The phrase “natural fragrance” may sound environmentally friendly. But once we consider the land and water needed to grow plants and the energy used to extract scent from flowers or roots, origin alone becomes a difficult basis for an answer.
A study published by Martz and colleagues in 2023 examined 27 fragrance ingredients used in cosmetics. It calculated impacts up to production for natural extracts, petroleum-derived ingredients and materials made using biotechnology, and compared the results with simpler assessment methods.
Comparing the production of 1 kg of an ingredient
At the centre of the study was life-cycle assessment, or LCA. It estimates environmental impacts by adding up the resources and energy used in cultivation or collection, transport, extraction and chemical conversion, along with the resulting emissions.
The basis of comparison was the production of 1 kg of a fragrance ingredient at a MANE fragrance-company factory. Upstream stages involved in obtaining raw materials were included, but incorporation into cosmetics, use and end-of-life treatment were outside this LCA.
The comparison therefore did not use amounts matched for equal scent intensity or equal use in a particular application. An ingredient with a smaller impact per kilogram will not necessarily perform better environmentally in a finished perfume.
Impacts vary widely even among natural extracts
Results for the 27 ingredients showed substantial variation within origin categories. If a plant yields only a small proportion of extract, large quantities of plant material are needed to obtain a little fragrance ingredient. Cultivation practices and extraction processes also affected the results.
For some natural ingredients, agriculture accounted for a substantial share of the burden, involving land use, fertilizers, pesticides and fuel for agricultural machinery. For solvent-extracted ingredients, solvent production, quantities used and the energy required for recovery were also important.
Even among resin-based extracts, different solvent requirements changed the estimated environmental impacts. Their shared plant origin alone could not explain these differences. The green-leaf-smelling compound cis-3-hexenol also showed large differences in environmental impact between plant extraction and chemical synthesis, because yields and processes differed even for the same molecule.
How do a simplified score and LCA differ?
The study compared an LCA-based assessment called SPOT with GREEN MOTION™, a method developed by MANE. The latter scores matters such as resource use, process efficiency and the hazards of substances handled according to green chemistry principles.
The two approaches showed broadly similar tendencies, but did not necessarily give the same rankings. GREEN MOTION™ includes processes that use hazardous substances, whereas LCA adds up inputs and emissions. What is counted, and how far the assessment extends, differ.
A simplified assessment, for example, may not fully capture upstream agricultural burdens. Conversely, the issue of handling hazardous substances in a process is not fully represented by the LCA results in this study. The methods complement one another rather than either providing every answer. SPOT’s overall score is also a weighted combination of 14 environmental impacts, not a direct measurement of a single quantity.
Is producing less waste enough?
The researchers also compared the E-factor, which expresses the amount of waste relative to the amount of product. It helps identify inefficiency in a process, but cannot by itself determine its overall environmental impact.
Reducing waste may require more energy or increase the production burden of another solvent or raw material. The authors therefore proposed using simplified indicators during early process design, then applying LCA once the design is more developed to verify improvements.
Paying attention to modelling assumptions
The calculations used databases and estimates as well as data collected from factories and producers. Where water or energy requirements could not be measured directly for individual ingredients, they were allocated using factors such as processing time and temperature.
The model also included assumptions such as assigning no burden to the collection stage for wild plants gathered by hand. This does not establish that such collection has no real ecological effects. Results can change with agricultural conditions and data quality.
The research involved scientists from L’Oréal, MANE and the environmental-assessment company EVEA. It offers concrete comparisons using company production data, not a universal ranking of ingredients and producers worldwide.
Summary
The study suggests that which material is produced, by which process and with what efficiency matters more than a natural or synthetic label alone. Natural fragrances have opportunities to reduce impacts, and synthetic fragrances have process-specific challenges too.
The authors identified improvements in cultivation, extraction and conversion, and the use of by-products, as major opportunities. Using simplified assessments to identify problems and LCA to examine upstream stages can help avoid improvements that merely shift the burden elsewhere. They also proposed grouping fragrance ingredients with similar environmental profiles as a step toward assessing complex fragrances without disclosing commercially confidential formulations.
References
Martz, P., Phan, T. V. T., L’Haridon, J., Beausoleil, M.-H., Lafaye, K., Gérand, Y., & Gallardo, C. (2023). Environmental profile of the production of fragrance ingredients used in cosmetic products: comparative analysis of results obtained by life cycle assessment and the green chemistry-based eco-design tool GREEN MOTION™. Green Chemistry, 25, 6365–6382. DOI: 10.1039/d2gc04860d / Publisher’s original article. The original paper was checked in the full-text reprint supplied by the Royal Society of Chemistry on ResearchGate. The original article is published under CC BY-NC 4.0.
