Investigation of climate change impacts on respiratory health risk in the United States with NASA Satellite Measurements

Climate change poses one of the greatest challenges to public health security and threatens humans around the world with more extreme weather and climate events, such as heat waves, drought, and wildland fires. In addition to the natural hazards, the warming spring temperature can affect plant phenology, causing some plants to produce pollen earlier, which may increase respiratory disease risks with longer allergy seasons and higher pollen counts. Pollen allergy is one of the major public respiratory health issues in the United States, so it is very important to investigate the impacts of climate change on pollen allergy risks. The ground stations for pollen monitoring are sparsely distributed, which set limits to studying the spatial patterns of pollen season changes. This study exploits the satellite remote sensing measurements from the NASA Earth Observing System (EOS) missions to investigate plant phenology changes. Maps of land surface temperature trends and plant phenology trends are generated through time series analysis of the Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data products. Statistical analysis of land surface temperature shows warming trends in the western and eastern United States. The phenology data demonstrate significant diverse responses of plant phenology changes in the continental United States, with some regions such as northeastern USA experiencing early greenup with a trend of more than 1 day earlier per year, while some regions in the central USA do not show significant changes, and some regions show later greenup trend. Overall, the growth periods in northeastern USA and parts of northwestern USA have considerably lengthened, while the growth periods in the middle region of the USA have become shorter. These trend maps can provide support for the evaluation of respiratory disease risks caused by climate change. The patterns of phenology trends are consistent with EPA pollen season reports from selected places. Quantitative comparison with pollen data from ground stations will be conducted. This investigation provides scientific evidence and knowledge of respiratory disease risk caused by climate change in the USA.