Publications by authors named "J Szykman"

Single source contribution to ambient O and PM has been estimated with photochemical grid models to support policy demonstrations for National Ambient Air Quality Standards, regional haze, and permit related programs. Limited field data exists to evaluate model representation of the spatial extent and chemical composition of plumes emitted by specific facilities. New tropospheric column measurements of NO and in-plume chemical measurements downwind of specific facilities allows for photochemical model evaluation of downwind plume extent, grid resolution impacts on plume concentration gradients, and source attribution methods.

View Article and Find Full Text PDF
Article Synopsis
  • The COVID-19 pandemic led to significant reductions in nitrogen oxide (NO) emissions in New York City due to strict lockdowns, with a reported 30% decline above long-term trends.
  • Measurements showed immediate drops in NO levels, up to 36% in Manhattan and between 19%-29% in surrounding areas during spring 2020.
  • Post-lockdown, emissions gradually increased but saw another decline during the second wave of the pandemic, with meteorological conditions affecting NO levels, especially in Manhattan.
View Article and Find Full Text PDF

We present the first NO measurements from the Nadir Mapper of Ozone Mapping and Profiler Suite (OMPS) instrument aboard the NOAA-20 satellite. NOAA-20 OMPS was launched in November 2017, with a nadir resolution of 17 × 13 km similar to the Ozone Monitoring Instrument (OMI). The retrieval of NOAA-20 NO vertical columns were achieved through the Direct Vertical Column Fitting (DVCF) algorithm, which was uniquely designed and successfully used to retrieve NO from OMPS aboard Suomi National Polar-orbiting Partnership (SNPP) spacecraft, predecessor to NOAA-20.

View Article and Find Full Text PDF
Article Synopsis
  • * 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.
View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF