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VOC to NOx relationships and Impacts of Smoke on Ozone in the Wasatch Front

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  • Principal Investigator:  Dr. Dan Jaffe (University of Washington)
  • Study Period: July 1, 2024 – August 30, 2025.
  • Funded by Science for Solutions Research Grant: $71,138
  • DAQ Contact: Chris Pennell ([email protected])

Meeting the O3 standard in the Wasatch Front will require emission reductions from local sources and careful tracking of non-local sources, such as wildfires. To make the best decisions on emission reductions, it is essential to understand the regional VOC-NOx sensitivity. In this project, we will use existing and new observations to:

  1. Identify smoke days for 2018-2024 and identify O3 exceedance days that are exacerbated by wildfire smoke; and…
  2. Examine the formaldehyde (CH2O) to NO2 ratio (FNR) across the region using both in- situ observations and new satellite data to understand the O3 sensitivity to NOx and VOCs.

For the first goal, we will use satellite data plus surface PM2.5 to identify smoke days and understand the frequency and impacts of wildfires on both PM2.5 and O3 for multiple sites in the Wasatch Front. We will then apply Generalized Additive Modeling to the data for the 2018- 2024 time period to estimate the wildfire contribution to the O3 maximum daily 8-hour average (MDA8). The GAMs will be applied to 4 or more sites within the Wasatch Front. 

For the second goal, we will use existing in-situ formaldehyde and NO2 data from several sites, new observations data obtained in 2024 and new high-resolution data from the TEMPO satellite instrument. Combining these will give important insights into the VOC-NOx sensitivity for O3 production across a wide region of the Wasatch Front. 

These two goals will provide important policy relevant insights into the processes that control high O3 days in the Wasatch Front.

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