THE SOUTHEAST UNITED STATES IS HOME TO 65 MILLION PEOPLE LIVING IN CLOSE PROXIMITY TO THE GREATEST CONCENTRATION OF BIOMASS BURNING IN THE CONTIGUOUS UNITED STATES. SMOKE AND TRACE GASES EMITTED FROM THESE OPEN FIRES ARE IMPORTANT SOURCES OF PARTICULATE MATTER (PM2.5) AND OZONE AIR POLLUTION WHICH CAUSE CARDIOVASCULAR AND RESPIRATORY DISEASE AND ARE ALSO SIGNIFICANT CLIMATE-FORCING AGENTS. ACCURATELY CHARACTERIZING THE EMISSIONS AND RESULTING CONCENTRATIONS OF AIR POLLUTANTS IS CRITICAL FOR ASSESSING THE HEALTH AND CLIMATE CONSEQUENCES OF BIOMASS BURNING. OUR PRELIMINARY WORK HAS FOUND THAT THE CURRENT SATELLITE-BASED INVENTORIES OF FIRE AREA AND EMISSIONS UNDERESTIMATE FIRE EMISSIONS IN THE SOUTHEAST BY AS MUCH AS A FACTOR OF 4. THIS IMPLIES THAT THE HEALTH AND CLIMATE IMPACTS OF FIRES IN THE SOUTHEAST ARE MUCH LARGER AND MORE SEVERE THAN CURRENTLY THOUGHT. THE PROPOSED PROJECT WILL PRODUCE AN IMPROVED INVENTORY OF BIOMASS BURNING EMISSIONS IN THE SOUTHEAST AND THEN USE THE IMPROVED INVENTORY IN A 3-D CHEMICAL TRANSPORT MODEL (CTM) TO BETTER UNDERSTAND THE IMPACTS OF FIRE ON HUMAN HEALTH CLIMATE AND THE ENVIRONMENT. THE IMPROVED INVENTORY WILL BE DEVELOPED WITH HIGH-QUALITY GROUND-BASED FIRE SURVEYS (E.G. TALL TIMBERS RESEARCH STATION US MILITARY BASES US FOREST SERVICE) AND GOVERNMENT BURN AUTHORIZATIONS (E.G. FLORIDA FOREST SERVICE GEORGIA FORESTRY COMMISSION) PROVIDING GROUND-TRUTH TO CHARACTERIZE THE BIASES OF NASA S SATELLITE-BASED FIRE PRODUCTS IN THE SOUTHEAST US. OUR PRELIMINARY WORK IN FLORIDA HAS FOUND THAT DETECTION BIASES FOR MODERATE-RESOLUTION SATELLITE FIRE SENSORS ARE LARGER IN FORESTED AREAS WHERE UNBURNED CANOPY CAN OBSCURE FIRE BENEATH THAN IN AGRICULTURAL FIELDS. A STATISTICAL MODEL WILL BE DEVELOPED TO FULLY CHARACTERIZE THESE BIASES ACROSS THE SOUTHEAST BASED ON LAND COVER LAND USE FOLIAGE DENSITY FIRE SIZE AND SEASON. STATISTICAL UPSCALING WILL THEN BE USED TO RECONCILE THE SATELLITE-BASED EMISSIONS WITH GROUND-BASED FIRE DATA. THE IMPROVED BIOMASS BURNING EMISSION INVENTORY WILL BE IMPLEMENTED WITHIN THE GEOS-CHEM 3-D GLOBAL CTM WHICH HAS HIGH SPATIAL RESOLUTION OVER THE UNITED STATES. GEOS-CHEM SIMULATIONS WITH ORIGINAL AND IMPROVED BIOMASS BURNING EMISSIONS WILL BOTH BE EVALUATED AGAINST AEROSOL AND AIR QUALITY MEASUREMENTS IN THE SOUTHEAST FROM GROUND-BASED NETWORKS (AQS SEARCH IMPROVE CASTNET CSN AERONET) AND NASA REMOTE SENSING (AERONET MODIS MISR MOPITT OMI) TO FURTHER TEST THE IMPROVED EMISSION INVENTORY. FINALLY THE IMPROVED GEOS-CHEM MODEL WILL BE USED TO DIAGNOSE THE CONSEQUENCES OF INCREASED BIOMASS BURNING FOR AIR QUALITY HEALTH AND CLIMATE IN THE SOUTHEAST US. OUR PRELIMINARY MODEL TESTS HAVE ALREADY FOUND THAT THE INCREASED EMISSIONS HAVE A SIGNIFICANT IMPACT ON BOTH MEAN AND EXTREME PM2.5 CONCENTRATIONS AT LEVELS THAT ARE KNOWN TO HARM PUBLIC HEALTH. THE SPECIFIC DIAGNOSTICS IN THE PROPOSED WORK WILL INCLUDE THE NUMBER OF DAYS WITH PM2.5 OR O3 EXCEEDING THE NATIONAL AMBIENT AIR QUALITY STANDARDS (NAAQS) DUE TO BIOMASS BURNING MORBIDITY AND MORTALITY ATTRIBUTABLE TO PM2.5 AND O3 FROM BIOMASS BURNING REDUCTIONS IN VISIBILITY DUE TO BIOMASS BURNING AND RADIATIVE EFFECTS (DIRECT AND SEMI-DIRECT) OF AEROSOLS AND O3 FROM BIOMASS BURNING IN THE SOUTHEAST. A NOVEL ASPECT OF THIS WORK IS THAT OUR IMPROVED BIOMASS BURNING INVENTORY WILL DISTINGUISH WILDLAND FROM AGRICULTURAL FIRES AND THEREFORE SEPARATELY QUANTIFY HEALTH AND VISIBILITY IMPACTS FOR THESE TWO DIFFERENT FIRE TYPES WHICH IS RELEVANT TO THE ENVIRONMENTAL PROTECTION AGENCY S REGIONAL HAZE RULE AND ALSO TO BALANCING FIRE MANAGEMENT CHOICES AGAINST PUBLIC HEALTH. THIS PROJECT CONTRIBUTES TO THE ACMAP PROGRAM GOALS BY USING NASA SATELLITE PRODUCTS AND PARTICULARLY A-TRAIN PRODUCTS TO EVALUATE AND IMPROVE MODELS OF ATMOSPHERIC CHEMISTRY FOR PURPOSES OF BETTER UNDERSTANDING AIR QUALITY AND CLIMATE FORCING.