Get Moving: Who's that camping by the motorway extension?

Q: What is that strange aerial-festooned caravan on the corner of Maioro St and Richardson Rd in Mt Roskill? Has it to do with the extension to State Highway 20 or something more sinister? Harry James, Avondale.

A: It has everything to do with the SH20 extension, and nothing more ominous than that. The quaint aluminium ladder on top of the caravan is an air quality monitor.

It was set up by the National Institute of Weather and Atmospheric Research at the request of Transit, after public consultation. It measures pollutants such as carbon monoxide and particulate matter.

This site was chosen because it is a very busy intersection and there is a slight uphill rise before the lights, which means that traffic, having just puffed up that little hill, will sit at the lights and blow out exhaust fumes towards Christ the King School across the road.

There are other schools along the motorway extension, such as the ones in Mt Roskill, but they are believed to have lower pollution risk because (hopefully) the traffic will be moving when it goes past, causing air movement, lessening the likelihood of pollution settling.

The caravan will be gone by December 9. Air quality will be measured again after the motorway extension is completed in 2009-2010 but, according to experiments, any increase in air pollution should fall within guidelines set by the Auckland Regional Council.

Brickbat: The answer this month to a reader's question about Hendry Ave in Hillsborough did not reveal the true situation. Residents are truly inconvenienced by the motorway extension work. Part of the avenue is now single lane, the grass area opposite the houses is being used as a work site, with attendant trucks, prefabs and noise, and drainage work in the street must be very disruptive. My response at the time was that traffic avoidance, or rat-running, would be the worst of their worries. I now feel it's probably the least.