Category: Mobile Source Emissions Current & Ongoing Studies

Reducing automobile emissions has been a central component of the state’s plans to improve air quality. The start cycle of vehicles is known to have increased emissions of hydrocarbons (HC) and carbon monoxide (CO) because the engine uses an enriched fuel mixture to avoid misfires due to condensation on the cylinder walls. The following studies quantify the impact of different vehicle starting methods at low temperatures on Utah’s wintertime air quality.

Current & Recently Completed Studies

Heavy Duty Vehicles

Winter Measurements of Heavy-duty Vehicles to Characterize the Cold Temperature Effectiveness of Selective Catalytic Reductions Catalyst in Controlling Oxide of Nitrogen Emissions

The Salt Lake City region in Utah experiences periods of high particulate levels in the winter months due to the combination of its topography, winter atmospheric inversions and local emissions. Secondary nitrate particles comprise the dominant fraction of the particles in these episodes and are the result of the reaction of oxides of nitrogen (NOx) with ammonia. A significant fraction of NOx emissions in the Salt Lake City area are produced by heavy-duty vehicles operating in or traveling through the area on the interstate highway system. This study will measure wintertime NOx emissions from local heavy-duty vehicle activity in order to improve Utah DAQ emissions inventory estimates and better inform policy.

  • Gary Bishop (University of Denver)
  • Funded by Science for Solutions Research Grant: $52,000
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Car Exhaust Photo from Unsplash Matt Boitor

Ammonia Emission Assessment from Diesel and Gasoline Engines under Utah Specific Conditions

To better understand the contribution of automobiles to Utah ammonia emissions, tailpipe ammonia (NH3) measurements will be taken in laboratory and on-road settings for an array of diesel and gasoline vehicles representative of Utah’s vehicle fleet.

  • Principal Investigators: Randal S. Martin (USU), Joe Thomas (UDAQ), John Sohl (WSU)
  • Funded for: $59,958
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