Sunday, 11 January 2009
An assessment of air quality in the Houston region by NASA DEVELOP students
Phoenix Convention Center
Increased concentrations of aerosols, specifically those 2.5 micrometers in diameter or less (PM2.5), are detrimental to the health of a community. Houston, Texas lies in a region susceptible to high concentrations of PM2.5 due to increasing pollution from sources including large petrochemical plants and natural sources like Saharan dust. Ground based observations of these aerosols are accurate; however the network of stations does not cover a wide area and therefore accurate aerosol forecasts are difficult. Satellite applications were developed with instruments such as MODIS on Terra and Aqua to potentially provide a method to infer PM2.5 over a wide area. This project examined satellite, aircraft, and surface aerosol observations to investigate the ability to infer surface PM2.5 from satellite Aerosol Optical Depth (AOD) measurements. These issues were addressed in an air quality case study of the Houston region (-93°W to -97° W and 28° N to 32° N) from August to September 2006 to take advantage of measurements acquired during the 2006 TexAQS/GoMACCS study. Peak aerosol events were identified and possible sources of the events were investigated. Comparing Terra MODIS AOD with surface station PM2.5 displayed an r-squared value of 0.7191 on high aerosol concentration days. When Terra AOD measurements were divided by the Planetary Boundary Layer (PBL) height, correlations on high aerosol concentration days improved to 0.8075. CALIPSO curtain plots and HYSPLIT back trajectories were utilized to track aerosol sources and indicated the presence of Saharan dust over the Houston area on August 28, 2006.