MOTIVATION: ATMOSPHERIC PARTICULATE MATTER WITH DIAMETERS SMALLER THAN 2.5 M (PM2.5) IS A POLLUTANT THAT CONTRIBUTES TO THE DEVELOPMENT OF HUMAN DISEASE. SATELLITE-DERIVED ESTIMATES OF SURFACE-LEVEL PM2.5 CONCENTRATIONS HAVE THE POTENTIAL TO CONTRIBUTE GREATLY TO OUR UNDERSTANDING OF HOW PARTICULATE MATTER AFFECTS HEALTH. HOWEVER THESE SATELLITE-DERIVED PM2.5 ESTIMATES ARE OFTEN UNCERTAIN DUE TO A LACK OF INFORMATION ABOUT THE RATIO OF AEROSOL OPTICAL DEPTH (AOD) WHICH THE PRIMARY AEROSOL RETRIEVAL MADE BY SATELLITE INSTRUMENTS AND SURFACE-LEVEL PM2.5. WHILE MODELLING AND STATISTICAL ANALYSES HAVE IMPROVED ESTIMATES OF PM2.5: AOD LARGE UNCERTAINTIES REMAIN IN SITUATIONS OF HIGH PM2.5 EXPOSURE (SUCH AS URBAN AREAS AND IN WILDFIRE-SMOKE PLUMES) WHERE THE HEALTH IMPACTS OF PM2.5 MAY BE THE GREATEST. SURFACE MONITORING NETWORKS FOR CO-INCIDENT PM2.5 AND AOD MEASUREMENTS ARE EXTREMELY RARE EVEN IN THE NORTH AMERICA. THIS PROPOSAL AIMS TO ADDRESS THE PM2.5: AOD CHARACTERIZATION PROBLEM BY DEPLOYING A CITIZEN-BASED MONITORING NETWORK FOR PM2.5 AND AOD AT SPATIAL AND TEMPORAL SCALES NEVER-BEFORE ACHIEVED AND IN REGIONS WITH LARGE EXPECTED GRADIENTS IN PM2.5 (CITIZEN-ENABLED AEROSOL MEASUREMENTS FOR SATELLITES [CEAMS]). CEAMS WILL LEVERAGE NOVEL LOW-COST MEASUREMENT TECHNOLOGY THAT CAN BE DEPLOYED AT SCALES OF 100S TO POTENTIALLY 1000S OF UNITS. WE WILL LEVERAGE SUPPORT FROM EXISTING SUCCESSFUL CITIZEN-SCIENCE NETWORKS TO DEVELOP BEST-PRACTICES THAT ENSURE SUSTAINABILITY AND SUCCESS OF CEAMS. THE PROJECT HAS THREE PRIMARY AIMS: AIM 1 (PROTOTYPE PHASE): CONDUCT A PILOT STUDY OF A LOW-COST SENSOR FOR PM2.5 AND AOD IN A PANEL OF COLORADO CITIZEN-SCIENTISTS. VALIDATE THESE DATA AGAINST STANDARD PM2.5 AND AOD MEASUREMENTS. AIM 2 (IMPLEMENTATION PHASE): EXPAND THE CEAMS NETWORK TO HUNDREDS OF STATIONS ACROSS TWO URBAN AREAS AND ONE RURAL SMOKE PRONE AREA. AIM 3 (IMPLEMENTATION PHASE): USE THE DATA FROM CEAMS TO CONSTRAIN SPATIAL AND TEMPORAL VARIABILITY IN SURFACE PM2.5 AND TO VALIDATE SATELLITE-DERIVED PM2.5 ESTIMATES AT HIGH-RESOLUTION. DEVELOP PARAMETERIZATIONS OF SPATIAL/TEMPORAL PM2.5:AOD VARIABILITY BASED ON HIGH-RESOLUTION EMISSIONS FIELDS METEOROLOGY AND LAND SURFACE FEATURES. INVESTIGATIVE TEAM: JOHN VOLCKENS (PI) COLORADO STATE UNIVERSITY (AEROSOL TECHNOLOGY AND EXPOSURE MEASUREMENT) JEFFREY PIERCE (CO-I) COLORADO STATE UNIVERSITY (AEROSOL MODELING AND SATELLITE ANALYSIS) SHANTANU JATHAR (CO-I) COLORADO STATE UNIVERSITY (AIR POLLUTION EMISSIONS AND ATMOSPHERIC PROCESSING) MARILEE LONG (CO-I) COLORADO STATE UNIVERSITY (SCIENCE COMMUNICATION AND CITIZEN-SCIENCE) BONNE FORD (CO-I) COLORADO STATE UNIVERSITY (AEROSOL MODELING AND SATELLITE ANALYSIS) NOLAN DOESKEN (COLLABORATOR) COMMUNITY COLLABORATIVE RAIN HAIL &SNOW NETWORK (CITIZEN-SCIENCE) RANDALL MARTIN (COLLABORATOR) DALHOUSIE UNIVERSITY (SATELLITE-BASED AIR QUALITY) MIKE BRAUER (COLLABORATOR) UNIVERSITY OF BRITISH COLUMBIA (AIR QUALITY AND GLOBAL HEALTH)