Nathan is a 6th year PhD student who is developing low-cost greenhouse gas sensors using LEDs. He also works with the mobile lab and helps with field deployments.

i) Low-cost greenhouse gas sensors: There is a need for low-cost sensing solutions in order to achieve real-time, affordable process control and leak detection for the millions of different facilities that emit greenhouse gases. Nathan has been working in collaboration with Jerry Meyer's research group at the U.S. Naval Research Laboratory (NRL). Nathan has tested 2 novel photonic devices from NRL. He demonstrated sub-ppm methane (CH₄) detection using an interband cascade LED coupled with a hollow-core fiber (HCF).

[https://guidingphotonics.com/wp-content/uploads/2021/04/Methanedetectio…]

Recently, Nathan showed that it is possible to detect nitrous oxide (N₂O) at room temperature using an ICLED and resonant cavity infrared detector (RCID), with no discrete optics (i.e., lenses, mirrors). This implies that ICLED-RCID gas sensors can be cheaply mass produced and printed on semiconductor wafers, similar to the sensors in smartphones and household electronics.

ICLED - https://nanoplus.com/products/mid-Infrared-led/2800nm-4000nm-mirled

HCF - https://guidingphotonics.com/mid-infrared-mid-ir-fiber-optic-solutions

RCID - https://opg.optica.org/oe/fulltext.cfm?uri=oe-27-3-3771&id=404599

ii) Sector-wide Seasonal and Diurnal Trends of Methane, Nitrous Oxide, and Ammonia Emissions from Agricultural Waste and Wastewater: The agriculture and waste industries are major sources of greenhouse gases and air pollution. [https://www.globalcarbonproject.org/] Using the group's mobile lab and open-path laser spectrometer technology, Nathan along with the rest of the group, Prof. Jason Ren's group, and Prof. Francesca Hopkins' group at UC Riverside built one of the most comprehensive datasets of facility-level measurements of wastewater treatment plants and dairy farms to date (200 unique farms, 100 unique wastewater treatment plants, a total of 1000+ visits to facilities over 1 year). Some of the goals of the project are to understand what causes emissions and what management practices could reduce emissions and/or improve operational efficiency.

https://sloan.org/programs/research/energy-and-environment/sensors-grants#selected-projects:~:text=greenhouse%20gas%20emissions.-,Mark%20Zondlo,-%2C%20Princeton%20University

https://francescamhopkins.wixsite.com/francescahopkins

https://ren.princeton.edu/

iii) Methane sensing in the Navajo Nation: Nathan deployed a drone-based CH₄ sensor in the Navajo Nation. Nathan is analyzing the data to determine optimal flight paths for gas leak quantification and calibration of infrared cameras.

https://www.princeton.edu/news/2020/06/08/funding-next-big-idea-new-projects-receive-dean-research-innovation-awards?fbclid=IwAR04FqKPO8CPrNz29un01Xq-9tVQ71FW_TTPT1uM70EnrOkZ_FXdfTKhcAU#:~:text=and%20Laura%20Pedrick-,Exposure,-A%20team%20of