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Trends in Auckland’s air quality 2006-2018

Nick Talbot, Paul Crimmins
Auckland Council Research and Evaluation Unit, RIMU
Publication date:  

From the Executive summary:

Pollutants in the air cause adverse health effects and reduced visibility. Air pollution in the Auckland
region has been monitored by Auckland Council since the late 1990s at representative monitoring
sites using high-accuracy equipment in accordance with applicable Australian and New Zealand
standards. The purpose of the regional air quality monitoring programme is to ensure that there is
good scientific understanding of pollutant levels, trends and sources, in order for Auckland Council
to manage air quality. In addition, regional councils have a responsibility to monitor and manage
outdoor air quality under the Resource Management Act 1991.

Trends in air pollution across the Auckland air quality network between 2006 and 2018 (inclusive)
are reported here. Statistical analysis has been split into two separate time considerations, longterm
(2006-2018) and short-term (2013-2018). Seasonal and deseasonalised statistics are provided
for both time periods and for all measured variables across the Auckland network. Source
apportionment data for fine particulate matter (PM10 and PM2.5) has been included in the analysis
where available to identify emission sources.

In most locations, PM10 and PM2.5 had statistically significant decreasing monotonic trends for both
short- and long-term timeframes. Queen Street is not following this trend. This city centre site has
shown significant increases in PM2.5 and PM10 for the short-term analysis (P<0.001 and P<0.1,
respectively). Nitrogen dioxide (NO2) shows marked decreases in concentration over the long-term; however, short-term trends are starting to show increases in concentration at several sites near major roads. Queen Street has shown a statistically significant increase in NO2 since 2013 (P<0.001) and has for the past two years exceeded Auckland’s ambient air quality target for NO2 of 40 μg/m3 per annum.

This report provides an analysis of air quality across Auckland, changes over time, key factors
driving the observed patterns and how policy and regulatory responses impact the quality of
Auckland’s air. The need for more city centre monitoring is apparent to further investigate recently
increasing trends.

Auckland Council technical report, TR2020/004

February 2020

See also

Reduction of air pollution levels seen in the Auckland Council air quality monitoring network two weeks after the Covid19 lockdown (Level 4 Alert)