Changestothebacteriathatliveinsideallofusareresponsibleforincreasingthenumberofpeoplewithallergies,suggestsnewresearch. InthisepisodeofHorizon,theshowinvestigatesthisclaimbyconductingauniqueexperimentwithtwoallergicfamiliesinordertofindoutjustwhatitisinthemodernworldthatistoblame.Witharaftofminicameras,GPSunitsan..bbb