As inferred from orbital spectroscopic data, Northeast Syrtis Major bears considerable mineral diversity that spans the Noachian-Hesperian boundary despite its small geographic area. In this study we use observations from the High Resolution Imaging Science Experiment, supplemented with Context Camera imagery, to characterize and map the lateral extent of geomorphic units in Northeast Syrtis Ma...

In accordance with the Clean Air Act, the U.S. Environmental Protection Agency (EPA) is currently reviewing its National Ambient Air Quality Standards for particulate matter, which are required to provide an adequate margin of safety to populations, including susceptible subgroups. Based on the latest scientific, health, and technical information about particle pollution, EPA staff recommends e...