TheincidenceoflungcancerintheGejiuareaofYunnanProvinceranksthefirstintheworld.Theradonlevel(indoor,soil)wasmeasuredintheGejiuareabytheSSNTDmethodfrom1990to1996,Theresultindicatesanextensivehigh-levelofindoorradoninthatareathoughUandTharelowerinlocallimestones,Theindoorradonlevelofhouseslocatedinthegeologicfaultzoneis6timeshighthat2kmfarfromthefaultzone.Thereasonprobablyisthattheradonlevelofsoilinthefaultis6-8timeshighthat1kmfarfromthefaults.ourdataindicatethatalowerrangeofradonlevels,0-100Bq.m^-3,existsinhealthyfamilies.However,ahigherradonlevel,over800Bq.m^-3,isoftenfoundcorrespondingtothatofcancerpatients'homes(thehouse-ownersaresufferingfromeitherlungcancerorleukaemiaorlivercancer),Obviously,anincreaseinlungcancerincidencefollowsanincreaseinindoorradonlevel,Theriskofcancerinducedbyindoorradonisnolongeraninference,butafact.
