You gotta wonder how many watts his jammer was putting out if it was able to affect a cell phone tower than was several hundred feet away if not further. There are 100-watt mobile models available.
I'm not one of those people who think the minuscule power a cell phone puts out is going to rot your brain from occasional use but I've got to imagine that lots of watts in close proximity at that frequency can't be good. Especially daily for two years.
Oddly enough, using this RF calculator, seems to show no safety problems except, possibly, for the cars directly adjacent.