First Advisor

Linda George

Term of Graduation

Spring 2021

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Environmental Science and Management


Environmental Science and Management




Diesel motor exhaust gas -- Oregon -- Portland -- Measurement, Diesel motor exhaust gas -- Oregon -- Portland -- Analysis, Cluster analysis, Fuzzy sets



Physical Description

1 online resource (viii, 74 pages)


Exposure to diesel emissions causes a range of health effects throughout the body, impairing; respiratory, cardiovascular, central nervous, renal, and cognitive systems. Diesel particulate matter (DPM) in Portland, Oregon is prevalent due to the layout of highly trafficked roadways, rail lines, and marine ports exposing a dense population to high levels of exhaust pollution. These high concentrations of ambient diesel emissions disproportionately impact minority and low-income populations.

Ground-based monitoring and modeling are two ways to assess ambient DPM. However, there are uncertainties in modeled DPM due to knowledge gaps in emissions inventories as well as lack of model validation against ground-based measurements. We propose a framework for efficient assessment of localized diesel emission sources, and model validation.

Sources of diesel identified as having the largest uncertainty in previous modeling studies were assessed for activity data and emissions were sampled for each main source type. We monitored for a range of traffic related air pollutants such as Black carbon and Nitrogen Oxides in two communities. These measurements will enable us to assess dispersion models, and better characterize DPM sources that are impacting the health of these communities. Fuzzy cluster analysis's applicability in air quality is shown through several studies but not yet for diesel identification. Fuzzy Cluster analysis was investigated as a potential tool for simplified source characterization. We demonstrate its practical use and discuss the opportunities and challenges of interpreting fuzzy clustering output.

In summary we present a suite of tools, accessible to most municipalities in the US, that can be used to fill in knowledge gaps or validate models to help communities to better understand and plan to mitigate their health risk from exposure to DPM.


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