When you use your cellphone, it connects to the main telephone network through a cellsite. Cellsites are also known as cellphone towers or base stations.
Cellsites communicate with nearby cellphones using radio signals. These radio signals are made up of radiofrequency fields.
So that people aren’t exposed to strong radiofrequency fields, cellsites must operate within the limits set out under the New Zealand radiofrequency field exposure standard.
Radiofrequency field levels near cellsites
People living near cellsites are only exposed to weak radiofrequency fields. This is because cellsites:
- are designed to send most of the radio signals away from the site, not to the area right next to it
- automatically adjust their power, so they use just enough to handle calls going through the site
- can’t transmit above a maximum power level.
Measurements of radiofrequency fields around towers
Measurements have been taken around several hundred cellsites in New Zealand.
- At most sites, the highest exposure is less than 1% of the limit in the New Zealand exposure standard.
- Where exposures are higher, they are rarely more than a few percent of the limit. None has exceeded the limit.
- Exposures are even lower if there is no direct line of sight to the cellsite.
Overall, the research evidence does not show that such low exposures can harm your health.
Exposure levels around multiple cellsites
Maximum exposures generally aren’t any stronger even where cellsites are close together. Each cellsite only has a small area where the exposure is highest. Radiofrequency fields quickly get weaker outside that area. It would be unusual for 2 or more sites to have those areas fall close together.
Cellphone technology has evolved over the years as the numbers of users and demand for data has increased. 5G, the next iteration of cellphone technology, will start to be used in 2020 – although a few test sites might operate before then.
The way information is encoded onto the 5G radio signal is similar to 4G.
- Cellsites using 5G will have to comply with the New Zealand exposure standard.
- Initially 5G will use frequencies similar to those already used by cellsites. Eventually higher frequencies will be used. The existing New Zealand exposure standard covers all these frequencies, and research published since the standard was adopted still supports the limits set in the standard.
- Measurements at test sites suggest that exposures from 5G transmitters will be similar to those from the current technologies.
- As happens already, if demand increases then more sites will be needed, each covering a smaller area. As they cover a smaller area, they will need less power, so exposures should be no greater than around existing sites.
Finding out about local cellsites
If you want to find out about exposures from a specific cellsite, you could ask:
- the company which operates the site
- the planning department of your local council – they may have received exposure estimates before a site was installed, or requested measurements once it was operating.
Find out more from the Ministry
You can download independent monitoring reports commissioned by companies that operate cellsites at Cellsite monitoring.
An interagency committee monitors research into the health effects of radiofrequency fields. Find out more at Research into non-ionising radiation.
NZS 2772.1:1999 Radiofrequency fields – Maximum exposure levels sets out limits for exposure to the radiofrequency radiation. Find out more at Radiofrequency field exposure standard.