Abstract
Mosquitoes have existed alongside our human ancestors for over a million years, carrying along with them some of the most menacing diseases such as Zika, dengue, malaria, and a handful of others. While many of us can protect ourselves from mosquitoes by applying our favorite brand repellent, (sub)tropical communities around the globe face a larger issue at hand: reliable repellent access. These communities are notably prone to mosquito transmission of deadly diseases due to climate and overall substandard living conditions. As a result, insect repellents have become an essential commodity amongst consumers and governments to mitigate the risks of vector-borne diseases. Although repellents are evidently seen as critical in our society, many repellent products today still suffer with flaws surrounding safe usage and more importantly, universal access.
In the PMD Pathway for Alternative Olfactory Mosquito Repellent, our groups technical paper lays out the basis of design and economics for manufacturing PMD-based topical sprays using lemon eucalyptus, or C. Citriodora, harvested in India as the primary feedstock in our process. The motivation for this project is with the growing health and environmental concerns of the active ingredient DEET, which has controlled and dominated the repellent market till this day. As DEET continues to surface new risks, interest towards alternative botanical repellents has escalated over the recent years.
The final product is defined as a consumer spray repellent with 20 wt% PMD as the primary active ingredient, 40 wt% mix of bio-derived and commercial ethanol as the primary carrier solvent, and the rest composed of trace oil terpenes and hydrosol. The scale of our chemical process is based on 21% of the current PMD market share which corresponds to 37,000 kg of PMD per year or 1.71 million 4-oz sellable units per year. At the process level, the design employs fundamental chemical processing equipment typically used in the essential oil extraction industry such as distillation and liquid-liquid separators. What makes this process unique is the incorporation of PMD synthesis under an acid catalyst. The back end of the design focuses on utilizing the spent leaves for bio-ethanol conversion as additional feedstock to our formulation, helping promote circular economy and vertical integration. The back-end process utilizes hydrolysis and fermentation as the primary unit operations for ethanol production. Although the back-end design appears appealing, our findings show that economically, given the high cost of OPEX, it would be prudent to source ethanol from an outside vendor rather than producing it in-house.
The STS paper, From Pharmacy Shelves to Fevala Streets, explores what determines real day-to-day protection in the Brazilian favela communities. Favelas sit at the very intersection of informal housing, uneven public services, poor sanitation, and dense social networks, making these communities key sites for examining health inequities tied to distributive injustice. At high level, the paper raises the question of, “how do social conditions and chemistry both unite to protect human health?” The paper uses DEET and PMD as a comparative lens and focuses on the main research question: how do policy/regulation, city infrastructure, and mass media shape availability and use of DEET versus naturally based PMD repellents in the favelas? The paper employes the actor-network theory to examine the different human and non-human actors that lead to privileging DEET over PMD. For my methods, the paper employs literature alongside policy documents, documentaries, and articles to support the research.
The technical and the STS projects both address two different failure points in the public-health protection sector. While the technical report focuses on scale-up production feasibility, the STS paper shows that production is only one node in a larger network. If certain active ingredients fail to be legitimized and communicated by the government, stocked reliably in local retail stores, and effectively communicated through the channels the favelados use, then enhancing product performance can still fail to reduce risk where the social burden is highest. My paper concludes that improving repellent chemistry and scale of production can only achieve so much. Although improvement in chemistry is necessary it is not sufficient. If we seek to enhance protection for people in communities such as the favelas, alignment between manufacturing, regulations, infrastructure, and communication are critical.
