Council is required to undertake air quality monitoring under the National Environmental Standards for Air Quality (NESAQ). This provides valuable information on the state of Nelson’s air quality and effectiveness of Council’s management of its responsibilities as a unitary authority under the Resource Management Act.
We compare concentrations measured in Nelson to the National Environmental Standards for Air Quality (NESAQ). These are legally binding levels of air pollution that must not be exceeded. The NESAQ requirements for particulates are being revised, and this is likely to result in a new, stricter standard for PM2.5. It is also useful to compare Nelson’s concentrations to the World Health Organisation (WHO, 2021) guidelines. These are international guidelines rather than requirements we must meet.
Monitoring of PM10, PM2.5 and Gases
We have been regularly monitoring concentrations of PM10 for more than 20 years, and since 2018 we have been measuring PM2.5. Monitoring data is collected from four ‘airsheds’ shown in Figure 1. We also monitor concentrations of gases such as nitrogen dioxide, but on a less frequent basis with the last survey of nitrogen dioxide in 2021.
The good news is our PM10 concentrations comply with the NESAQ for PM10 and we no longer have ‘polluted’ airsheds. Since 2002 we have implemented our Nelson Air Quality Plan, which required a range of measures to be undertaken related to domestic heating and outdoor burning to improve air quality, as well as improvements in PM10 emissions from industrial activities. However, in some areas our PM2.5 concentrations are above the WHO (2021) guidelines, specifically in the Tāhunanui and Nelson South airsheds.
