Auckland air quality report October 2022

Author:

Louis Boamponsem, Auckland Council Research and Evaluation Unit, RIMU

Source:

Auckland Council Research and Evaluation Unit, RIMU

Publication date:

2022

Topics:

Environment

Extract:

Introduction

Auckland Council continuously collects air quality data to assess compliance with national standards and provide information to aid policy development and evaluation. The data the council collects enables us to quantify ambient air quality in the region and note spatial and temporal variations. This report presents a monthly update on air quality in Auckland. It has four sections: sections A and B present tables and graphics illustrating air quality status in the Auckland region based on the data collected from continuous monitoring sites across the region. For this edition, section C focuses on one monitoring site ̶ Henderson. Section D provides the monthly averages for 2022 and the past two to five years pollutant concentrations (when data is available). The monthly update is prepared using validated data which is generally available one month after raw data is collected. This update covers data to August 2022.

Summary

In August, there were three exceedances of the National Environmental Standard for Air Quality (NESAQ).
On 18-19 August, the Queen Street site recorded two exceedances of NESAQ for particulate matter (PM₁₀) (24-hour average). Our preliminary investigation indicated that these exceedances were most likely due to marine aerosol (sea salt) following a high sea state and onshore easterly wind conditions.
On 24/08/2022, the Khyber Pass Road site recorded one exceedance of NESAQ for nitrogen dioxide (NO₂) (1-hour average). The cause of this NO₂ NESAQ exceedance is under investigation but believed to be a stationary running motor vehicle.
Apart from the city centre sites, all the air quality monitoring sites recorded average NO₂ concentrations higher than the same period of the previous year (January to August).
As expected, the highest NO₂ concentrations were measured at the city centre sites, although the concentrations are lower than the same period of the previous year. Auckland transport traffic volume data collected between 15-21 August 2022, shows that 24 hour traffic volume at the city centre screenline intersections are between 70% to 80% relative to normal (pre-covid levels).
Most monitoring sites recorded particulate matter (PM₁₀) concentrations higher than the same period of the previous year (January to August).
Compared to the same period of the previous year, there has been a 38% decrease in carbon monoxide (CO) average concentration measured at the Khyber Pass Road monitoring site. This is most likely due to the 4% reduction in traffic volume at the carriageways to the monitoring site.
Air quality of a monitoring site can vary from year to year due to weather and other influences and for trend analysis of change see Table 2 and this report: Auckland Air quality report October 2021