PMD Pathway for Alternative Olfactory Insect Repellent; Regulatory and Market Infrastructures Shaping Access to PMD-Based Repellents Compared to DEET in Low-Income Urban Sri Lanka
Year: 2026
Type: dissertation
Abstract: Vector-borne diseases account for nearly 17% of all infectious illnesses worldwide, causing more than 700,000 deaths annually. In Sri Lanka alone, more than 38,000 dengue cases were reported by week 38 of 2024, despite growing awareness and prevention campaigns. Protection against insect-borne disease is deeply unequal: the repellent a family uses is often determined less by choice than by what is affordable, locally stocked, and institutionally endorsed. This sociotechnical study asked how regulatory classification, procurement and retail infrastructures, and public health communication shape the affordability and availability of PMD-based repellents relative to DEET in low-income urban communities in Sri Lanka. PMD (para-menthane-3,8-diol) is a biodegradable, plant-derived alternative to the petroleum-based standard DEET, and review evidence suggests PMD can provide long-lasting repellency comparable to DEET in many contexts. Yet in many settings, plant-derived repellents remain positioned as premium or niche products, leaving them inaccessible to the populations most burdened by dengue. The chemical engineering project proposes a commercial manufacturing process for a PMD-based topical mosquito repellent spray as an alternative to products dominated by DEET. The plant is designed to produce approximately 1.71 million units per year for sale to an American market, where pricing reflects higher disposable income. The proposed process begins with biomass preparation and essential-oil recovery from lemon eucalyptus leaves, followed by citronellal enrichment, acid-catalyzed batch cyclization to PMD, and final purification. Economic analysis shows the project is attractive overall, with an after-tax ROI of 43–69%. However, a product priced for American consumers would likely exceed what low-income Sri Lankan households could afford. Together, these reports demonstrate that PMD can be manufactured at scale economically and performs comparably to DEET as an active ingredient. The remaining sociotechnical challenge is not technical feasibility but whether regulatory classification, procurement infrastructure, and public health communication will position PMD as an accessible tool for low- income Sri Lankan communities rather than a premium product priced for Western markets.
Source: Libra
DOI: 10.18130/kcwd-5r14
Author: Abedi, Parsa
Institution: University of Virginia
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7160843732