About a year ago I wrote about claims of health risks associated with wireless technology. These claims have come to my home town in the form of opposition to the deployment of wireless water meters.
To find out if there was anything to the opposition, I contacted Dr. Maria Powell, a vocal opponent of my city’s plan to deploy wireless metering. She sent me some papers on the possible hazards of RF energy.
The papers suffered from the same main fallacy as I encountered researching my article last year: anomaly hunting. They start with the claim that there are unknown biological effects to athermal levels of RF energy and then look for any and all cases where something unexplained happened. The claim of some unknown biological effects is so broad, many anomalies can be brought out to support it.
One of the papers suggested a clear limit for RF field strength exposures: 0.614V/m. That works out to the field at 3m distance of an antenna radiation around 100mW. 100mW slightly more than the output a typical wireless router and slightly less than a mobile phone. Mobile phones would violate this rule by a huge margin because they’re used a distances << 3m from the body. The output of the water meters is probably in the 100mW range, and they only transmit once per hour.
I told Dr. Powell the meters would possibly meet the requirements she’s calling for. She responded with the following rebuttals:
- The 0.614V/m is a limit of field strength across the spectrum from all RF transmitters, not a rule for each device.
- The device could transmit at a higher duty cycle in a future usage scenario or in a failure mode.
- In a multipath environment there could be locations that get higher field strength that the free space loss equation would predict.
Would they accept the meters if it were proven that the the field strength in accessible areas near them was solidly under the limit they’re calling for? The answer was “No, I wouldn’t support the smart metering system even if I had no concerns about RF risks.” She brought up other concerns such as privacy and cost.
This made me suspect technology’s critics don’t like the meters for some other reason. The begin with the conclusion that there are problems with them and search for any data that might support that conclusion. Maybe something in their background makes them oppose technology in general. That made me think about my own background with radio. I got my first shortwave when I turned 11 and started experimenting with transmitters shortly after that. I have spent much of the past year with a 10mW 915MHz transmitter tapped to my shirt for antenna testing. I have my own reasons to be biased on this issue.
I suspect what the wireless critics in Madison area really trying to say goes something like this.
Some of new technologies turn out to be dangerous, and we cannot know for sure which one will be dangerous until we deploy them on a widespread basis. We shouldn’t deploy any technology unless the need it fills justifies the risk. Profit motive encourages us to deploy new technologies that we don’t really need.
Their science is wrong, but their motivations seem honest. I try to step beyond my own love for technology occasionally and remember the purpose of technology is solve problems and make the world a better place.
Note: Shortly after I published this, an old friend who installs water meters for his job called me. He recongized the model in the picture and said he installs meters like this all the time. He said while they do raise privacy concerns, they can spot leaks if they see the rate of flow never falls below a certain level. He also said he though this type of meter transmitted every 15 minutes, not every 60 minutes as the City of Madison claims. He seemed to think of it as a mundane part and was suprised the one time he met a customer who wanted to opt out.
Further Reading of RF Critics’ Views
Sage, Cindy and Carpenter, David O, “Public Health Implications of Wireless Technologies”, Pathophysiology 16 (2009) 233-246 - Contains a lot of logical fallacies but is worthwhile for introducing the 0.614V/m limit.
Hirsch, Daniel, “Health Impacts of Radio Frequency from Smart Meters” - Bizarrely argues Smart Meters expose people to more RF energy than mobile phones.
McNabb, John, “Vulnerabilities of Wireless Water Meter Networks” - This contains the privacy and security arguments they would use if safety were not an issue.