council had completed short term research monitoring in the town for PM2.5.
The results of monitoring indicate:
|
Location |
Number of days where 24-hour average PM2.5 is greater than 15 µg/m3 |
Allowable number of exceedances per year |
Number of days where PM2.5 breaches 2021 WHO guideline |
|
Brightwater north |
27 |
3 |
24 |
|
Brightwater central |
7 |
3 |
4 |
|
Brightwater south |
0 |
3 |
0 |
|
Wakefield north |
45 |
3 |
42 |
|
Wakefield central |
27 |
3 |
24 |
|
Wakefield south |
2 |
3 |
0 |
Read the full report: Wakefield and Brightwater PM2.5 Study Winter 2022 (pdf 1.3 MB)
Following this temporary monitoring, in 2023 the Council commissioned emission inventories in Wakefield and Brightwater to better understand the sources of air pollution. Inventories are used to help inform management options if these may be required in the future.
Read the full reports:
Over the winter 2023 monitoring period, a network of three dustmote sensors (PM2.5) and an anemometer (measuring meteorological conditions) were located in Murchison. This was the first time Council had completed short term research monitoring in the town for PM2.5.
The results indicate that:
|
Location |
Number of days where 24-hour average PM2.5 is greater than 15 µg/m3 |
Allowable number of exceedances per year |
Number of days where PM2.5 breaches 2021 WHO guideline |
|
Murchison North |
0 |
3 |
0 |
|
Murchison Central |
5 |
3 |
2 |
|
Murchison South |
3 |
3 |
0 |
The Murchison study ran concurrently with temporary monitoring in Motueka. The Motueka monitoring included a dustmote co-located with a TDC monitoring instrument (Partisol) at Ledger Goodman Park, Motueka.
Read the full report: Murchison and Motueka PM2.5 monitoring network – May to September 2023 (pdf 989 KB)
Council is seeking budget in the 2024-2034 Long Term Plan to undertake surveillance monitoring in Takaka in winter 2027. This will be the first time Council has undertaken short term research monitoring in the town for PM2.5.
There are currently no standards in New Zealand for PM2.5. However, the surveillance monitoring will ensure that we are well informed to make decisions regarding PM2.5 monitoring and management options once the review of the NES-AQ is completed. The NES-AQ only requires the identification and monitoring of airsheds where air quality standards are likely to be breached.
Staff will continue to provide district wide education and best practice advice regarding home heating and outdoor burning as part of the Council’s wider air quality work programme.
For more information on this monitoring programme, please contact Anna MacKenzie (Resource Scientist - Contaminants) or Diana Worthy (Team Leader – Natural Resources Policy).
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