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Examining Neighborhood Scale Variability of Co-incident PM2.5 and AOD Measurements: Results from Citizen Enabled Aerosol Measurements for Satellites (CEAMS)
MICHAEL CHEESEMAN, Bonne Ford, John Volckens, Jeffrey R. Pierce, Eric Wendt, Casey Quinn, Christian L'Orange, John Mehaffy, Shantanu Jathar, Marilee Long, Zoey Rosen, Colorado State University, Fort Collins, CO
Abstract Number: 519
Working Group: Satellite-Data and Environmental Health Applications
Abstract
Exposure to ambient fine particulate matter (PM2.5) is associated with adverse health impacts. Studies have generally relied on surface monitoring networks to quantify population exposure to PM2.5 but these estimates are uncertain due to large spatial gaps between monitors. Satellite observations of aerosol optical depth (AOD), a column-integrated measure of light extinction due to aerosols, have been increasingly used to estimate surface PM2.5 and fill the spatial gaps of monitoring networks. However, satellite-derived PM2.5 estimates have large uncertainties due, in part, to a lack of information on the ratio of PM2.5 and AOD. More co-incident PM2.5 and AOD measurements are needed to reduce the uncertainties in satellite-derived PM2.5. Thus, we present concurrent PM2.5 and AOD measurements from a high density network of low-cost samplers developed by the Citizen-Enabled Aerosol Measurements for Satellites (CEAMS) project. The sampler used, called the Aerosol Mass and Optical Depth (AMOD) sampler, is a low-cost, portable instrument capable of taking autonomous, high-quality measurements of AOD and PM2.5 simultaneously. The AMOD includes a set of four optically filtered photodiodes for multi-wavelength (440, 500, 675, and 870 nm) AOD, a Plantower PMS5003 sensor for time-resolved optical PM measurements, and a pump and cyclone system for time-integrated gravimetric filter measurements of particle mass. The AMOD uses autonomous sun alignment to provide semi-continuous AOD measurements. We present validation results using co-located AMOD and standard monitoring measurements (i.e. AERONET sun photometers and Federal Equivalent Method PM2.5). We also present data from pilot campaigns in Colorado that captured both winter and summer conditions, stagnation events, and wildfire smoke events. We quantify the bias of satellite-derived PM2.5 due to its reliance on AOD only captured during satellite-overpass times. And, finally, we investigate (1) neighborhood scale differences in nighttime PM2.5 and (2) the role of elevation and overnight pooling of pollution.