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Sources and Impacts of Atmospheric NH3: Current Understanding and Frontiers for Modeling, Measurements, and Remote Sensing in North America
Citation:
Zhu, L., D. Henze, J. Bash, K. Cady-Pereia, M. Shephard, M. Luo, AND S. Capps. Sources and Impacts of Atmospheric NH3: Current Understanding and Frontiers for Modeling, Measurements, and Remote Sensing in North America. Current Pollution Reports. Springer, New York, NY, 1(2):95-116, (2015).
Impact/Purpose:
The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mission to protect human health and the environment. AMAD’s research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the Nation’s air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
Ammonia (NH3) contributes to widespread adverse health impacts, affects the climate forcing of ambient aerosols, and is a significant component of reactive nitrogen, deposition of which threatens many sensitive ecosystems. Historically, the scarcity of in situ measurements and the complexity of gas-to-aerosol NH3 partitioning have contributed to large uncertainties in our knowledge of its sources and distributions. However, recent progress in measurements and modeling has afforded new opportunities for improving our understanding of NH3 and the role it plays in these important environmental issues. In the past few years, passive measurements of NH3 have been added to monitoring networks throughout the USA, now in place at more than 60 stations, while mobile measurements aboard aircrafts and vehicles have provide detailed observations during several recent field campaigns. In addition, new remote sensing observations from multiple satellite instruments have begun to provide vast amounts of NH3 observations throughout the globe. These sources of information have collectively driven new air quality modeling capabilities, by revealing deficiencies in current air quality models and spurring development of mechanistic enhancements to models’ physical representation of the diurnal variability and bidirectional nature of NH3 fluxes. In turn, these advanced models require further observational constraints, as existing NH3 measurements are still limited in spatiotemporal coverage. We thus evaluate the potential value of a new geostationary remote sensing instrument (GCIRI) for providing constraints on NH3 fluxes through multiple Observing System Simulation Experiments (OSSEs).
