Monitoring and Research

Visibility photos

Air pollution can affect the clarity and colour of air.

During the winter months, from May to October, we often see a brown haze over Auckland caused by air pollution. This haze usually disappears by about 1 pm, but occasionally lasts all day. Sometimes it is even possible to see a fog layer separate from the brown haze. Over the last eight years, the number of days when we have seen brown haze has ranged between three days in 2007 and forty seven days in 2001*. The frequency of these brown hazes depends a lot on the weather, for example the wind speed and direction and the temperature of the air.

* Note that analysis of the ARC photos was undertaken by Sonja Bhatja, supervised by Jennifer Salmond of the University of Auckland under a project funded by School of Geography, Geology & Environmental Sciences.

This is what Auckland's skyline looks like on a good, clear day.