During the Berlin Ozone Experiment BERLIOZ in July–August 1998 quasi-continuous measurements ofC₂–C₁₂ nonmethane hydrocarbons (NMHCs) were carried out at 10 sites in and around the city of Berlin using on-line gas-chromatographic systems (GCs) with a temporal resolution of 20–120 minutes. Additional airborne NMHCmeasurements were made using canister sampling on three aircraft and an on-line GC system on a fourth aircraft. The ground based data are analyzed to characterize the different sites and to identify the influence of emissions from Berlin on its surroundings. Benzene mixing ratios at the 4 rural sites were rather low (<0.5 ppbv).="" berlin="" (and="" the="" surrounding="" highway="" ring)="" was="" identified="" as="" the="" main="" source="" of="" anthropogenic="" nmhcs="" at="" eichstädt="" and="" blossin,="" whilst="" other="" sources="" were="" important="" at="" the="" furthermost="" site="" menz.="" the="" median="" toluene/benzene="" concentration="" ratio="" in="" berlin="" was="" 2.3="" ppbv/ppbv,="" agreeing="" well="" with="" measurements="" in="" other="" german="" cities.="" as="" expected,="" the="" ratios="" at="" the="" background="" sites="" decreased="" with="" increasing="" distance="" to="" berlin="" and="" were="" usually="" around="" one="" or="" below.="" on="" 20="" and="" 21="" july,="" the="" three="" northwesterly="" sites="" were="" situated="" downwind="" of="" berlin="" and="" thus="" were="" influenced="" by="" its="" emissions.="" considering="" the="" distance="" between="" the="" sites="" and="" the="" windspeed,="" the="" city="" plume="" was="" observed="" at="" reasonable="" time="" scales,="" showing="" decreasing="" toluene/benzene="" ratios="" of="" 2.3,="" 1.6="" and="" 1.3="" with="" increasing="" distance="" from="" berlin.="" isoprene="" was="" the="" only="" biogenic="" nmhc="" measured="" at="" berlioz.="" it="" was="" themost="" abundant="" compound="" at="" the="" background="" sites="" on="" the="" hotter="" days,="" dominating="" the="" local="" nmhc="" reactivity="" with="" averaged="" contributions="" to="" the="" total="" oh="" loss="" rate="" of="" 51%="" and="" 70%="" at="" pabstthum="" and="" blossin,="" respectively.="" emissionratios="" (relative="" to="" co="" and="" to="" the="" sum="" of="" analysed="" nmhcs)="" were="" derived="" from="" airborne="" measurements.="" the="" comparison="" with="" an="" emission="" inventory="" suggests="" traffic-related="" emissions="" to="" be="" the="" predominating="" source="" of="" the="" considered="" hydrocarbon="" species.="" problems="" were="" identified="" with="" the="" emission="" inventory="" for="" propane,="" ethene="" and="">