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Dissertation
Assessing the impacts of airborne particulate matter from plastic burning and personal care products
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2026
DOI: 10.25820/etd.008335
Abstract
Airborne fine particulate matter (PM) is linked to many negative human health effects, such as cardiovascular and respiratory issues. To effectively manage air quality to protect human health, it is necessary to identify and evaluate the impact of PM sources in the atmosphere. This dissertation examines the impact of two globally important yet under-assessed sources of PM, plastic burning and personal care products, via field-based assessments. Plastic burning, a globally important source of PM, is examined by the quantification of 1,3,5-triphenylbenzene (TPB), an aromatic compound used as a molecular tracer for PM produced via plastic burning. Thermal desorption gas chromatography mass spectrometry (GC-MS) is applied for the quantitation of TPB in PM samples collected in urban and rural areas in the USA and Bangladesh. The impacts of plastic burning in the USA were estimated to range from 0.3–3% of PM for most locations, and up to 7% for an urban site during the winter. In Bangladesh, estimated plastic burning impacts on PM were estimated to range from 0.6–15% of PM. Plastic burning impacts on PM tended to be greatest in urban areas, with lower concentrations in sub-urban areas, and non-detects occurring in only one extremely remote location. These results suggest that plastic burning is a widespread source of ambient PM, with potentially large impacts in urban areas where plastic is commonly burned.
Gas phase compounds from personal care products, like decamethylcyclopentasiloxane (D5), can react in the atmosphere to form secondary organic aerosol (SOA) particles. While this process has been demonstrated in the laboratory, the extent of this process in ambient air is unknown. The gas-particle distribution of the major oxidation product of D5, D4TOH, was examined for the first time in ambient air. Field measurements in New York City (NYC) during the summer of 2022 revealed that D4TOH was found to be present mostly in the gas phase (87% on average), with a minority in the particle phase (13%). Adsorptive and absorptive partitioning models predicted that 99% of D4TOH in the particle phase was due to adsorption. The linear relationship between the logarithm of the partition coefficient and inverse temperature enabled predictions in gas-particle partitioning with temperature. While D4TOH is mostly in the gas phase during summertime in NYC, it is expected to be primarily in the particle phase below 15.5oC making it a potentially larger contributor to SOA in other seasons. Additionally, this study demonstrates that correction for positive sampling artifacts is essential to the accurate determination of accurate D4TOH gas and particle fractions because this semi-volatile material can readily adsorb to quartz fiber filters.
PM organic carbon in NYC was apportioned to its sources by chemical mass balance modeling using molecular tracers. Primary sources included several types of fossil fuel combustion including diesel engines, gasoline engines, and ship emissions, which contributed 4-18%, averaging 8% of PM. Biomass burning contributed 2% of organic carbon on average, and reached a maximum of 14%. Biogenic SOA tracers from isoprene, monoterpene, and sesquiterpene SOA were consistently observed, with average organic carbon contributions of 3%, 5%, and 2%, respectively. Anthropogenic SOA derived from aromatic volatile organic compounds averaged 6% of PM organic carbon. On average, the majority (71%) of PM organic carbon was not apportioned to known primary and secondary sources, and is expected to mainly consist of additional SOA, especially from anthropogenic precursors.
Overall, the results from this dissertation demonstrate that plastic burning and personal care products are consistent sources of PM, with varying impacts. Plastic burning can be a major contributor to PM in polluted urban areas where plastic burning is common but is a minor source elsewhere. Personal care products are expected to partition more to the particle phase in NYC in colder temperatures due to shifts in gas-particle partitioning, which warrants further investigation. The results of NYC field campaign show that while personal care products can contribute to PM in the summertime, the relative contribution is low compared to other primary and secondary sources. Because plastic burning and personal care product-derived SOA can be tracked through molecular tracers readily measured by GC-MS, they should be included in air quality assessments elsewhere to broaden our understanding of their impacts on ambient PM, particularly as they both constitute potentially controllable anthropogenic sources.
Details
- Title: Subtitle
- Assessing the impacts of airborne particulate matter from plastic burning and personal care products
- Creators
- Josie Welker
- Contributors
- Elizabeth A. Stone (Advisor)Keri C. Hornbuckle (Committee Member)Scott K. Shaw (Committee Member)David Cwiertny (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Chemistry
- Date degree season
- Spring 2026
- DOI
- 10.25820/etd.008335
- Publisher
- University of Iowa
- Number of pages
- xvii, 125 pages
- Copyright
- Copyright 2026 Josie Welker
- Grant note
- I would like to extend gratitude to the following funding sources that have supported my work: NSF (Grant No. AGS-2028764) and the University of Iowa Graduate College.
- Language
- English
- Date submitted
- 04/28/2026
- Description illustrations
- illustrations, tables, graphs
- Description bibliographic
- Includes bibliographical references (pages 106-125).
- Public Abstract (ETD)
The air we breathe includes tiny particles called particulate matter (PM). PM is harmful to our lungs, hearts, and brains, so finding ways to reduce PM is important to keeping people healthy. There are many sources of PM in the air, including fires, motor vehicles, and plants. Identifying sources of PM and assessing their impacts helps determine which sources we need to reduce. The goal of this research is to evaluate the impacts that plastic burning, and personal care products have on PM. For this research, gas and PM samples from field sites around the world were tested in the laboratory for chemicals that can help us identify PM sources. Results showed that plastic burning can be a major source of PM in some megacities, with a lesser impact in remote and suburban locations. Personal care products release gases into the air that can become particles. In New York City, the products from personal care products were mostly gases in the summer, rather than particles. Personal care products may contribute more to PM in other seasons when cooler temperatures cause gases to form PM. This information can help us create plans to improve air quality in the future.
- Academic Unit
- Chemistry
- Record Identifier
- 9985177373902771
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