Nitrogen dioxide

Traffic-related air pollution is measured across the region by a network of low cost nitrogen dioxide (NO2) passive diffusion tubes. (A picture of NO2 tube site can be seen here). Air pollution levels from traffic vary considerably across the region and so a larger monitoring network is needed to capture representative regional and local trends. Some sites are also part of NZTA’s national monitoring network. The passive tubes are a manual method and data is only available as monthly averages after the tube has been analysed in the lab.

Core sites

Benchmarking & Resources has more information on the guidelines and standards used for the following summary tabs.

Annual summary

The map shows annual average NO2 (μg/m3) from core monitoring sites across the region. The table also shows the annual summary for NO2 reported as a 24-hour average and as a 1-hour average from core monitoring sites across the region. The national standard allows nine 1-hour averages per year to be higher than 200 μg/m3 (10th highest value). The national guideline is a maximum 24-hour average of 200 μg/m3. The World Health Organization guideline is 40 μg/m3.

  • Drag and scroll on the map to move and zoom in on areas of interest.
  • Hover on the site circles to see more information.
  • Use the selection box ( ) to subset the map and table data to that area.
  • Click on sites in the table to highlight them on the map.
  • Use the arrows ( ↓↑ ) next to the table headers to sort the data.