Publications by authors named "Scott Janz"

Urban air pollution disproportionately harms communities of color and low-income communities in the U.S. Intraurban nitrogen dioxide (NO) inequalities can be observed from space using the TROPOspheric Monitoring Instrument (TROPOMI).

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Article Synopsis
  • Understanding local-scale ozone formation variability is essential for effective mitigation strategies.
  • The study analyzes airborne and ground-based measurements of formaldehyde and nitrogen dioxide during high-ozone days in May-August 2018 in New York City and Baltimore/Washington D.C.
  • Increased formaldehyde levels and urban-centered nitrogen dioxide spikes imply a shift toward a more reactive ozone production regime, suggesting greater effectiveness of nitrogen dioxide reduction strategies on days when ozone levels are high.
  • Weather conditions, like temperature and wind patterns, also influence these ozone levels, with different effects observed between NYC and BAL/DC.
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  • * The study used a Regional Chemical and Transport Model (REAM) to compare simulated NO data with actual measurements from aircraft, satellites, and ground instruments during the DISCOVER-AQ campaign in 2011 in the Baltimore-Washington area.
  • * While daytime model results generally matched observed NO concentrations well, nighttime data showed significant inaccuracies that could be improved by adjusting the model's vertical mixing parameters; also, higher-resolution simulations revealed inconsistencies in urban NO measurements.
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The Lake Michigan Ozone Study 2017 (LMOS 2017) was a collaborative multiagency field study targeting ozone chemistry, meteorology, and air quality observations in the southern Lake Michigan area. The primary objective of LMOS 2017 was to provide measurements to improve air quality modeling of the complex meteorological and chemical environment in the region. LMOS 2017 science questions included spatiotemporal assessment of nitrogen oxides (NO = NO + NO) and volatile organic compounds (VOC) emission sources and their influence on ozone episodes; the role of lake breezes; contribution of new remote sensing tools such as GeoTASO, Pandora, and TEMPO to air quality management; and evaluation of photochemical grid models.

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Airborne and ground-based Pandora spectrometer NO column measurements were collected during the 2018 Long Island Sound Tropospheric Ozone Study (LISTOS) in the New York City/Long Island Sound region, which coincided with early observations from the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) instrument. Both airborne- and ground-based measurements are used to evaluate the TROPOMI NO Tropospheric Vertical Column (TrVC) product v1.2 in this region, which has high spatial and temporal heterogeneity in NO.

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NASA deployed the GeoTASO airborne UV-Visible spectrometer in May-June 2017 to produce high resolution (approximately 250 × 250 m) gapless NO datasets over the western shore of Lake Michigan and over the Los Angeles Basin. The results collected show that the airborne tropospheric vertical column retrievals compare well with ground-based Pandora spectrometer column NO observations (r=0.91 and slope of 1.

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Houston, Texas is a major U.S. urban and industrial area where poor air quality is unevenly distributed and a disproportionate share is located in low-income, non-white, and Hispanic neighborhoods.

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During the May-June 2016 International Cooperative Air Quality Field Study in Korea (KORUS-AQ), light synoptic meteorological forcing facilitated Seoul metropolitan pollution outflow to reach the remote Taehwa Research Forest (TRF) site and cause regulatory exceedances of ozone on 24 days. Two of these severe pollution events are thoroughly examined. The first, occurring on 17 May 2016, tracks transboundary pollution transport exiting eastern China and the Yellow Sea, traversing the Seoul Metropolitan Area (SMA), and then reaching TRF in the afternoon hours with severely polluted conditions.

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Article Synopsis
  • The launch of new geostationary pollution monitoring satellites will significantly enhance air quality measurement across North America, East Asia, and Europe, aiming for improved atmospheric observation capabilities.
  • The paper showcases how NASA's GeoTASO instrument, along with ground-based and low Earth orbit observations, has provided detailed air quality data for Seoul and Los Angeles, revealing different patterns in nitrogen oxide (NO) levels throughout the day.
  • Detailed diurnal behavior differences were noted, highlighting how urban areas influence air quality, with GeoTASO's findings serving as a key validation resource for upcoming satellite missions like TEMPO.
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