UWEC CERCA 2026

NO2 is emitted into the atmosphere as a byproduct of combustion from vehicles, power plants, and industrial processes. Once in the atmosphere, the photochemical reaction of NO2 and volatile organic compounds (VOCs) results in the formation of ozone within the atmosphere. Ground-level ozone is a dangerous respiratory irritant. Because NO2 is the direct emission that leads to the presence of ground-level ozone, it is pertinent to monitor the concentration of NO2 at low altitudes. To better understand the concentration of NO2 at different altitudes around the Lake Michigan waterfront, we are constructing a lightweight cavity enhanced spectrometer capable of measuring NO2 while flown on a drone. The light source is a blue LED emitting in the 300-550 nanometer wavelength range. The light is reflected between two mirrors with 99.998% reflectivity to achieve a sufficiently long path length for measurement. Absorption spectra are measured using an Ocean Optics SR6 spectrometer. Collected spectral data are converted into concentrations using a spectral fitting algorithm that incorporates known Rayleigh scattering values and literature cross sections for five main chemical species. This poster describes our instrument’s integral components, the initial construction of the optical cavity, and the development of a data analysis program in MATLAB.