When trying to make more sustainable clothing choices, many consumers follow a simple rule: choose natural fibres over synthetic ones. Cotton instead of polyester. Wool instead of acrylic. Linen instead of nylon.
The logic seems straightforward. Natural fibres originate from plants or animals, while synthetic fibres are largely derived from fossil fuels. If a fibre comes from nature, it must surely be the more environmentally friendly option.
But our new review of research examining textile chemistry, fibre type and environmental consequences suggests the reality is far more complicated.
What matters is not simply where a fibre comes from, but what happens to it throughout its journey from the raw material to a finished garment. Many consumers imagine a cotton T-shirt as little more than processed plant material. Yet cotton is a water-intensive crop and, in many parts of the world, relies heavily on pesticides and fertilisers. Even after harvesting, the story doesn’t end. Before reaching the shop floor, textiles often undergo extensive chemical processing.
Fibres may be bleached, dyed, softened, strengthened or waterproofed. Some are treated to make them flame retardant or resistant to creasing, staining and microbial growth. These treatments help create the products consumers have come to expect, improving appearance, durability and performance. But they also influence how textiles behave throughout their life cycle. This affects how they degrade, what they release into the environment and how easily they can be recycled.
More than fibre type
Certifications for sustainable textiles often focus on the environmental consequences of sourcing the raw fibre itself. Cotton requires land and water. Polyester relies on fossil resources. Wool raises questions about livestock emissions and land use. These are important considerations, but they tell only part of the story.
In collaboration with colleagues at the sustainable textiles and apparel research group at the University of Manchester, we have published a systematic review that highlights how a garment’s environmental cost depends not only on the fibre itself – but also on the chemicals used throughout production and the ways in which those materials behave during use, reuse and disposal.
Our latest research shows that chemicals introduced during cultivation, fibre production, dyeing, finishing and performance enhancement can affect how textiles behave in the environment, including how they degrade, what they release and how easily they can be recycled.
For example, per- and polyfluoroalkyl substances (Pfas), often referred to as “forever chemicals”, are used to give textiles water- and stain-resistant properties but are highly persistent in the environment. Formaldehyde-based finishes improve crease resistance.
Other chemicals, including some phthalates (used to make some coatings and plastics more flexible), bisphenols (used in some plastic and textile coating manufacture), heavy metals and dye compounds, have also been associated with environmental or human health concerns depending on how they are used and managed throughout a product’s life cycle.
This complexity is often invisible to consumers. Two garments made from the same fibre may have very different environmental footprints depending on how they were processed and finished.
Public and policy discussions about textile pollution have largely focused on synthetic microplastics. Yet our review of the evidence suggests the picture is more complex. Natural fibres such as cotton and wool, together with regenerated cellulose fibres such as viscose and lyocell (derived from wood pulp), have also been widely detected in rivers, oceans and rain or cloud particles.
This does not mean natural fibres are necessarily more harmful than synthetic alternatives. Rather, it highlights that pollution cannot be understood simply by looking at fibre origin.
As textiles are worn, washed and eventually discarded, both fibres and the chemicals applied to them can be released into the environment. They may enter rivers and oceans through wastewater, accumulate in soils through the application of sewage sludge, or become airborne as dust and fibre fragments. Understanding how fibres and the chemicals they carry move through the environment is now an active area of research for scientists around the world and one that is reshaping how we think about the true environmental footprint of our clothes.
