MISR Satellite Observations of Environmental Factors Affecting Human Health in California, from the San Joaquin Valley to the Salton Sea

Ground-based observations of pollutants and concentrations of particulate matter (PM), especially small particles designated PM_2.5, are the gold standard in studies of environmental impacts on human health. However, because monitoring stations are costly, they typically provide only limited spatial coverage, especially in rural areas such as California's San Joaquin Valley, which includes the cities of Fresno and Bakersfield. Likewise, long term monitoring of the shoreline of the endorheic Salton Sea in southern California, between the Coachella and Imperial Valleys, is important for understanding the potential for increased local dust production that can directly impact the health of residents of the surrounding communities.

We will demonstrate how data from the Multi-angle Imaging SpectroRadiometer (MISR) instrument that has been flying on NASA's Terra Earth Observing System satellite since early 2000 can be used to provide estimates of surface PM2.5 for the San Joaquin Valley. The 4.4 km x 4.4 km spatial resolution of the PM_2.5 information data is fine enough to be able to resolve local differences in PM loading that may be important for understanding the health effects of pollution in the region. MISR data at full 275 m x 275 m resolution was also used to track the decrease in the surface area of the water in the Salton Sea, showing that the exposed land area has increased by 43 km² over 13 years of observations, with a very linear trend. Due to the environmental conditions within the Salton Sea itself, it is likely that this additional surface includes potentially high concentrations of toxic chemicals that can be picked up in blowing dust. Continuation of the trend to 2020 would lead to an additional exposure of 23 km² (9 mi²), an area the size of the city of Williamsburg, VA. However, recently enacted water use agreements are likely to increase the rate at which the Salton Sea is evaporating. Finally, we will discuss future NASA instruments that will provide new information allowing for better estimates of surface PM from space and improve studies of air pollution on human health.