Current Plans for HTAP3 Cooperative Experiments

HTAP3 is taking shape as three sets of experiments (OPNS, MCHgMAP, Fires) with a common base.  All are open to participation from the community.

  • Ozone, Particles, Nitrogen and Sulfur deposition (OPNS): This set of experiments will focus on simulating time series (HTAPv3 emissions) and future policy scenarios (based on GAINS).  A primary focus will be on informing the revision of the LRTAP Convention’s Gothenburg Protocol, including consideration of measures to address methane as a tropospheric ozone precursor.  Another objective will be to provide input to the WMO Measurement Model Fusion-Global Total Atmospheric Deposition (MMF-GTAD) project.  The planning for HTAP3/OPNS is being coordinated by Tim Butler (
  • Multi-Compartment Hg Modeling and Analysis Project (MCHgMAP): This set of experiments will focus on simulating time series and process/source attribution of mercury.  This effort is initially focused on informing the effectiveness evaluation of the Minamata Convention on Mercury and the LRTAP Convention’s Heavy Metals Protocol.  MCHgMAP is being led by Ashu Dastoor (  An overview paper has been drafted and is being prepared for publication.  Work has begun on common input data sets and simulations are expected to begin before the end of 2023.
  • Multi-Pollutant, Multi-Impact Modeling of Fires (Fires): This set of experiments is focused on the impacts of wildfires and agricultural burning on fine particles, ozone, mercury, persistent organic pollutants, and other pollutants of concern.  The objective of the experiments is not only to learn about the various long-range transport impacts of fires, but learn from the effort to bring together different types of models to look across the full range of pollutants associated with fires.  An options paper is being drafted and is open to contributions from the community.  The effort is being led by Cyndi Whaley ( 
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