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In recent decades, overall particulate matter (PM) concentrations have declined in the U.S. as a result of regulatory policies. However, in several basins in the western U.S., wintertime PM concentrations have not experienced similar levels of improvement. This suggests that current regulatory actions may not be effectively targeting the appropriate precursor emissions and that there is a gap in our understanding of how the unique boundary layer meteorology and complex chemical processes interact to produce these elevated PM conditions. In addition, the PM precursor emissions are co-emitted with greenhouse gases (GHGs) that are of interest to urban policy makers and for which cities have active mitigation plans in place. It is vital to understand how the atmospheric chemistry, boundary layer meteorology, and GHG gas mitigation plans will impact air quality in the future.

AQUARIUS (Air Quality in the Western US) workshop on September 25-26, 2019 in Salt Lake City, UT will focus on a future aircraft campaign in the winter of 2022/2023 to investigate wintertime PM in mountain basins of the western U.S. 

 The goals of the workshop will be to:

  • Identify measurements and the robust critical core airborne capabilities needed to enhance the fundamental understanding of wintertime PM within persistent cold air pools (PCAPs) including the oxidation chemistry, aerosol thermodynamics and interactions between atmospheric chemistry and meteorology within wintertime PCAPs.
  • Identify measurements needed to constrain the emission ratios between PM precursors and GHGs across western basins with different levels of urbanization and agriculture.
  • Identify emission inventories in need of constraint to improve and evaluate chemical transport models of wintertime PCAPs.
  • Organize the community of researchers to develop a plan of action to coordinate efforts to address these needs.

After the workshop, the organizing committee will write a white paper outlining the scope and plan for the future aircraft and ground-based field campaign.

This workshop is jointly funded by the NSF Atmospheric Chemistry Program (Award Number 1912664) and the NOAA Atmospheric Chemistry, Climate and Carbon Cycle Program (Award Number NA19OAR4310078).


The workshop proposal outlining the scientific rationale for the AQUARIUS project can be viewed here:


Workshop Presentations

Presentations from the AQUARIUS workshop are available here:

Workshop Presentations

Last Updated: 4/30/21