<p>In this work, two overarching global crises are addressed with an engineering lens; the COVID-19 pandemic and climate change. Regarding the latter, an investigation is completed into the fluxes of CO2 in the wake of a simple wind farm for identification of potentially beneficial siting of Direct Capture of CO2. In this analysis, large-eddy simulations are used to quantify scalar entrainment in the turbines’ wake for several empirical CO2 profiles. In instances with positive or a combination of CO2 gradients, it was found that the concentration of CO2 increased in wake through downward mixing and entrainment. In a negative CO2 gradient, the opposite was found, with the wind turbine mixing away the increased surface<br> concentration and entraining down lower concentration air from above. These findings were used to make recommendations on scenarios in which wind turbines were beneficial to Direct Capture plants.<br> In addition, as part of the ongoing response to the COVID-19 pandemic, an innovative new technology was designed and constructed; a prototype photoacoustic spectrometer for the rapid detection of viruses. With the vision to become a viral "breathalyzer", the primary stage of development involved the creation of a prototype for proof-of-concept of viral detection using PAS. An extensive literature review was completed to determine optimal<br> design, with several distinct innovations integrated with the end-product in mind; such as a pure silicon resonator cell and a light-emitting diode source for low-cost, portable detection.<br> This was estimated to be of sufficient quality to detect single virions, as found through Finite Element Analysis.<br> Additionally, the validation of a proposed improvement on the medical mask, named Hy-Cu, is shown. Through various tests, Hy-Cu was found to have greater breathability than KN95 or surgical masks, as well as comparable efficiency in filtration of viral droplets.<br> Additionally, the novel inclusion of a diamond-like carbon-coated copper mesh layer resulted in viral inactivation of 99% after a period of 2 hours, allowing Hy-Cu to be safely reused without risk of transmission.<br> </p> <p> </p>