Atmospheric_Microplastics_STL_2023to2024

GENERAL INFORMATION

Overview: This README explains the full directory of research files from a 2023-2024 research project in the Hasenmueller Environmental Geochemistry & Hydrology Lab at Saint Louis University exploring microplastics in atmospheric deposition in the St. Louis, MO area. Samples were taken near Deer Creek at the Litzsinger Road Ecology Center and on Saint Louis University's campus from 2023-2024. The project was completed by graduate researcher Natalie Hernandez under the guidance of Dr. Elizabeth Hasenmueller. FTIR data were collected in collaboration with Dr. Susanne Brander and colleagues at Oregon State University. 

Title of Folder: Atmospheric_Microplastics_STL_2023to2024

Created: 2025/10/07

Last Updated: 2026/08/12 by Natalie Hernandez

Contact: 
	
	Name: Elizabeth Hasenmueller
	Email: elizabeth.hasenmueller@slu.edu
	Institution: Saint Louis University
	Department: Earth, Environmental, and Geospatial Science
	Funding: Litzsinger Road Ecology Center, USGS/MWC, Saint Louis University
	
Related Publications: 

Hernandez, N.F., Youmans, D., Brander, S., Hasenmueller, E.A. (2026). “Urbanization and humidity impact atmospheric deposition of anthropogenic microparticles (including microplastics) in a humid subtropical city”. Atmospheric Environment, 122294. https://doi.org/10.1016/j.atmosenv.2026.122294. 

Hernandez, N.F., Youmans, D., Brander, S., Hasenmueller, E.A. “Urbanization and humidity impact atmospheric deposition of anthropogenic microparticles (including microplastics) in a humid subtropical city”. T126: Urban Geochemistry. Oral presentation at the 2025 Fall Meeting, Geological Society of America, San Antonio, TX, October 19-22, 2025. 

Hernandez, N.F. (2025). "MICROPLASTIC DEBRIS TRANSPORT IN AN URBAN WATERSHED ACROSS MULTIPLE FLOW CONDITIONS AND ENVIRONMENTAL COMPARTMENTS" (Dissertation). St. Louis, MO: Saint Louis University.

Hernandez, N.F., Hasenmueller, E.A. “Atmospheric deposition varies spatially and temporally as a source of microplastics to urban environments”. H53R: Plastics in the Hydrosphere: From Source to Sink III. Poster presentation at the 2023 Fall Meeting, American Geophysical Union, San Francisco, CA, December 11-15, 2023. 

DIRECTORY ORGANIZATION 

	Atmospheric_Microplastics_STL_2023to2024/
		Data_Sheets/	
		Methodology/
		Microplastic_Photos/
			SampleIDLabeledFolders/
		Microplastic_Spectra/

Directory Meaning: 

	- Data_Sheets: This folder contains Excel files for each dataset of the project, including field sampling data and microplastic data. Note that the summary data file is intended for quick reference, and data sheets separated by data type contain more detailed information for each dataset. 
		- File Naming Convention: Atmospheric_DataType_Data
		- Example: Atmospheric_Field_Data contains data from field sampling for the project. 
	- Methodology: This folder contains PDF files of methodologies used for microplastics sample processing. 
		- File Naming Convention: Concise method title
		- Example: Atmospheric_Deposition_Sampling is the procedure for sampling atmospheric deposition in the field. 
	- Microplastic_Photos: This folder contains pictures of identified microparticles taken with an AmScope Trinocular Stereo Microscope equipped with a camera.  
		- File Naming Convention: Folder name YYMMDD-YYMMDD SiteCode A; photo name YYMMDD-YYMMDD SiteCode A ParticleNumber
		- Example: 230511-230515 DCL A 5 is the 5th particle found in a sample from Deer Creek taken 5/11-5/15 2023. Note that some photo titles have additional relevant information such as 'x3mag' indicating 30x magnification rather than the standard 45x magnification. Folders may contain some extra photographs (particles of macro size > 5mm, or other photos of interest beyond the primary published dataset). 
	- Microplastic_Spectra: This folder contains spectra files for the subset of microparticles analyzed with a Thermo Fisher Scientific Nicolet iN5 microFTIR (attenuated total reflectance across wavenumbers 4000-650 nm with a germanium crystal).
		- File Naming Convention: Samples use SiteCodeWeekCode-SlideNumber, Blanks use DateCodeBlankType-SlideNumber. For interpretation of week code used to shorten sample IDs, reference field datasheet. 
		- Example: Sample example DCL3-1 is Deer Creek, week 3, slide 1; Blank example 905FBA-1 is Field Blank taken 9/5, slide 1
		- Note that additions of "A1", "A2", etc. for some files indicate if the spectra is from one of multiple attempts to run the particle with FTIR.

Relationship between Directories and Files: The Sample ID (YYMMDD-YYMMDD SiteCode A) is universal through all datasets, including photos and other data types. Simplified sample IDs using a week code, used for spectral data, are interpretable by referencing the field datasheet. 

METADATA

Documentation: Every data sheet includes general metadata. Column names and units are explained in a data dictionary, or have the format of variable name in row 1 and unit in row 2 (e.g., in the simplified summary file), with one exception - we point to the original metadata provided with air quality and meteorologic datasets collected from other sources. Simple protocols are described within data sheets. Lengthier procedures are included in the directory in the Methodology folder. Note that column names typically use title case with no spaces, while tab names and file names typically use underscores. 

METHODOLOGICAL INFORMATION

Description of research methods used is provided in the 'Methodology' folder. Descriptive information is also provided in the associated publications and references therein.