The state highway system accounts for about 12% of New Zealand’s roads and around half of the 40 billion vehicle kilometres New Zealanders travel each year. Motor vehicles travelling on roads emit an array of air pollutants which can contribute to harmful effects on human health and smog formation.
Waka Kotahi NZ Transport Agency is committed to being socially and environmentally responsible and has specific objectives in its state highway environmental plan for improving air quality, including:
Understand the contribution of vehicle traffic to air quality.
Ensure new state highway projects do not directly cause national environmental standards for ambient air quality to be exceeded.
Contribute to reducing emissions where the state highway network is a significant source of exceedances of national ambient air quality standards.
In 2007, Waka Kotahi began a national monitoring programme to determine relative levels of vehicle pollution across the state highway network. Passive samplers are now located at more than 120 sites across New Zealand to measure nitrogen dioxide (NO2) as a proxy for vehicle-related air pollution. The overall aim is to see a decreasing trend in NO2 concentrations measured at these sites. This aligns with the government’s desired long-term impact which seeks a ‘reduction in adverse environmental (air quality) effects from land transport’ as stated in the Government Policy Statement on land transport.(external link)
The annual report summarises the data measured at the national network sites since 2007. It is complemented by a metadata report, which provides details for each site in the network, and an operating manual which outlines how the network is operated.
|2007–2012 annual report [PDF, 9.1 MB]||Oct 2013|
|2007–2013 annual report [PDF, 7 MB]||Mar 2015|
|2007–2014 annual report*|
|2007–2015 annual report*||Oct 2016|
|2007–2016 annual report*||Nov 2017|
|2007–2019 annual report [PDF, 2.1 MB]||Aug 2020|
|2007–2020 annual report [PDF, 1.3 MB]||Aug 2021|
|2007–2021 annual report [PDF, 1.3 MB]||Dec 2022|
*These annual reports are available on request from email@example.com. It should be noted that data contained within these reports, for the 2013 year, has been found to include errors (affecting 2013 annual and seasonal averages).
|2007–2010 site metadata [PDF, 13 MB]||May 2011|
|2007–2012 site metadata [PDF, 5.4 MB]||Apr 2013|
|2007–2020 site metadata [XLSX, 1.4 MB]||Aug 2021|
|2007–2021 site metadata [XLSX, 1.4 MB]||Dec 2022|
|2012–2013 operating manual, first edition [PDF, 1.7 MB]||Sep 2012|
|2013–2014 operating manual, first edition [PDF, 2.9 MB]||Sep 2013|
|2017–2018 operating manual, third edition [PDF, 9 MB]||Oct 2017|
|Air quality monitoring in The Terrace and Mt Victoria Tunnels, Wellington [PDF, 3.7 MB]||Jun 2009|
|Trends in transport related air pollution in NZ (CASANZ Transport Special Interest Group presentation) [PDF, 1.2 MB]||Sep 2013|