Infusing NASA satellite data to model air-quality for Southeast United States: A wildfire, aerosol transport, and respiratory health case study

Air pollutants from wildfires have adverse impacts on air quality and public health. Fine particulate matter (PM2.5) from smoke has been found to cause respiratory disorders in susceptible populations. The Okefenokee fires, which occurred in South Georgia and North Florida from spring to summer of 2007, biased the ambient air quality measurements in Birmingham, AL which ultimately led to the reclassification of the period between May 14 and June 3, 2007 as an “exceptional event”. The main objectives of this study are to derive PM2.5 values from satellite imagery, analyze the flux of smoke from the Swamp, and asses the health impacts from the fires.

Daily Aerosol Optical Depth (AOD) Level 2 product from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Aqua and Terra satellites with 10x10 km spatial resolution was used to evaluate air quality in areas lacking PM2.5 monitors. The MODIS AOD Level 2 product was correlated with the Environmental Protection Agency's (EPA) ground-based PM2.5 observations to provide information about which days during the research period had high aerosol loading in the atmosphere over Jefferson County. True-color composites created from MODIS Level 1B Radiance data, archive synoptic meteorological charts, and forward trajectory runs from NOAA's HYSPLIT model were used to qualitatively assess the transport of smoke aerosols into Jefferson County. PM2.5 and MODIS AOD values from other years for the same research area and period were examined to show the significance of aerosol loading during late spring/early summer 2007. The GOES East Aerosol/Smoke Product (GASP) was used to analyze and predict smoke flux which helps to differentiate between local versus regional sources of pollution. Asthma emergency room outpatient data from 2004 to 2007 from the University of Alabama at Birmingham Lung Health Center were used to identify the anomalies in asthma visits in May and June of 2007 compared to previous years and was also correlated with PM2.5 observations. The satellite data, ground-based aerosol measurements, and flux analysis represent that respiratory health hazards are a function of extreme aerosol loading events, such as the 2007 Okefenokee fires. Onset of asthma symptoms and increased number of emergency room visits occurred immediately after the fire period. This study will be beneficial to the Jefferson County Department of Health to assess the contribution of regional transport of aerosols into the county versus locally produced aerosols. In addition, a set of rules or metrics can be developed to assist in public health issues from future fire events.