Intercontinental transport of air pollution will e

Intercontinental transport of air pollution will emerging science lead to a New Hemispheric TreatyIntercontinentalTransportofAirPollution:WillEmergingScienceLeadtoaNewHemisphericTreaty?TRACEYHOLLOWAY*EarthInstitute,ColumbiaUniversity,2910Broadway,NewYork,NewYork10027ARLENEFIOREDepartmentofEarthandPlanetarySciences,HarvardUniversity,20OxfordStreet,Cambridge,Massachusetts02138MEREDITHGALANTERHASTINGSDepartmentofGeosciences,PrincetonUniversity,B-78GuyotHall,Princeton,NewJersey08544WeexaminetheemergenceofInterContinentalTransport(ICT)ofairpollutionontheagendasoftheairqualityandclimatecommunitiesandconsiderthepotentialforanewtreatyonhemisphericairpollution.ICTistheflowofairpollutantsfromasourcecontinent(e.g.,NorthAmerica)toareceptorcontinent(e.g.,Europe).ICTofairpollutantsoccursthroughtwomechanisms:(i)episodicadvectionand(ii)increasingtheglobalbackground,whichenhancessurfaceconcentrations.WeoutlinethecurrentscientificevidenceforICTofaerosolsandozone,bothofwhichcontributetoairpollutionandrad