WiFi has been considered and promoted as being "a safe form of radiation" when under limits, however combine the overall exposure from multiple neighboring WiFi hotspots and you might have an over-limit exposure. There are numerous cases of "radiation sensitive" users complaining about health symptoms associated with WiFi usage which go away as soon as they get away from it. Common problems reported are feeling tired, Unable to concentrate, Negative thinking, depressive thoughts, less sleep etc.
Do watch the Canadian Documentary - "WiFi in schools proven dangerous" posted below (after clicking the Read more button below) which reports and investigates how WiFi exposure is causing heart problems, headaches and other neurological disorders in children.
![Wifi Hazards](http://www.megaleecher.net/sites/default/files/images/wifi-health-hazard.png)