By Jean Andrews
Physics & Astronomy
From observing ozone phenomena to building micro-scale devices, senior Helen Cothrel ’15 HTC Physics, explores her environment to the extreme.
This summer she is working at the David Skaggs Research Center in Boulder, CO, to study the Earth’s ozone layer. She received funding through an Ernest F. Hollings Scholarship, a two-year appointment with the National Oceanic and Atmospheric Administration’s Office of Education.
The title of her NOAA project is “Summertime Ozone Measurements in the Colorado Front Range.” She’s looking at summertime ozone exceedances in Colorado (i.e. ozone episodes above the 75 ppb standard), and possible correlations between high ozone levels and specific ozone precursors. “Identifying ozone exceedances that correlate with a certain precursor would allow us to identify what circumstances led to an exceedance, such as forest fires or gas and oil well activity,” she wrote in her project abstract.
“Surface ozone data has been collected in Erie, Colorado, since July 2008. Ozone, O3, is an atmospheric compound which results from sunlight-driven chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs). Ozone is a critical part of the troposphere because it drives photochemical reactions and regulates oxidation capacity. Additionally, ozone is a greenhouse gas, and it can be a harmful air pollutant. Ozone is most harmful in the lower atmosphere, where it contributes to photochemical smog and has negative effects on flora and fauna. This collection of properties makes ozone a compound of great interest to researchers.”
“The purpose of this study is to identify long-term trends of surface ozone in Erie, Colorado, and to characterize high-ozone episodes. High ozone is almost exclusively observed in the summer, when the abundance of sunlight contributes to push the ozone level over the EPA’s national ambient air quality standard (NAAQS) of 75 ppb. Seasonal trends of ozone are established, and ozone levels are analyzed with regard to ozone precursor pollutants, such as carbon monoxide (CO) and methane (CH4). Also, ozone exceedances are analyzed versus dominant wind direction, to establish the possible contributions to high-ozone from recent gas and oil industry activity to the northeast of the Erie, Colorado, site. It is observed that ozone exceedances show a strong correlation with wind direction, particularly with the northeast wind sector, as expected. Strong correlations are observed between temperature, CO, and CH4 and ozone.”
After returning to Athens at the end of the summer, Cothrel plans to switch gears and work at the nanoscale. She’ll use microscale devices with photolithography to investigate the properties of nanostructures such as quantum dots. She has been developing a photolithography procedure to produce micron scale metallic devices to ultimately use in the study of nanostructured materials. This has involved significant effort to identify the optimal parameters to produce working device structures. In the next stage of the project Helen will be employing various optical spectroscopy and imaging techniques to study new materials and nanostructures including arrays of colloidal quantum dots, quantum wires, and hybrid structures. The goal is to help study energy transfer in these materials.
Being a well-rounded scientist means having a sense of wonder for things outside your chosen field. Cothrel found time this summer to explore the Colorado landscape and hike with her family when they visited. Other relaxing activities included playing video games, going to a local coffee shop to hang out and reading novels like ‘The Lord of the Rings.’