Community Partner

Meenakshi Rao, Oregon Department of Environmental Quality

First Advisor

Linda George

Date of Award

Winter 2022

Document Type


Degree Name

Master of Environmental Management (MEM)


Environmental Science and Management




Diesel motor exhaust gas -- Oregon -- Portland Metropolitan Area -- Measurement, Air -- Pollution -- Oregon -- Portland Metropolitan Area




Air pollution from diesel combustion is a well-known and serious problem which adversely impacts human and environmental health throughout the world. One of the primary pollutants of concern from diesel combustion are the solid particles formed as a byproduct of the incomplete combustion of the diesel, also known as diesel particulate matter. As a result of the ubiquitous use of diesel-fired engines in urban environments, understanding the transport of diesel particulate matter from the exhaust is paramount in assessing human exposure to this toxic pollutant. Air dispersion modeling is one method to study how diesel particulate matter is transported and where the greatest risk of exposure can be found.

Emissions of diesel particulate matter were modeled for the Portland metropolitan area by the Oregon Department of Environmental Quality (DEQ) using the CALPUFF model. Diesel particulate matter was modeled in 2005 (PATA) and again in 2012 (PATS) by the DEQ. The purpose of this study is to update and enhance the model framework from these two studies to improve the current understanding of exposure to diesel particulate matter in the Portland area. Updates to the model framework include the implementation of a more current meteorological dataset and emissions inventory, and enhancements include using a higher resolution meteorology, and the addition of a new source category, truck distribution centers.

Model concentrations from this study underwent a quality assurance (QA) and validation process using ambient monitored black carbon data from monitors in the Portland area. Results of the QA and validation process showed that the enhancements made for this study resulted in modeled concentrations that aligned closer to the monitored concentrations relative to the 2005 and 2012 studies. Using the updates to the model framework from this study, the DEQ can continue to develop future iterations of the PATS study to better understand diesel particulate matter exposure in the Portland area.


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A project report submitted in partial fulfillment of the requirements for the degree of Master of Environmental Management.

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